Planned maintenance
A system upgrade is planned for 10/12-2024, at 12:00-13:00. During this time DiVA will be unavailable.
Change search
Refine search result
12 1 - 50 of 83
CiteExportLink to result list
Permanent link
Cite
Citation style
  • harvard-cite-them-right
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Agnihotri, Swarnima
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Integrated products biorefinery options within the Swedish pulp and paper industry: Current status2024In: Sustainable Chemistry for the Environment, ISSN 2949-8392, Vol. 7, article id 100128Article in journal (Refereed)
    Abstract [en]

    Pulp and paper manufacturing ranks as one of the most water and energy-intensive sectors globally, invariablyleading to significant environmental pollution e.g. issues related to air pollution and waste disposal. Also, asglobal competition intensifies, prices of forest products are expected to keep decreasing. To ensure their viability,traditional producers must augment their revenue streams by diversifying into the production of bioenergy andbiomaterials, alongside traditional wood, pulp, and paper products. A feasible solution is the integrated productsbiorefineries which provide a distinctive chance to pulp and paper industry to enhance revenues as well asreduce their environmental impact. Since pulp and paper stands as the predominant industry in Sweden, thisreview article explores the emerging biorefinery process options and main technological pathways beingdeveloped within Swedish pulp and paper mills. It also delves into the significant challenges that are beingencountered in this evolving landscape and what possibilities lie ahead for responsible and sustainable pulp andpaper operations. 

    Download full text (pdf)
    fulltext
  • 2.
    Akintunde, Moyinoluwa
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business. Department of Microbiology, University of Ibadan, Ibadan, Nigeria.
    Adebayo-Tayo, B C
    Department of Microbiology, University of Ibadan, Ibadan, Nigeria.
    Ishola, M M
    Department of Energy and Environment, Göteborg Energi, Gothenburg, Sweden.
    Zamani, Akram
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Bacterial Cellulose Production from agricultural Residues by two Komagataeibacter sp. Strains2022In: Bioengineered, ISSN 2165-5979, E-ISSN 2165-5987, Vol. 13, no 4, p. 10010-10025Article in journal (Refereed)
    Abstract [en]

    Agricultural residues are constantly increasing with increased farming processes, and improper disposal is detrimental to the environment. Majority of these waste residues are rich in lignocellulose, which makes them suitable substrate for bacterial fermentation in the production of valueadded products. In this study, bacterial cellulose (BC), a purer and better form of cellulose, was produced by two Komagataeibacter sp. isolated from rotten banana and kombucha drink using corncob (CC) and sugarcane bagasse (SCB) enzymatic hydrolyzate, under different fermentation conditions, that is, static, continuous, and intermittent agitation. The physicochemical and mechanical properties of the BC films were then investigated by Fourier Transformed Infrared Spectroscopy (FTIR), Thermogravimetry analysis, Field Emission Scanning Electron Microscopy (FESEM), and Dynamic mechanical analysis. Agitation gave a higher BC yield, with Komagataeibacter sp. CCUG73629 producing BC from CC with a dry weight of 1.6 g/L and 1.4 g/L under continuous and intermittent agitation, respectively, compared with that of 0.9 g/L in HS medium. While BC yield of dry weight up to 1.2 g/L was obtained from SCB by Komagataeibacter sp. CCUG73630 under continuous agitation compared to that of 0.3 g/L in HS medium. FTIR analysis showed BC bands associated with cellulose I, with high thermal stability. The FE-SEM analysis showed that BC fibers were highly ordered and densely packed. Although the BC produced by both strains showed similar physicochemical and morphological properties, the BC produced by the Komagataeibacter sp. CCUG73630 in CC under intermittent agitation had the best modulus of elasticity, 10.8 GPa and tensile strength, 70.9 MPa. [GRAPHICS]

    Download full text (pdf)
    fulltext
  • 3. Alinezhad, S.
    et al.
    Mirabdollah, A.
    Forgács, Gergely
    University of Borås, School of Engineering.
    Feuk-Lagerstedt, Elisabeth
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Expression of keratinase gene in Bacillus megaterium using an expression vector of pHIS1525.SPlipA and utilization of the resulting recombinant strain for chicken feather degradation prior to biogas production2009Conference paper (Other academic)
    Abstract [en]

    An increasing quantity of chickens is being utilized annually in the poultry industry, producing a huge volume of chicken feather waste which presents a high quality supply of keratin. Keratinases possessing high level of keratinolytic activity on insoluble keratin play a crucial role in hydrolyzing chicken feathers. Ever since the discovery of proteolytic ability as well as water solubility of keratinase, many industrial processes regarding keratinase application have been developed. A recently invented application to handle poultry waste is to utilize feathers for biogas production. Obviously, large amount of keratinase is required to break down the keratin prior to further conversion to biogas. Previously, several researches have shown that certain bacteria are able to produce keratinase but it is still a challenge to find out which bacteria is the most reliable source for the production with high efficiency. These challenges gave rise to the molecular biologists to bring the focus on gene cloning to develop recombinant strains resulting in overproduction of keratinase. Over the course of various cloning and expression experiments of similar proteins, it was found that Bacillus megaterium could be a susceptible host cell for keratinase production. In our study, the keratinase gene from the chromosomal DNA of Bacillus licheniformis ATCC®53757 was PCR amplified and subsequently cloned into Bacillus megaterium expression vector, pHIS1525.SPlipA. Bacillus megaterium ATCC®14945 strain was transformed with the recombinant plasmid, pKERHIS1525.SPlipA. The KER gene was expressed under xylose inducible promoter, and the product was then purified using Ni-NTA affinity chromatography. After 18 h of incubation an extracellular keratinase activity of 29U ml-1 was achieved (one unit of activity was determined as the amount of enzyme required to an increase of 0.01 in A420 after 30 min of incubation at 37°C). The recombinant strain was further examined for feather degradation using intact chicken feather waste as carbon source. The chopped chicken feathers were partially degraded by the recombinant strain after three days of incubation and the total macroscopic digestion was ultimately observed after seven days resulting in a yellowish peptide rich fermentation broth. The biogas potential of the hydrolysate will be compared with that of untreated feathers by performing anaerobic batch digestion experiments.

  • 4. Andreas, Billy
    et al.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Cahyari, Khamdan
    Setiadi, Tjandra
    Effects of Acid: Pretreatment of Inoculums and Substrate Concentration for Batch Thermophilic Biohydrogen Production from Starch - Rich Synthetic Wastewater2011In: lntemational Symposium on Southeast Asian Water Environment Part 1, 2011Conference paper (Refereed)
    Abstract [en]

    The objective of this study is to investigate the biohydrogen production in a thermophilic temperature at various acid - pretreatment of inoculums and substrate concentration of starch - ri ch synthetic wastewater, i.e. tapioca and potato synthetic one . Batch tests were conducted in 118 mL batch reactor s under thermophilic temperature (55 0 C) by natu ral mixed culture from a biogas plant. Biohydrogen production in ten days fermentation at a range of acid - pretreatment inoculum s from 5 to 6 and substrate synthetic tapioca and pot ato wastewater concentration from 5 to 50 g/L were evaluated. The maximum yield of 19.06 mmol H 2 /gVS added for synthetic potato wastewater and of 18.15 mmol H 2 /g VS added for synthetic tapioca wastewater were obtained at acid - pretreatment of inoculums of 5 and the substrate concentration of 10 g/L. The content of biohydrogen in th e biogas has a range between 41% and 43%, moreover there was no significant methane observed. For the pH inoculums of 5, acetic and n - butyric acids were found as main volatile fatty acid s in the biohydrogen fermentation . The results suggested that the starch - rich synthetic wastewater is one of potential sources of renewable energy from organic wastewater to produce biohydrogen.

    Download full text (pdf)
    FULLTEXT01
  • 5.
    Aslanzadeh, Solmaz
    et al.
    University of Borås, School of Engineering.
    Berg, Andreas
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Biogas Production from N-Methylmorpholine-N-oxide (NMMO) Pretreated Forest Residues2014In: Applied Biochemistry and Biotechnology, ISSN 0273-2289, E-ISSN 1559-0291, Vol. 172, no 6, p. 2998-3008Article in journal (Refereed)
    Abstract [en]

    Lignocellulosic biomass represents a great potential for biogas production. However, a suitable pretreatment is needed to improve their digestibility. This study investigates the effects of an organic solvent, N-Methylmorpholine-N-oxide (NMMO) at temperatures of 120 and 90 °C, NMMO concentrations of 75 and 85 % and treatment times of 3 and 15 h on the methane yield. The long-term effects of the treatment were determined by a semicontinuous experiment. The best results were obtained using 75 % NMMO at 120 °C for 15 h, resulting in 141 % increase in the methane production. These conditions led to a decrease by 9 % and an increase by 8 % in the lignin and in the carbohydrate content, respectively. During the continuous digestion experiments, a specific biogas production rate of 92 NmL/gVS/day was achieved while the corresponding rate from the untreated sample was 53 NmL/gVS/day. The operation conditions were set at 4.4 gVS/L/day organic loading rate (OLR) and hydraulic retention time (HRT) of 20 days in both cases. NMMO pretreatment has substantially improved the digestibility of forest residues. The present study shows the possibilities of this pretreatment method; however, an economic and technical assessment of its industrial use needs to be performed in the future.

  • 6.
    Aslanzadeh, Solmaz
    et al.
    University of Borås, School of Engineering.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Pretreatment of straw fraction of manure for improved biogas production2011In: BioResources, E-ISSN 1930-2126, Vol. 6, no 4, p. 5193-5205Article in journal (Refereed)
    Abstract [en]

    Pretreatment of straw separated from cattle and horse manure using N-methylmorpholine oxide (NMMO) was investigated. The pretreatment conditions were for 5 h and 15 h at 120 °C, and the effects were evaluated by batch digestion assays. Untreated cattle and horse manure, both mixed with straw, resulted in 0.250 and 0.279 Nm3 CH4/kgVS (volatile solids), respectively. Pretreatment with NMMO improved both the methane yield and the degradation rate of these substrates, and the effects were further amplified with more pretreatment time. Pretreatment for 15 h resulted in an increase of methane yield by 53% and 51% for cattle and horse manure, respectively. The specific rate constant, k0, was increased from 0.041 to 0.072 (d-1) for the cattle and from 0.071 to 0.086 (d-1) for the horse manure. Analysis of the pretreated straw shows that the structural lignin content decreased by approximately 10% for both samples and the carbohydrate content increased by 13% for the straw separated from the cattle and by 9% for that separated from the horse manure. The crystallinity of straw samples analyzed by FTIR show a decrease with increased time of NMMO pretreatment.

    Download full text (pdf)
    fulltext
  • 7.
    Aslanzadeh, Solmaz
    et al.
    University of Borås, School of Engineering.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Pretreatment of straw fraction of manure for improved biogas production2011In: BioResources, E-ISSN 1930-2126, Vol. 6, no 4, p. 5193-5205Article in journal (Refereed)
  • 8. Berglund Odhner, Peter
    et al.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Kabir, Maryam M.
    University of Borås, School of Engineering.
    Shabbauer, Anna
    Biogas from lignocellulosic biomass2012Report (Other academic)
    Abstract [en]

    Grontmij AB has cooperated with the University of Borås to evaluate the technological and economical possibilities for biogas production from substrates containing lignocellulose, such as forest residues, straw and paper. The state of knowledge regarding biogas production from cellulosic biomass has been summarized. The research in the field has been described, especially focusing on pretreatment methods and their results on increased gas yields. An investigation concerning commercially available pretreatment methods and the cost of these technologies has been performed. An economic evaluation of biogas production from lignocellulosic materials has provided answers to questions regarding the profitability of these processes. Pretreatment with steam explosion was economically evaluated for three feedstocks – wood, straw and paper – and a combination of steam explosion and addition of NaOH for paper. The presented costs pertain to costs for the pretreatment step as it, in this study, was assumed that the pretreatment would be added to an existing plant and the lignocellulosic substrates would be part of a co-digestion process. The results of the investigation indicate that it is difficult to provide a positive net result when comparing the cost of pretreatment versus the gas yield (value) for two of the feedstocks – forest residues and straw. This is mainly due to the high cost of the raw material. For forest residues the steam pretreatment cost exceeded the gas yield by over 50 %, mainly due to the high cost of the raw material. For straw, the production cost was similar to the value of the gas. Paper showed the best economic result. The gas yield (value) for paper exceeded the pretreatment cost by 15 %, which makes it interesting to study paper further.

  • 9. Borges, Marisa
    et al.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Towards zero waste: a comparative study on solid waste management between Curitiba in Brazil and Borås in Sweden2014Conference paper (Refereed)
  • 10.
    Bátori, Veronika
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Åkesson, Dan
    University of Borås, Faculty of Textiles, Engineering and Business.
    Zamani, Akram
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Anaerobic degradation of bioplastics: A review2018In: Waste Management, Vol. 80, p. 406-413Article in journal (Refereed)
    Abstract [en]

    Anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW), leading to renewableenergy production in the form of methane, is a preferable method for dealing with the increasing amountof waste. Food waste is separated at the source in many countries for anaerobic digestion. However, thepresence of plastic bags is a major challenge for such processes. This study investigated the anaerobicdegradability of different bioplastics, aiming at potential use as collecting bags for the OFMSW. Thechemical composition of the bioplastics and the microbial community structure in the AD processaffected the biodegradation of the bioplastics. Some biopolymers can be degraded at hydraulic retentiontimes usually applied at the biogas plants, such as poly(hydroxyalkanoate)s, starch, cellulose and pectin,so no possible contamination would occur. In the future, updated standardization of collecting bags forthe OFMSW will be required to meet the requirements of effective operation of a biogas plant.

  • 11. Carillo-Nieves, Danay
    et al.
    Zumalacárregui-de Cárdenas, Lourdes
    Franco-Rico, Rafael
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Kinetic of biogas production from oil palm empty fruit bunches2014In: Dyna, ISSN 0012-7353, E-ISSN 2346-2183, Vol. 81, no 187, p. 96-101Article in journal (Refereed)
  • 12. Carrillo Nieves, Danay
    et al.
    Karimi, Keikhosro
    University of Borås, School of Engineering.
    Sárvári Horvátha, Ilona
    University of Borås, School of Engineering.
    Improvement of biogas production from oil palm empty fruit bunches (OPEFB)2011In: Industrial crops and products (Print), ISSN 0926-6690, E-ISSN 1872-633X, Vol. 34, no 1, p. 1097-1101Article in journal (Refereed)
    Abstract [en]

    Oil palm empty fruit bunches (OPEFB), a waste lignocellulosic material, which is the main byproduct of vegetable oil production industries in Indonesia and Malaysia, was utilized as a source for biogas production. Pretreatments using NaOH as well as phosphoric acid were investigated to improve the biogas production. Clear positive effects of the pretreatments on the yield of methane were observed. The best improvement was achieved when 8% NaOH for 60 min was used for the pretreatment, which resulted in 100% improvement in the yield of methane production. In addition, treatment with phosphoric acid resulted in 40% improvement in the methane yield compared with that of the untreated material. The results showed that the carbohydrate content of OPEFB could be efficiently converted to methane under the anaerobic digestion process. 97% of the theoretical value of methane production was achieved after the pretreatment with NaOH for 60 min. Moreover, the initial rate of methane production was also increased by more than 85% after the treatment with NaOH compared with that of the untreated OPEFB.

    Download full text (pdf)
    FULLTEXT01
  • 13.
    Foereid, B.
    et al.
    NIBIO, Norwegian Institute of Bioeconomy Research Pb 115, NO-1431 Ås, Norway.
    Szocs, J.
    NIBIO, Norwegian Institute of Bioeconomy Research Pb 115, NO-1431 Ås, Norway.
    Patinvoh, R. J.
    Department of Chemical and Polymer Engineering, Faculty of Engineering, Lagos State University, Lagos 100268, Nigeria.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Effect of anaerobic digestion of manure before application to soil – benefor nitrogen utilisation?2021In: International Journal of Recycling of Organic Waste in Agriculture, ISSN 2195-3228, E-ISSN 2251-7715, Vol. 10, no 1, p. 89-99Article in journal (Refereed)
    Abstract [en]

    Purpose Anaerobic digestion produces renewable energy, biogas, from organic residues, but also digestate, a valuable organic fertiliser. Previous studies have indicated that digestate contains ample plant available nitrogen (N), but there are also concerns about greenhouse gas (GHG) emissions after application of digestates to soil. The aim of this study was to compare digestate and undigested feedstock for fertiliser effect as well as greenhouse gas emissions during the next season. Method Digestate and its feedstock, manure, were compared as N fertilisers for wheat. Mixing digestate with biochar before application was also tested. After harvest, soil samples were frozen and dried. Then GHG emissions immediately after a re-wetting of dry soil and after thawing of frozen soil were measured to determine emissions after a non-growing season (dry or cold). Results All N in digestate was plant available, while there was no significant N fertiliser effect of the undigested manure. N2 O emissions were higher after a dry season than after freezing, but the undigested manure showed higher emissions during thawing than those detected during thawing of soils from any of the other treatments. Conclusion Anaerobic digestion makes N available to plants, and when residues with much N that is not plant available the first season are used, the risk of N2 O emission next spring is high. © 2021, Islamic Azad University. All rights reserved.

    Download full text (pdf)
    fulltext
  • 14.
    Forgacs, G.
    et al.
    University of Borås, School of Engineering.
    Lundin, M.
    University of Borås, School of Engineering.
    Taherzadeh, M.J.
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Pretreatment of chicken feather waste for improved biogas production2013In: Applied Biochemistry and Biotechnology, ISSN 0273-2289, E-ISSN 1559-0291, Vol. 169, no 7, p. 2016-2028Article in journal (Refereed)
    Abstract [en]

    This study deals with the utilization of chicken feather waste as a substrate for anaerobic digestion and improving biogas production by degradation of the compact structure of the feather keratin. In order to increase the digestibility of the feather, different pretreatments were investigated, including thermal pretreatment at 120 °C for 10 min, enzymatic hydrolysis with an alkaline endopeptidase [0.53–2.66 mL/g volatile solids (VS) feathers] for 0, 2, or 24 h at 55 °C, as well as a combination of these pretreatments. The effects of the treatments were then evaluated by anaerobic batch digestion assays at 55 °C. The enzymatic pretreatment increased the methane yield to 0.40 Nm3/kg VSadded, which is 122 % improvement compared to the yield of the untreated feathers. The other treatment conditions were less effective, increasing the methane yield by 11–50 %. The long-term effects of anaerobic digestion of feathers were examined by co-digestion of the feather with organic fraction of municipal solid waste performed with and without the addition of enzyme. When enzyme was added together with the feed, CH4 yield of 0.485 Nm3/kg VS−1 d−1 was achieved together with a stable reactor performance, while in the control reactor, a decrease in methane production, together with accumulation of undegraded feather, was observed.

  • 15.
    Forgács, Gergely
    et al.
    University of Borås, School of Engineering.
    Alinezhad, Saeid
    Mirabdollah, Amir
    Feuk-Legerstedt, Elisabeth
    University of Borås, School of Engineering.
    Sávári Horváth, Ilona
    University of Borås, School of Engineering.
    Biological treatment of chicken feather waste for improved biogas production2011In: Journal of Environmental Sciences(China), ISSN 1001-0742, E-ISSN 1878-7320, Vol. 23, no 10, p. 1747-1753Article in journal (Refereed)
    Abstract [en]

    A two-stage system was developed which combines the biological degradation of keratin-rich waste with the production of biogas. Chicken feather waste was treated biologically with a recombinant Bacillus megaterium strain showing keratinase activity prior to biogas production. Chopped, autoclaved chicken feathers (4%, W/V) were completely degraded, resulting in a yellowish fermentation broth with a level of 0.51 mg/mL soluble proteins after 8 days of cultivation of the recombinant strain. During the subsequent anaerobic batch digestion experiments, methane production of 0.35 Nm3/kg dry feathers (i.e., 0.4 Nm3/kg volatile solids of feathers), corresponding to 80% of the theoretical value on proteins, was achieved from the feather hydrolyzates, independently of the pre-hydrolysis time period of 1, 2 or 8 days. Cultivation with a native keratinase producing strain, Bacillus licheniformis resulted in only 0.25 mg/mL soluble proteins in the feather hydrolyzate, which then was digested achieving a maximum accumulated methane production of 0.31 Nm3/kg dry feathers. Feather hydrolyzates treated with the wild type B. megaterium produced 0.21 Nm3 CH4/kg dry feathers as maximum yield.

  • 16.
    Forgács, Gergely
    et al.
    University of Borås, School of Engineering.
    Niklasson, Claes
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    J. Taherzadeh, Mohammad
    University of Borås, School of Engineering.
    Methane production from feather waste pretreated with Ca(OH)2: Process development and economical analysis2014In: Waste and Biomass Valorization, ISSN 1877-2641, E-ISSN 1877-265X, Vol. 5, no 1, p. 65-73Article in journal (Refereed)
    Abstract [en]

    This study investigated the industrial application of feather waste as a substrate for anaerobic digestion. Feather was pretreated with 0–0.2 Ca(OH)2 g/g TSfeather (total solids of feathers) for 30–120 min at 100–120 °C, in order to increase the digestibility, and to enhance the methane yield in a subsequent digestion at 55 °C. Based on the results of the batch digestion, an industrial process was developed, which can achieve 0.40 Nm3/kg VSfeather (volatile solids of feathers) methane yield from the pretreated feathers, while it fulfills the animal by-product hygenization requirements as well. This base case of the industrial pretreatment process was designed using SuperPro Designer® for utilizing 2,500 tons of feathers per year, which is the waste stream from an average slaughterhouse with a capacity of 60,000 broilers per day. The production cost of the methane is estimated to be 0.475 EUR/Nm3, while the investments on the pretreatment unit requires 0.97 million EUR as total capital investment, and 0.25 million EUR/year for operating cost. However, the process is sensitive to the plant capacity. Changing the plant capacity from 625 to 10,000 tons of feather per year, results in reducing the biogas production cost from 1.177 to 0.203 EUR/Nm3. In addition, sensitivity analysis was performed on the base case to investigate the effect of the value of the incoming feather on the overall process profitability. The results showed that the proposed investment could be considered as being financially viable in the case of production of upgraded biomethane even without the current gate fee system.

  • 17.
    Forgács, Gergely
    et al.
    University of Borås, School of Engineering.
    Pourbafrani, Mohammad
    Niklasson, Claes
    Taherzadeh, Mohammad
    University of Borås, School of Engineering.
    Horváth Sárvari, Ilona
    University of Borås, School of Engineering.
    Methane production from citrus wastes: process development and cost estimation2011In: Journal of chemical technology and biotechnology (1986), ISSN 0268-2575, E-ISSN 1097-4660, Vol. 87, no 2, p. 250-255Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Because of its extreme toxicity for microorganisms, the limonene content of citrus wastes (CWs) has been a major obstacle to the conversion of CWs to biofuels. The main objective of this study was to develop a new process for the utilization of CWs that can be economically feasible when the supply of CW is low. RESULTS: Steam explosion pre-treatment was applied to improve the anaerobic digestibility of CWs, resulting in a decrease of initial limonene concentration by 94.3%. A methane potential of 0.537 ± 0.001 m3 kg−1 VS (volatile solids) was obtained during the following batch digestion of treated CWs, corresponding to an increase of 426% compared with that of the untreated samples. Long-term effects of the treatment were further investigated by a semi-continuous co-digestion process. A methane production of 0.555 ± 0.0159 m3 CH4 kg−1 VS day−1 was achieved when treated CWs (corresponding to 30% of the VS load) were co-digested with municipal solid waste. CONCLUSION: The process developed can easily be applied to an existing biogas plant. The equipment cost for this process is estimated to be one million USD when utilizing 10 000 tons CWs year−1. 8.4 L limonene and 107.4 m3 methane can be produced per ton of fresh citrus wastes in this manner.

  • 18.
    Habagil, Moshe
    et al.
    Vatten & Miljö i Väst AB, P.O. Box 110, SE-311 22 Falkenberg, Sweden.
    Keucken, Alexander
    Vatten & Miljö i Väst AB, P.O. Box 110, SE-311 22 Falkenberg, Sweden.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Biogas Production from Food Residues-The Role of Trace Metals and Co-Digestion with Primary Sludge2020In: Environments, E-ISSN 2076-3298, Vol. 7, no 6Article in journal (Refereed)
    Abstract [en]

    The majority of municipal Wastewater Treatment Plants (WWTPs) in Sweden produce biogas from sewage sludge. In order to increase the methane production, co-digestion of internal sludge with Organic Fraction of Municipal Solid Waste (OFMSW) might be feasible in the future. The objective of this study was therefore to find a beneficial solution for the utilization of OFMSW at the WWTP in Varberg, Sweden. The effects of co-digesting primary sludge (PS) and OFMSW collected in the municipality, in different mixing ratios, were investigated by semi-continuous anaerobic digestion assays. Furthermore, the effects of the addition of a commercial trace elements mixture solution (CTES), available on the market in Sweden, were also examined. Co-digestion of OFMSW and PS resulted in specific methane yields of 404, 392, and 375 NmL CH4/g volatile solids (VS), obtained during semi-continuous operations of 301, 357 and 385 days, for the reactors fed with OMFSW:PS ratio of 4:1, 3:1, and 1:1, and at maximum organic loading rates (OLRs) achieved of 4.0, 4.0 and 5.0 gVS/L/d, respectively. Furthermore, mono-digestion of OFMSW failed already at OLR of 1.0 gVS/L/d, however, an OLR of 4.0 gVS/L/d could be achieved with addition of 14 mu L/g VS Commercial Trace Element Solutions (CTES) leading to 363 mL CH4/g VS methane production. These experiments were running during 411 days. Hence, higher process efficiency was obtained when using co-digestion of OFMSW and PS compared to that of OFMSW in mono-digestion. Co-digestion is a more feasible option where a balanced Carbon/Nitrogen (C/N) ratio and nutrient supply can be maintained.

  • 19. Hashemi, Seyed Sajad
    et al.
    Karimi, Keikhosro
    Nosratpour, Mohammad Javad
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Efficient Biogas and Ethanol Production from Safflower Straw Using Sodium Carbonate Pretreatment2016In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 30, no 12, p. 10592-10601Article in journal (Refereed)
  • 20. Holliger, Christof
    et al.
    Alves, Madalena
    Andrade, Diana
    Angelidaki, Irini
    Astals, Sergi
    Baier, Urs
    Bougrier, Claire
    Buffière, Pierre
    Carballa, Marta
    de Wilde, Vinnie
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Towards a standardization of biomethane potential tests2016In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 74, no 11, p. 2515-2522Article in journal (Refereed)
    Abstract [en]

    Production of biogas from different organic materials is a most interesting source of renewable energy. The biomethane potential (BMP) of these materials has to be determined to get insight in design parameters for anaerobic digesters. A workshop was held in June 2015 in Leysin Switzerland to agree on common solutions to the conundrum of inconsistent BMP test results. A discussion covers actions and criteria that are considered compulsory ito accept and validate a BMP test result; and recommendations concerning the inoculum substrate test setup and data analysis and reporting ito obtain test results that can be validated and reproduced.

  • 21.
    Jansson, Anette
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Patinvoh, R. J.
    Effect of organic compounds on dry anaerobic digestion of food and paper industry wastes.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Effect of organic compounds on dry anaerobic digestion of food and paper industry wastes2020In: Bioengineered, ISSN 2165-5979, E-ISSN 2165-5987, Vol. 11, no 1, p. 502-509Article in journal (Refereed)
    Abstract [en]

    Effects of antimicrobial compounds on dry anaerobic digestion (dry-AD) processes were investigated. Four compounds with known inhibition effects on traditional wet digestion, i.e. car-3-ene, hexanal, 1-octanol and phenol were selected and investigated at concentrations of 0.005%, 0.05% and 0.5%. Food waste (FW) and Paper waste (PW) were used as model substrates, all assays were running with the substrate to inoculum ratio of 1:1 (VS basis) corresponding to 15% TS in reactors. Generally, increasing concentrations of inhibitors resulted in decreasing methane yields with a few exceptions; in all these specific cases, long, lag phase periods (60 days) were observed. These adaptation periods made possible for the microbial systems to acclimatize to otherwise not preferred conditions leading to higher methane yields. Comparing the effects of the four different groups, phenols had the highest inhibitory effects, with no methane production at the highest amount added, while the lowest effects were obtained in cases of car-3-ene. Furthermore, the results showed that adding inhibitors up to a certain concentrations can repair the balance in AD process, slowing down the degradation steps, hence making it possible for the methanogens to produce a higher amount of methane. This phenomenon was not observed in case of PW, which is already a slow degradable substrate in its nature. © 2020, © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.

    Download full text (pdf)
    fulltext
  • 22.
    Kabir, Maryam M.
    et al.
    University of Borås, School of Engineering.
    Aslanzadeh, Solmaz
    University of Borås, School of Engineering.
    Teghammar, Anna
    University of Borås, School of Engineering.
    del Pilar Castillo, Maria
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Biogas production from lignocelluloses by N-methylmorpholine-N-oxide (NMMO) pretreatment: Achievements and Challenges2014Conference paper (Other academic)
  • 23.
    Kabir, Maryam M
    et al.
    University of Borås, School of Engineering.
    del Pilar Castillo, Maria
    Taherzadeh, Mohammad. J.
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Effect of the N-methylmorpholine-N-oxide (NMMO) pretreatment on anaerobic digestion of forest residues2013In: BioResources, E-ISSN 1930-2126, Vol. 8, no 4, p. 5409-5423Article in journal (Refereed)
    Abstract [en]

    Pretreatment of forest residues using N - methylmorpholine - N - oxide (NMMO or NMO) prior to anaer obic digestion was investigated , where the effects of particle size, NMMO concentration , and pretreatment time were the primary focus. The pretreatments were carried out on forest residues; with different particle size s of 2, 4 and 8 mm , at 120 °C for 3, 7 , and 15 h in two different modes of NMMO - treatment : dissolution by 85% NMMO and swelling without dissolution using 75% NMMO solution in water . The pretreatment process led to minor changes in the composition of the forest residues . The best improvement in methane yield of the forest residues was achieved by pretreatment using 85% NMMO for 15 h at 120 °C. This treatment resulted in 0.1 7 Nm 3 /kg VS methane yield , which corresponds to 83 % of the expected theoretical yield of carbohydrates present in the material. Additionally, the accumulated methane yield and the rate of the methane production were highly affected by the amounts of remaining NMMO when it was not well separated during the washing and filtration step s after the treatment. The p resence o f concentrations even as low as 0.008 % NMMO resulted in a decrease in the final methan e yield by 45% , while the presence of 1% of this solvent in the digester completely terminated the anaerobic digestion process.

  • 24. Kabir, Maryam M.
    et al.
    Forgács, Gergely
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Biogas from Lignocellulosic Materials2015In: Lignocellulose-Based Bioproducts, Switzerland: Springer, 2015, p. 207-251Chapter in book (Other academic)
  • 25.
    Kabir, Maryam M.
    et al.
    University of Borås, School of Engineering.
    Forgács, Gergely
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Pretreatment of wool based textile wastes for enhanced biogas production2012Conference paper (Other academic)
    Abstract [en]

    Two different wool based textile wastes (TW1 and TW2) have been subjected for biogas production. TW1 was composed of 70% wool and 30% polyamide (PA), while TW2 consisted of 70% wool, 18% PA and 12% kermel (protective polyamide-imide fibre). Two pre-treatments: thermal treatment, enzymatic treatment and combinations of these two were performed to enhance the methane yield. Determining the soluble protein concentrations in the treated samples showed that the additional thermal treatment and the enzyme concentration had significant positive effect on the degradation of wool. Samples treated with thermal and combination treatments were therefore selected for anaerobic batch digestion assays. The best results were obtained after combination treatments resulting in methane yields of 0.33-0.43 Nm3/kg VS, and 0.21-0.26 Nm3/kg VS, for TW1 and TW2, respectively, while only 0.21 and 0.05 Nm3/kg VS methane production was measured after the thermal treatment. The methane yields of untreated samples were close to zero.

    Download full text (pdf)
    FULLTEXT01
  • 26.
    Kabir, Maryam M.
    et al.
    University of Borås, School of Engineering.
    Forgács, Gergely
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    6 Biogas from Wastes2015In: Resource Recovery to Approach Zero Municipal Waste / [ed] Mohammad J. Taherzadeh, Tobias Richards, CRC Press, 2015Chapter in book (Refereed)
  • 27.
    Kabir, Maryam M.
    et al.
    University of Borås, School of Engineering.
    Forgácsa, Gergely
    University of Borås, School of Engineering. Chalmers University of Technology.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Enhanced methane production from wool textile residues by thermal and enzymatic pretreatment2013In: Process Biochemistry, ISSN 1359-5113, E-ISSN 1873-3298, Vol. 48, no 4, p. 575-580Article in journal (Refereed)
    Abstract [en]

    Methane production from two types of wool textile wastes (TW1 and TW2) was investigated. To improve the digestibility of these textiles, different pretreatments were applied, and comprised thermal treatment (at 120 ◦C for 10 min), enzymatic hydrolysis (using an alkaline endopeptidase at different levels of enzymatic loading, at 55 ◦C for 0, 2, and 8 h), and a combination of these two treatments. Soluble protein concentration and sCOD (soluble chemical oxygen demand) were measured to evaluate the effectivity of the different pretreatment conditions to degrade wool keratin. The sCOD as well as the soluble protein content had increased in both textile samples in comparison to untreated samples, as a response to the different pretreatments indicating breakdown of the wool keratin structure. The combined treatments and the thermal treatments were further evaluated by anaerobic batch digestion assays at 55 ◦C. Combined thermal and enzymatic treatment of TW1 and TW2 resulted in methane productions of 0.43 N m3/kg VS and 0.27 N m3/kg VS, i.e., 20 and 10 times higher yields, respectively, than that gained from untreated samples. The application of thermal treatment by itself was less effective and resulted in increasing the methane production by 10-fold for TW1 and showing no significant improvement for TW2.

  • 28.
    Kabir, Maryam M.
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Rajendran, K.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, M.J.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sárvári Horváth, I.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Experimental and economical evaluation of bioconversion of forest residues to biogas using organosolv pretreatment2015In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 178, p. 201-8Article in journal (Refereed)
    Abstract [en]

    The methane potential of forest residues was compared after applying organic solvent, i.e., acetic acid, ethanol, and methanol pretreatments using batch anaerobic digestion (AD). The pretreatments were performed at 190 °C with 50% (V/V) organic solvent for 60 min. The accumulated methane yields after 40 days of AD from pretreated forest residues were between 0.23 and 0.34 m3 CH4/kg VS, which shows a significant improvement compared to 0.05 m3 CH4/kg VS, from untreated forest residues. These improvements count up to 50% increase in the methane yields from the pretreated substrates based on expected theoretical yield from carbohydrates. Among the organic solvents, pretreatments with acetic acid and ethanol led to highest methane yields, i.e., over 0.30 m3 CH4/kg VS. However, techno-economical evaluation showed, pretreatment with methanol was more viable financially. The capital investments of the plant operating 20,000 tons of forest residues varied between 56 and 60 million USD, which could be recovered in less than 8 years of operation.

  • 29.
    Kabir, Maryam M.
    et al.
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Enhanced biogas production from forest residues by NMMO pretreatment2013Conference paper (Refereed)
  • 30.
    Kabir, Maryam M.
    et al.
    University of Borås, School of Engineering.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Biogas production from lignocelluloses by N-methylmorpholine-N-oxide (NMMO) pretreatment: Effect of recycling and reuse of NMMO2013In: / [ed] Shu Li, Jegatheesan Veeriah, Keir Greg, 2013Conference paper (Refereed)
  • 31.
    Kabir, Maryam M
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Dry anaerobic digestion of lignocellulosic and protein residues2015In: Biofuel Research Journal, Vol. 2, no 4, p. 309-316Article in journal (Refereed)
    Abstract [en]

    Utilisation of wheat straw and wool textile waste in dry anaerobic digestion (AD) process was investigated. Dry-AD of the individual substrates as well as co-digestion of those were evaluated using different total solid (TS) contents ranging between 6 to 30%. Additionally, the effects of the addition of nutrients and cellulose- or protein-degrading enzymes on the performance of the AD process were also investigated. Dry-AD of the wheat straw resulted in methane yields of 0.081 – 0.200 Nm3CH4/kgVS with the lowest and highest values obtained at 30 and 21% TS, respectively. The addition of the cellulolytic enzymes could significantly increase the yield in the reactor containing 13% TS (0.231 Nm3CH4/kg VS). Likewise, degradation of wool textile waste was enhanced significantly at TS of 13% with the addition of the protein-degrading enzyme (0.131 Nm3CH4/kg VS). Furthermore, the co-digestion of these two substrates showed higher methane yields compared with the methane potentials calculated for the individual fractions at all the investigated TS contents due to synergetic effects and better nutritional balance.

    Download full text (pdf)
    fulltext
  • 32. Karimi, Keikhosro
    et al.
    Tabatabaei, Meisam
    Microbial Biotechnology Department, Agricultural Biotechnology Research Institute of Iran (ABRII.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Kumar, Rajeev
    6 Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California.
    Recent trends in acetone, butanol, and ethanol (ABE) production2015In: Biofuel Research Journal, E-ISSN 2292-8782, Vol. 2, no 4, p. 301-308Article in journal (Refereed)
  • 33.
    Karimi, Keikhosro
    et al.
    Department of Chemical Engineering, Isfahan University of Technology.
    Tabatabaei, Meisam
    Microbial Biotechnology Department, Agricultural Biotechnology Research Institute of Iran (ABRII.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Kumar, Rajeev
    6 Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California.
    Recent trends in acetone, butanol, and ethanol (ABE) production2015In: Biofuel Research Journal, Vol. 2, no 4, p. 301-308Article in journal (Refereed)
    Abstract [en]

    Among the renewable fuels considered as a suitable substitute to petroleum-based gasoline, butanol has attracted a great deal of attention due to its unique properties. Acetone, butanol, and ethanol (ABE) can be produced biologically from different substrates, including sugars, starch, lignocelluloses, and algae. This process was among the very first biofuel production processes which was commercialized during the First World War. The present review paper discusses the different aspects of the ABE process and the recent progresses made. Moreover, the microorganisms and the biochemistry of the ABE fermentation as well as the feedstocks used are reviewed. Finally, the challenges faced such as low products concentration and products` inhibitory effects on the fermentation are explained and different possible solutions are presented and reviewed.

  • 34.
    Kumar, Rajeev
    et al.
    6 Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California.
    Tabatabaei, Meisam
    Microbial Biotechnology Department, Agricultural Biotechnology Research Institute of Iran (ABRII.
    Karimi, Keikhosro
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Recent updates on lignocellulosic biomass derived ethanol-A review2016In: Biofuel Research Journal, E-ISSN 2292-8782, Vol. 3, no 1, p. 347-356Article in journal (Refereed)
    Abstract [en]

    Lignocellulosic (or cellulosic) biomass derived ethanol is the most promising near/long term fuel candidate. In addition, cellulosic biomass derived ethanol may serve a precursor to other fuels and chemicals that are currently derived from unsustainable sources and/or are proposed to be derived from cellulosic biomass. However, the processing cost for second generation ethanol is still high to make the process commercially profitable and replicable. In this review, recent trends in cellulosic biomass ethanol derived via biochemical route are reviewed with main focus on current research efforts that are being undertaken to realize high product yields/titers and bring the overall cost down.

  • 35.
    Lukitawesa,
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Patinvoh, Regina
    University of Borås, Faculty of Textiles, Engineering and Business.
    Millati, Ria
    Department of Food and Agricultural Product Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia..
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Factors influencing volatile fatty acids production from food wastes via anaerobic digestion2020In: Bioengineered, ISSN 2165-5979, E-ISSN 2165-5987, Vol. 11, no 1, p. 39-52Article in journal (Refereed)
    Abstract [en]

    Volatile fatty acids (VFAs) are intermediate products in anaerobic digestion. The effect of substrate loading or inoculum to substrate ratio (ISR), the addition of methanogen inhibitor, O2 presence, control the reactor's pH, and inoculum adaptation on the VFAs production from food waste through acidogenesis process was investigated in this study. Addition of 2-bromoethane sulfonic (BES) as methanogen inhibitor suppressed VFA consumption by methanogens at ISR 1:1. At higher substrate loading (ISR 1:3), methane production can be suppressed even without the addition of BES. However, at high substrate loading, controlling the pH during acidogenesis is important to achieve high VFAs yield. Acclimatization of inoculum is also one of the strategies to achieve high VFA yield. The highest VFAs yield obtained in this work was 0.8 g VFA/g VS added at ISR 1:3, controlled pH at 6, with the presence of initial O2 (headspace unflushed).

  • 36. Mirabdollah, A.
    et al.
    Alinezhad, S.
    Feuk-Lagerstedt, Elisabeth
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Optimization of a protoplast transformation method for Bacillus Subtilis, Bacillus megaterium, and Bacillus Cereus by a plasmid pHIS1525.SplipA2009Conference paper (Other academic)
    Abstract [en]

    During the past years of gene cloning studies, Escherichia coli has always been a foremost host cell for exogenous genes expressions owing to its high level of protein production and excretion. However, problems relating to low level of extracellular production of some proteins specially the accumulation of cloned proteases within the cells have moved the attentions from E.coli to bacilli bacteria such as B. megaterium, B.subtilis, and B.cereus due to their secretion ability of many different enzymes. Bacillus megaterium is widely used for high-level expression of heterologous proteins with little or no degradation. Bacillus subtilis is a naturally competent host cell for uptake of exogenous DNA, resulting in attractive industrial applications. Bacillus cereus has sporulation capability which makes it suitable for several industrial uses. A conventional approach for transferring DNA into protoplasts or intact cells of bacillus bacteria is chemical transformation, using chemicals through chilling and then shock-heating of the suspension of cells to induce reversible permeabilization of the cell membrane to make it possible for the external DNA to enter into the cells. In most cloning experiments, the transformation with plasmid DNA is performed using Polyethylene glycol (PEG)-induced competence cells. In this study, a PEG-induced protoplast transformation protocol was developed for three different bacillus strains of Bacillus megaterium ATCC®14945, Bacillus Subtilis ATCC®6051, and Bacillus Cereus ATCC®14579. In all cases a plasmid pHIS1525.SPlipA, well working vector in B.megaterium, was applied. Protoplasts were formed in RHAF medium after treating the cells with lysozyme. Two factors, the incubation time and the lysozyme concentration have been found to play the most important role in effective protoplast formation. These two factors were further optimized in this study to elaborate a chemical transformation procedure which can possibly work for other bacillus strains as well. The optical density (A420) and the number of colony-forming units (CFUs) were determined to find the optimal conditions for each strain. The results indicate that PEG-induced protoplast transformation is a sufficient technique when using a plasmid pHIS1525.SPlipA in Bacillus genus.

  • 37. Mirmohamadsadeghi, Safoora
    et al.
    Karimi, Keikhosro
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Improvement of Solid-State Biogas Production from Wood by Concentrated Phosphoric Acid Pretreatment2016In: BioResources, E-ISSN 1930-2126, Vol. 11, no 2, p. 3230-3243Article in journal (Refereed)
    Abstract [en]

    Cellulose Solvent-And organic Solvent-Based lignocellulose fractionation (COSLIF) has been repeatedly shown to be a Cost-Effective and promising process to modify the structure of different lignocelluloses. It has been repeatedly reported to improve enzymatic hydrolysis and ethanol production from different lignocelluloses. In this study, COSLIF was used to improve biomethane production from pine (softwood), poplar (soft hardwood), and berry (hard hardwood) via solid state anaerobic digestion (SSAD). Feed to inoculum (F/I) ratio, which plays a major role in SSAD, was set to 3, 4, and 5. After the pretreatment, 39, 33, and 24% higher methane yield from pine was achieved for F/I ratios of 3, 4, and 5, respectively. However, the methane yield from the hardwoods was not improved by the pretreatment, which was related to overloading of the digester. Compositional analysis showed considerable reduction in hemicellulose and lignin content by the pretreatment. Structural changes in the woods, before and after the pretreatment, were examined by X-Ray diffractometer and scanning electron microscopy. The results showed that the crystallinity of cellulose was decreased and accessible surface area was drastically increased by the pretreatment.

  • 38. Mirmohamadsadeghi, Safoora
    et al.
    Karimi, Keikhosro
    Zamani, Akram
    Amiri, Hamid
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Enhanced solid-state biogas production from lignocellulosic biomass by organosolv pretreatment2014In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, Vol. 2014Article in journal (Refereed)
  • 39. Mohseni Kabir, M.
    et al.
    Niklasson, C.
    Taherzadeh, M.J.
    University of Borås, School of Engineering.
    Sárvári Horváth, I.
    University of Borås, School of Engineering.
    Biogas production from lignocelluloses by N-methylmorpholine-N-oxide (NMMO) pretreatment: Effects of recovery and reuse of NMMO2014In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 161, p. 446-450Article in journal (Refereed)
    Abstract [en]

    The effects of N-methylmorpholine-N-oxide (NMMO) pretreatment on barley straw and forest residues were investigated for biogas production. The pretreatments were performed at 90 °C with 85% NMMO for 3–30 h. The best pretreatment conditions resulted in 100% improvement in methane yield during the subsequent digestion compared to that of the untreated lignocelluloses. Methane yields of 0.23 and 0.15 Nm3 CH4/kg VS were obtained from barley straw and forest residues, respectively, corresponding to 88% and 83% of the theoretical yields. In addition, the effects of the pretreatment with recovered and reused NMMO was also studied over the course of five cycles. Pretreatment with recycled NMMO showed the same performance as the fresh NMMO on barley straw. However, pretreatment of forest residues with recycled NMMO resulted in 55% reduction in methane yield.

  • 40.
    Momayez, Forough
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business. Isfahan University of Technology.
    Karimi, Keikhosro
    Isfahan University of Technology.
    Karimi, Shiva
    Isfahan University of Technology.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Efficient hydrolysis and ethanol production from rice straw by pretreatment with organic acids and effluent of biogas plant2017In: RSC Advances, E-ISSN 2046-2069, Vol. 7, no 80, p. 50537-50545Article in journal (Refereed)
    Abstract [en]

    The effluent of biogas production plant was used for the pretreatment of rice straw for the improvement of ethanol production. In addition, the organic active ingredients of the effluent, i.e., acetic, butyric, lactic and propionic acids (1-4%), as well as water were employed for the pretreatment at 100 and 140 °C. The results indicated that pretreatment at 100 °C had no significant effect on the performance of subsequent enzymatic hydrolysis and ethanol production by simultaneous saccharification and fermentation (SSF). Among different types of organic acids presented in the effluent, lactic acid showed a better performance. The highest concentration of glucose and ethanol were achieved after 72 h enzymatic hydrolysis and SSF from the straw pretreated at 140 °C with 4% lactic acid. Applying the effluent for the straw pretreatment at 140 °C resulted in an increase in glucose and ethanol concentrations by 42.4 and 47.5%, respectively, compared to those from untreated samples. SEM, FTIR, BET, BJH, and compositional analyses were used to characterize the changes in the structure and composition of rice straw by the pretreatment. Changes in the straw swelling, cellulose crystallinity, pore size distribution, and composition were responsible for the acquired improvements.

    Download full text (pdf)
    fulltext
  • 41. Murto, Marika
    et al.
    Gereby, Erik
    Holström, David
    del Pilar Castillo, Maria
    Lagerkvist, Anders
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Increased methane production by unused substrates and process development2014Conference paper (Other academic)
  • 42.
    Nair, Ramkumar B
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Kabir, Maryam M.
    Lennartsson, Patrik R.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Integrated Process for Ethanol, Biogas, and Edible Filamentous Fungi-Based Animal Feed Production from Dilute Phosphoric Acid-Pretreated Wheat Straw2017In: Applied Biochemistry and Biotechnology, ISSN 0273-2289, E-ISSN 1559-0291, p. 1-15Article in journal (Refereed)
    Abstract [en]

    Integration of wheat straw for a biorefinery-based energy generation process by producing ethanol and biogas together with the production of high-protein fungal biomass (suitable for feed application) was the main focus of the present study. An edible ascomycete fungal strain Neurospora intermedia was used for the ethanol fermentation and subsequent biomass production from dilute phosphoric acid (0.7 to 1.2% w/v) pretreated wheat straw. At optimum pretreatment conditions, an ethanol yield of 84 to 90% of the theoretical maximum, based on glucan content of substrate straw, was observed from fungal fermentation post the enzymatic hydrolysis process. The biogas production from the pretreated straw slurry showed an improved methane yield potential up to 162% increase, as compared to that of the untreated straw. Additional biogas production, using the syrup, a waste stream obtained post the ethanol fermentation, resulted in a combined total energy output of 15.8 MJ/kg wheat straw. Moreover, using thin stillage (a waste stream from the first-generation wheat-based ethanol process) as a co-substrate to the biogas process resulted in an additional increase by about 14 to 27% in the total energy output as compared to using only wheat straw-based substrates. .[on SciFinder (R)]

  • 43. Pages-Diaz, Jhosane
    et al.
    Westman, Johan
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Pereda-Reyes, Ileana
    Sarvari Horvath, Ilona.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Semi-continuous co-digestion of solid cattle slaughterhouse wastes with other waste streams: Interactions within the mixtures and methanogenic community structure.2015In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 273, p. 28-36Article in journal (Refereed)
    Abstract [en]

    The effect of mixt. interactions, i.e., synergy and antagonism, previously obsd. in batch operation mode were evaluated under semi-continuous co-digestion of slaughterhouse waste (SB) and its different combinations with manure (M), various crops (VC), and municipal solid waste (MSW). The effects on the process performance and the microbial community structure were studied. The digestion of SB failed at an OLR of 0.9 g VS/L-day. However, stable performance with higher loadings was obsd. for mixts. that displayed synergy obtained earlier in the batch mode (i.e., SB + M, SB + VC + MSW). Bacterial and Archaeal groups increased for the SB + M and SB + VC + MSW, compared with the digestion of SB alone and that for SB + VC. The combination that showed antagonistic effects (SB + VC) resulted in unstable operation and poor representation of methanogens. It was proved that synergetic or antagonistic effects obsd. in batch mode due to the different mixt. compns. could be correlated to process performance, as well as the development of the microbial community structure during semi-continuous operation. [on SciFinder(R)]

  • 44.
    Pagés Díaz, Jhosané
    et al.
    University of Borås, School of Engineering.
    Pereda Reyes, Ileana
    Lundin, Magnus
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Co-digestion of different waste mixtures from agro-industrial activities: Kinetic evaluation and synergetic effects2011In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 102, no 23, p. 10834-10840Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Several wastes from agro-industrial activities were mixed in different ratios to evaluate the co-digestion process. Methane yield (YCH4), specific methanogenic activity (SMA) and a kinetic parameter (k0) were determined. A second feeding was also performed to examine the recovery of bacterial activity after exhaustion. Mixture ratios of 1:1:1:1 and 1:3:4:0.5 (w/w) showed the best performance, with YCH4 of 664; 582 NmL CH4/gVSsubstrate, as well as SMA of 0.12; 0.13 gCODNmLCH4/gVSinoculum/d, respectively, during the digestion of the first feed. It was possible to relate synergetic effects with enhancement in YCH4 by up to 43%, compared with values calculated from YCH4 of the individual substrates. All batches started up the biogas production after an exhaustion period, when a second feed was added. However, long lag phases (up to 21 days) were observed due to stressed conditions caused by the substrate limitation prior to the second feed.

  • 45.
    Pagés Díaz, Jhosané
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business. Technical University of Havana “José A. Echeverría”.
    Pereda Reyes, Ileana
    Technical University of Havana “José A. Echeverría”.
    Sanz, Jose Luise
    Autonomous University of Madrid.
    Lundin, Magnus
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    A comparison of process performance during the anaerobic mono-and co-digestion of slaughter house waste through different operational modes2017In: Journal of Environmental Sciences(China), ISSN 1001-0742, E-ISSN 1878-7320Article in journal (Refereed)
    Abstract [en]

    The use of consecutive feeding was applied to investigate the response of the microbial biomass to a second addition of substrates in terms of biodegradation using batch tests as a promising alternative to predict the behavior of the process. Anaerobic digestion (AD) of the slaughterhouse waste (SB) and its co-digestion with manure (M), various crops (VC), and municipal solid waste were evaluated. The results were then correlated to previous findings obtained by the authors for similar mixtures in batch and semi-continuous operation modes. AD of the SB failed showing total inhibition after a second feeding. Co-digestion of the SB + M showed a significant improvement for all of the response variables investigated after the second feeding, while co-digestion of the SB + VC resulted in a decline in all of these response variables. Similar patterns were previously detected, during both the batch and the semi-continuous modes.

  • 46.
    Pagés Díaz, Jhosané
    et al.
    University of Borås, School of Engineering.
    Pereda Reyes, Ileana
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Pérez Olmo, Jesús
    An approach to the codigestion process of solid slaughterhouse waste, manure, various crop and municipal solid waste2011Conference paper (Other academic)
    Abstract [en]

    A codigestion process was evaluated when mixing different ratios of agro-industrial residues, i.e. slaughterhouse waste (SB); manure (M); various crop residues (VC); and municipal solid waste (MSW). Methane yield (YCH4) and specific methanogenic activity (SMA) were determined by anaerobic batch digestion of the different substrates and substrate mixtures. The performance of the codigestion was also evaluated by kinetics (k0) based on the methane production rate. The investigated residues and their mixtures were found to have high potentials for the production of biogas. The codigestion process showed to be a feasible option with positive influence in both energy production and environmental care. Taking into account significance differences, the best results were obtained with a mixture ratio of 1:3:4:0.5 based on the w/w content of SB, M, VC, and MSW, respectively, which showed a proper combination of high values in YCH4, SMA and k0 during the anaerobic process. The effect of temperature suggested that thermophilic conditions are suitable to treat these residues. Response variables were severely affected by mesophilic conditions, diminishing in at least 45% of the thermophilic value when a mixture ratio of 2:3:3:0 based on the w/w content of SB:M:VC:MSW was selected. It is suggested to study the influence of individual component within the mixture for every response variable. Consecutive feedings are also suggested in order to step forward to continuous process and evaluate possible inhibitions.

  • 47.
    Pagés Díaz, Jhosané
    et al.
    University of Borås, School of Engineering.
    Pereda Reyes, Ileana
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Lundin, Magnus
    University of Borås, School of Engineering.
    Anaerobic co-digestion of solid slaughterhouse wastes with agro-residues: Synergistic and antagonistic interactions determined in batch digestion assays2014In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 245, p. 89-98Article in journal (Refereed)
    Abstract [en]

    Different mixture ratios of solid cattle slaughterhouse wastes (SB), manure (M), various crops (VC), and municipal solid wastes (MSW) were investigated for biogas production. The objective was to explore possible significant synergistic effects obtained from the combination of these different substrates. The performance of the process was assessed in thermophilic anaerobic batch co-digestion assays, using a four factor mixture design and methane yield (Y-CH4) and specific methane production rate (r(scH4)) as response variables. The highest methane yield, 655 NmL CH4/g VS was obtained when equal parts (ww) of SB, M, VC, and MSW were combined, while the combination of SB, M, and MSW resulted in the highest specific methane production rate (43 NmL CH4/g VS/d). A mixture design model was fitted to data in order to appraise synergistic and antagonistic interactions. Mixing all four substrates resulted in a 31% increase of the expected yield which was calculated from the methane potential of the individual fractions, clearly demonstrating a synergistic effect due to more balanced nutrient composition enhancing the anaerobic digestion process. However, no significant antagonistic effects were observed. In order to maximize both response variables simultaneously, a response surface method was employed to establish the optimal combination of substrate mixtures. The statistical results and analysis of the biological process gave a coherent picture of the results. (C) 2014 Elsevier B.V. All rights reserved.

    Download full text (pdf)
    fulltext
  • 48.
    Pagés-Díaz, J.
    et al.
    University of Borås, School of Engineering.
    Pereda-Reyes, I.
    Sárvári-Horváth, Ilona
    University of Borås, School of Engineering.
    Lundin, M.
    University of Borås, School of Engineering.
    Synergistic and antagonistic interactions during anaerobic co-digestion of slaughterhouse wastes, manure, various crop and municipal solid waste residues2013Conference paper (Other academic)
  • 49.
    Pagés-Díaz, J.
    et al.
    University of Borås, School of Engineering.
    Sárvári Horváth, Ilona
    University of Borås, School of Engineering.
    Pérez-Olmo, J.
    Pereda-Reyes, I.
    Co-digestion of bovine slaughterhouse wastes, cow manure, various crops and municipal solid waste at thermophilic conditions: a comparison with specific case running at mesophilic conditions2013In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 67, no 5, p. 989-995Article in journal (Refereed)
    Abstract [en]

    A co-digestion process was evaluated when mixing different ratios of agro-industrial residues, i.e. bovine slaughterhouse waste (SB); cow manure (M); various crop residues (VC); and municipal solid waste (MSW) by anaerobic batch digestion under thermophilic conditions (55 °C). A selected study case at mesophilic condition (37 °C) was also investigated. The performance of the co-digestion was evaluated by kinetics (k(0)). The best kinetic results were obtained under thermophilic operation when a mixture of 22% w/w SB, 22% w/w M, 45% w/w VC and 11% w/w MSW was co-digested, which showed a proper combination of high values in r(s)CH(4) and k(0) (0.066 Nm(3)CH(4)/kgVS*d, 0.336 d(-1)) during the anaerobic process. The effect of temperature on methane yield (Y(CH4)), specific methane rate (r(s)CH(4)) and k(0) was also analyzed for a specific study case; there a mixture of 25% w/w of SB, 37.5% w/w of M, 37.5% of VC and 0% of MSW was used. Response variables were severely affected by mesophilic conditions, diminishing to at least 45% of the thermophilic values obtained for a similar mixture. The effect of temperature suggested that thermophilic conditions are suitable to treat these residues.

  • 50.
    Patel, Alok
    et al.
    Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental, and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden.
    Mahboubi, Amir
    University of Borås, Faculty of Textiles, Engineering and Business.
    Sárvári Horváth, Ilona
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Rova, Ulrika
    Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental, and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden.
    Christakopoulos, Paul
    Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental, and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden.
    Matsakas, Leonidas
    Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental, and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden.
    Volatile Fatty Acids (VFAs) Generated by Anaerobic Digestion Serve as Feedstock for Freshwater and Marine Oleaginous Microorganisms to Produce Biodiesel and Added-Value Compounds2021In: Frontiers in Microbiology, E-ISSN 1664-302X, Vol. 12, article id 614612Article in journal (Refereed)
    Abstract [en]

    Given an increasing focus on environmental sustainability, microbial oils have been suggested as an alternative to petroleum-based products. However, microbial oil production relies on the use of costly sugar-based feedstocks. Substrate limitation, elevated costs, and risk of contamination have sparked the search for alternatives to sugar-based platforms. Volatile fatty acids are generated during anaerobic digestion of organic waste and are considered a promising substrate for microbial oil production. In the present study, two freshwater and one marine microalga along with two thraustochytrids were evaluated for their potential to produce lipids when cultivated on volatile fatty acids generated from food waste via anaerobic digestion using a membrane bioreactor. Freshwater microalgae Auxenochlorella protothecoides and Chlorella sorokiniana synthesized lipids rich in palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), and linoleic acid (C18:2). This composition corresponds to that of soybean and jatropha oils, which are used as biodiesel feedstock. Production of added-value polyunsaturated fatty acids (PUFA) mainly omega-3 fatty acids was examined in three different marine strains: Aurantiochytrium sp. T66, Schizochytrium limacinum SR21, and Crypthecodinium cohnii. Only Aurantiochytrium sp. T66 seemed promising, generating 43.19% docosahexaenoic acid (DHA) and 13.56% docosapentaenoic acid (DPA) in total lipids. In summary, we show that A. protothecoides, C. sorokiniana, and Aurantiochytrium sp. T66 can be used for microbial oil production from food waste material.

    Download full text (pdf)
    fulltext
12 1 - 50 of 83
CiteExportLink to result list
Permanent link
Cite
Citation style
  • harvard-cite-them-right
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf