Rice straw was successfully converted to ethanol by separate enzymatic hydrolysis and fermentation by Mucor indicus, Rhizopus oryzae, and Saccharomyces cerevisiae. The hydrolysis temperature and pH of commercial cellulase and beta-glucosidase enzymes were first investigated and their best performance obtained at 45 degrees C and pH 5.0. The pretreatment of the straw with dilute-acid hydrolysis resulted in 0.72 g g (1) sugar yield during 48 h enzymatic hydrolysis, which was higher than steam-pretreated (0.60 g g (1)) and untreated straw (0.46 g g(-1)). Furthermore, increasing the concentration of the dilute-acid pretreated straw from 20 to 50 and 100 g L-1 resulted in 13% and 16% lower sugar yield, respectively. Anaerobic cultivation of the hydrolyzates with M. indicus resulted in 0.36-0.43 g g(-1) ethanol, 0.11-0.17 g g(-1) biomass, and 0.04-0.06 g g(-1) glycerol, which is comparable with the corresponding yields by S. cerevisiae (0.37-0.45 g g(-1) ethanol, 0.04-0.10 g g(-1) biomass and 0.05-0.07 glycerol). These two fungi produced no other major metabolite from the straw and completed the cultivation in less than 25 h. However, R. oryzae produced lactic acid as the major by-product with yield of 0.05-0.09 g g(-1). This fungus had ethanol, biomass and glycerol yields of 0.33-0.41, 0.06-0.12, and 0.03-0.04 g g(-1), respectively. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.

Sustainable provision of chemicals and materials is undoubtedly a defining factor in guaranteeing economic, environmental, and social stability of future societies. Among the most sought-after chemical building blocks are volatile fatty acids (VFAs). VFAs such as acetic, propionic, and butyric acids have numerous industrial applications supporting from food and pharmaceuticals industries to wastewater treatment. The fact that VFAs can be produced synthetically from petrochemical derivatives and also through biological routes, for example, anaerobic digestion of organic mixed waste highlights their provision flexibility and sustainability. In this regard, this review presents a detailed overview of the applications associated with petrochemically and biologically generated VFAs, individually or in mixture, in industrial and laboratory scale, conventional and novel applications.

In this work two different examples of water absorbtion in polymers are studied by Monte Carlo simulations. Both of them are of large technical and commercial impotance. The first example is the water absorption in polyethylene cables where the water absorption plays a crucial role in the degradation of the cable insulation and thus should be as low as possible. The second example is bio-based superabsorbents made from denatured protein where water absorption capability is the prime desired property. Methods Gibbs Ensemble Monte Carlo simulations [1] were used to study the hydration of polymers. All simulations are performed with two boxes, one of which is filled with water at the start of the simulation, whereas the other contains polymer molecules and possible ions. The polymer molecules are not allowed to swap boxes whereas the water molecules are allowed to do so thus constituting an osmotic Gibbs ensemble [2]. For the polyethylene a connectivity-altering algorithm was used whereas the protein molecules were simulated using a side-chain regrowth model in addition to traditional Monte Carlo moves. For the polyethylene, the TraPPE [3] force field was used and the protein molecules, the Amber force field [4] was used. Water was modelled using simple point charge models [5]. Electrostatic interactions are treated using Ewald summation methods. The protein molecules were of different amino acid compositions and in different conformations, e.g., β-turns and random coils obtained using the amorphous cell method[6]. Studies were made with different degrees of charging on, e.g., lysine side chains mimicking different ionization states. Results The studies of polyethylene revealed the importance of ions left from the polymerisation catalyst for the absorbtion of water and the concomitant degradation of polyethylene cable insulation. Also the absorption properties of the protein molecules is strongly related to the presence of charged groups and fully charged protein molecules absorb large amounts of water. However, neither native nor denatured protein molecules show superabsorbing properties (i.e. absorbing hundreds of times their own mass) as they show in experimental studies and the reasons for this discrepancy will be discussed. References 1. A.Z. Panagiotopoulos, Mol. Phys. 61, 813 (1987). 2. E. Johansson, K. Bolton, D.N. Theodorou, P. Ahlström, J. Chem. Phys., 126, 224902 (2007). 3. M.G. Martin, and J.I. Siepmann, J. Phys. Chem. B, 103, 4508-4517 (1999). 4. W.D. Cornell, P. Cieplak, C.I. Bayly, I.R. Gould, K.M. Merz Jr, D.M. Ferguson, D.C. Spellmeyer, T. Fox, J.W. Caldwell, P.A. Kollman (1995). J. Am. Chem. Soc. 117, 5179–5197. 5. H. J. C. Berendsen, J. P. M. Postma and W. F. van Gunsteren, in Intermolecular Forces, B. Pullman, ed. (Reidel, Dordrecht, 1981) p. 331; H. J. C. Berendsen, J. R. Grigera and T. P. Straatsma, J. Phys. Chem. 91, 6269 (1987). 6. D.N. Theodorou, U.W. Suter, Macromolecules, 18, 1467 (1985).

Filamentous fungi serve as potential candidates in the production of different value-added products. In the context of food, there are several advantages of using filamentous fungi for food. Among the main advantages is that the fungal biomass used food not only meets basic nutritional requirements but that it is also rich in protein, low in fat, and free of cholesterol. This speaks to the potential of filamentous fungi in the production of food that can substitute animal-derived protein sources such as meat. Moreover, life-cycle analyses and techno-economic analyses reveal that fungal proteins perform better than animal-derived proteins in terms of land use efficiency as well as global warming. The present article provides an overview of the potential of filamentous fungi as a source of food and food supplements. The commercialization potential as well as social, legal and safety issues of fungi-based food products are discussed.

In this study, the effects of different treatments of the oat slurry on the nutritional, functional, and sensorial properties of oat milk were evaluated. The sprouting and sprouting–acidic treatments have the highest oat milk yield (91.70%) and protein extraction yield (82.74%), respectively. The protein concentrations of alkali, sprouting–acidic, and α-amylase–alkali treatments were significantly (p < .05) higher than other treatments. The alkali treatments showed higher fat content (0.66%). In addition, acidic and alkali treatments in single or combined with other treatments showed the highest dry matter and energy value. The carbohydrate content of α-amylase–alkali treatment (4.35%) was higher than other treatments and also, all acidic treatments showed higher ash content (>1) compared to the other treatments. Furthermore, the sprouting–α-amylase and acidic–α-amylase showed the lowest starch (0.28%) and the highest reducing sugar content (3.15%) compared to the other treatments, respectively. Moreover, the α-amylase–alkali treatment showed the highest total phenolic content and antioxidant activity (342.67 mg GAE/L and 183.08 mg BHT eq/L, respectively). Furthermore, sensory evaluation of most treatments showed acceptable scores (≥7) for consumers, especially in the case of α-amylase, sprouting, and α-amylase–sprouting treatments. Results show that the different treatments had different effects on the nutritional, functional, and sensorial properties of oat milk. In conclusion, from the nutritional and functional point of view, the two-stage treatments were more effective than singular treatments on investigated factors proposing their application in functional plant milk preparation. 

The fungus Rhizopus delemar was grown on bread waste in a submerged cultivation process and wet-laid into films. Alkali or enzyme treatments were used to isolate the fungal cell wall. A heat treatment was also applied to deactivate biological activity of the fungus. Homogenization of fungal biomass was done by an iterative ultrafine grinding process. Finally, the biomass was cast into films by a wet-laid process. Ultrafine grinding resulted in densification of the films. Fungal films showed tensile strengths of up to 18.1 MPa, a Young's modulus of 2.3 GPa and a strain at break of 1.4%. Highest tensile strength was achieved using alkali treatment, with SEM analysis showing a dense and highly organized structure. In contrast, less organized structures were obtained using enzymatic or heat treatments. A cell viability assay and fluorescent staining confirmed the biocompatibility of the films. A promising route for food waste valorization to sustainable fungal wet-laid films was established. © 2022 The Authors

A superabsorbent polymer (SAP) from chitosan was provided via carboxymethylation of chitosan, followed by cross-linking with glutaraldehyde and freeze-drying. This work was focused on an investigation of the effects of monochloroacetic acid (MCAA), sodium hydroxide, and reaction time on preparation of carboxymethylchitosan (CMCS). The CMCS products were characterized using FTIR spectroscopy, and their degrees of substitution (DS) were measured using conductimetry and FTIR analysis. The highest DS value was obtained when the carboxymethylation reaction was carried out using 1.75 g MCAA and 1.75 g NaOH per g of chitosan in 4 h. The water solubilities of the CMCS products at various pHs were also evaluated, and the results indicated a significant impact of the reaction parameters on the solubility of CMCS. The CMCSs with the highest DS value resulted in SAPs having the highest water-binding capacity (WBC). TheWBCof the best SAP measured after 10 minexposure in distilled water, 0.9% NaCl solution, synthetic urine, and artificial blood was 104, 33, 30, and 57 g/g, respectively. The WBC of this SAP at pH 2–9 passed a maximum at pH 6.

Current understanding of food waste quantities in the Brazilian retail sector is limited. In order to develop efficient measures for food waste prevention and valorisation, reliable data on waste generation and composition are necessary. In this study, a compositional analysis of street market waste was conducted in São Paulo, Brazil. In total, 4.1 tonnes of waste were sorted into 27 waste fractions, categorised using a three-level approach. The average waste generation in the studied street markets was 23.7 kg per stall, of which 12.8 kg was classified as unavoidable food waste, 3.6 kg as packaging waste, and 7.4 kg as avoidable waste. The results show large amounts of unavoidable food waste, comprised of coconut, sugarcane bagasse, and peels. A large share of the avoidable food waste is comprised of single leaves, tomatoes, oranges, and bananas. Large variations were observed among the street markets analysed, both in terms of the food waste generation rate, and composition. The results from scaling up the data at the city level indicated a total wastage of 59,300 tonnes per year, of which 18,400 tonnes are classified as avoidable food waste.

A significant by-product of bioethanol plants is whole stillage, commonly used to produce animal feed due to its nutritious value, has a potential to be used to produce various value-added products while eliminating a costly process step is an alternative approach. In this study, production and separation of additional ethanol, fungal biomass and enzyme were successfully achieved with the cultivation in membrane bioreactors in batch process condition. Process optimization studies regarding fermentation and filtration conditions were carried out. Up to 10.4 g/l ethanol per litre of used whole stillage can be produced in simultaneous saccharification and fermentation (SSF) condition without any pH adjustment and additional pretreatment step. Also, 50% diluted whole stillage provided 87% higher ethanol production comparing to non-diluted medium. Moreover, 71 % higher biomass production was obtained with the filtrate of 50% diluted whole stillage comparing to 25% diluted one. Considering the achieved results, a two-stage cultivation using SHF (Separate Hydrolysis and Fermentation) strategy in membrane bioreactors for separation of ethanol, lignin-rich stream, protein-rich fungal biomass and enzymes was proposed. The present thesis showed that the integration of filamentous fungi with membrane bioreactors can increase the range of products that can be produced from whole stillage.

Fruit and vegetable processing wastes are global challenges but also suitable sources with a variety of nutrients for different fermentative products using bacteria, yeast or fungi. The interaction of microorganisms with bioactive compounds in fruit waste can have inhibitory or enhancing effect on microbial growth. In this study, the antimicrobial effect of 10 bioactive compounds, including octanol, ellagic acid, (−)-epicatechin, quercetin, betanin, ascorbic acid, limonene, hexanal, car-3-ene, and myrcene in the range of 0–240 mg/L on filamentous fungi Aspergillus oryzae and Aspergillus niger were investigated. These fungi were both found to be resistant to all compounds except octanol, which can be used as a natural antifungal agent, specifically against A. oryzae and A. niger contamination. On the contrary, polyphenols (quercetin and ellagic acid), ascorbic acid, and hexanal enhanced A. niger biomass yield 28%, 7.8%, 16%, and 6%, respectively. Furthermore, 240 mg/L car-3-ene was found to increase A. oryzae biomass yield 8%, while a 9% decrease was observed at lower concentration, 24 mg/L. Similarly, up to 17% decrease of biomass yield was observed from betanin and myrcene. The resistant nature of the fungi against FPW bioactive compounds shows the potential of these fungi for further application in waste valorization. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Raw syngas contains tar contaminants including toluene and naphthalene, which inhibit its conversion to methane. Cell encasement in a hydrophilic reverse membrane bioreactor (RMBR) could protect the cells from hydrophobic contaminants. This study aimed to investigate the inhibition of toluene and naphthalene and the effect of using RMBR. In this work, toluene and naphthalene were added at concentrations of 0.5?1.0 and 0.1?0.2 g/L in batch operation. In continuous operation, concentration of 0?6.44 g/L for toluene and 0?1.28 g/L for naphthalene were studied. The results showed that no inhibition was observed in batch operation for toluene and naphthalene at concentrations up to 1 and 0.2 g/L, respectively. In continuous operation of free cell bioreactors (FCBRs), inhibition of toluene and naphthalene started at 2.05 and 0.63 g/L, respectively. When they were present simultaneously, inhibition of toluene and naphthalene occurred at concentrations of 3.14 and 0.63 g/L, respectively. In continuous RMBRs, no inhibition for toluene and less inhibition for naphthalene were observed, resulting in higher methane production from RMBR than that of FCBR. These results indicated that RMBR system gave a better protection effect against inhibitors compared with FCBR.

Consumption of citrus fruits and citrus juice production creates wastes, which could be valorized by using it for cultivating fungi. Before cultivation, the medium needs to be sterilized though autoclavation. Larger volumes used when autoclaving requires longer heating cycles and therefore runs the risk of degrading the medium to a greater extent. This research examines the effects of the volume lemon waste medium used while sterilizing. The aim is to find the largest volume still providing good growth for the filamentous fungus used, Rhizopus Delemar. Lemon waste was provided by Herrljunga Musteri AB and was pre-treated at 45°C for 2h. The liquid was strained and autoclaved in different volumetric series ranging from 200 – 10 000 mL, that was then used in 200 mL shake flask cultivations.  A scale up in two 3,5 L bubble column reactors was also performed from the 10 000 mL autoclaved medium, after not observing severe impacts on growth. Testing was done by weighing biomass and HPLC analysis of sugars. The yield of the biomass in the shake flasks ranged from 0,11 – 0,14 g/g sugars and the biomass concentration ranged between 2,4 - 3,0 g/L. Overall, the volume of autoclavation seems to not too be of great concern when cultivating R. Delemar on lemon waste medium in the analyzed ranges.

Comparison of vacuum and high pressure evaporated wood hydrolyzate for ethanol production by repeated fed-batch using flocculating Saccharomyces cerevisiae

Bacterial Cellulose (BC) is a biopolymer with numerous applications. The growth of BC-producing bacteria, Komagataeibacter intermedius, could be stimulated by Dekkera bruxellensis, however, the effect on BC yield needs further investigation. This study investigates BC production and biochemical changes in the K. intermedius-D. bruxellensis co-culture system. D. bruxellensis was introduced at various concentrations (10³ and 10⁶ CFU/mL) and inoculation times (days 0 and 3). BC yield was ~24% lower when D. bruxellensis was added at 10³ CFU/mL compared to K. intermedius alone (0.63 ± 0.11 g/L). The lowest BC yield was observed when 10³ CFU/mL yeast was added on day 0, which could be compromised by higher gluconic acid production (10.08 g/L). In contrast, BC yields increased by ~88% when 10⁶ CFU/mL D. bruxellensis was added, regardless of inoculation time. High BC yield might correlate with faster sugar consumption or increased ethanol production when 10⁶ CFU/mL D. bruxellensis was added on day 0. These results suggest that cell concentration and inoculation time have crucial impacts on species interactions in the co-culture system and product yield.

The recalcitrance of cellulosic biomass greatly hinders its enzymatic degradation. Expansins induce cell wall loosening and promote efficient cellulose utilization; however, the molecular mechanism underlying their action is not well understood. In this study, TlEXLX1, a fungal expansin from Talaromyces leycettanus JCM12802, was characterized in terms of phylogeny, synergy, structure, and mechanism of action. TlEXLX1 displayed varying degrees of synergism with commercial cellulase in the pretreatment of corn straw and filter paper. TlEXLX1 binds to cellulose via domain 2, mediated by CH–π interactions with residues Tyr291, Trp292, and Tyr327. Residues Asp237, Glu238, and Asp248 in domain 1 form hydrogen bonds with glucose units and break the inherent hydrogen bonding within the cellulose matrix. This study identified the expansin amino acid residues crucial for cellulose binding, and elucidated the structure and function of expansins in cell wall networks; this has potential applications in biomass utilization.

Tropical fruit wastes (TFW) are considered as the major source of food and nutrition in the topical countries. In the recent years, modernization of agriculture has increased the tropical fruit production. Higher fruit production led to an increasing abundance in the tropical fruit waste. In general, the tropical fruit waste has no economic value and ends up in landfill. But in recent years it was observed that the tropical fruit waste can be valorized to produce value-added products ranging from compost, phytochemicals, and food products to biofuels. The tropical fruit waste has great potential to produce useful products in tropical areas. This review literature is an endeavor to understand the major tropical fruit wastes and their composition. The review presents a detailed investigation on tropical fruit waste composition, its conversion potential, role of microbes in waste valorization, production of commercially valuable products and future perspectives in waste valorization.

Fast growth of bamboo species make them a suitable candidate for eco-restoration, while its lignocellulosic substrate could be used for production of high-value green products such as biofuels, chemicals, and biomaterials. Within these frameworks, this review comprehensively explored the thermochemical and biological conversion of bamboo biomass to value-added fuels and chemicals. Additionally, this review stretches an in-depth understanding of bamboo biomass lignin extraction technologies and bioengineered methodologies, as well as their biorefinery conversion strategies. Additionally, bamboo biomass often utilized in biorefineries are mostly constituted of cellulose, hemicellulose, and lignin, along with proteins, lipids, and a few micronutrients which are not utilized efficientely by current bioengineered techniques. The results indicates that the potential for producing high-value products from bamboo biomass has not been adequately explored. However, enormous potential is still available to make bamboo biorefinery technologies cost-effective, and environmentally sustainable, which are discussed in the current review comprehensively. Furthermore, processes such as pretreatment, enzymatic hydrolysis, and fermentation are essential to obtain final high-value bio-based products from bamboo biomass, therefore, this review critically designed to explore the current state of the art of these technologies. Overall, the current review establishes a zero-waste suastainable approachs for the reformation of bamboo biomass into chemicals, biofuels, and value-added products.

Rapid spread of COVID-19 disease worldwide resulted in a dramatic increase in face mask consumption. Single-used surgical face masks are manufactured using plastic fibres such as polypropylene (PP) or polyester, which cause severe environmental concerns when accumulated in landfills, primarily due to their non-degradability. Furthermore, plastic fibres are derived from petroleum, a depleting resource at an alarming rate, due to which preserving is highly recommended. Massive consumption and subsequent disposal of single-use surgical face masks urge seeking alternative solutions to conserve resources and manage the ever-growing waste issue. This study investigates the feasibility of recycling surgical facemasks. Single-use surgical face masks were subjected to mechanical recycling through melt extrusion. FTIR and TGA tests were conducted to establish the raw material’s chemical composition and thermolytic properties. Facemasks were initially shredded and melt-extruded to obtain filaments, which were subsequently pelletised. The pellets were hot-pressed using the compression moulding technique to make sheet-like panels. Tensile testing of the recycled sheet-like material exhibited failure stress of ~23 MPa and a failure strain of ~2.2%. While the failure stress was similar to the virgin PP material, the failure strain reduced significantly upon recycling. The material’s thermal conductivity was measured to be 0.404 W m−1 K−1 using Lee’s Disc Method. Thermal conductivity was increased significantly than the virgin PP material. The recycled material can be used in sheet form for applications such as thermal insulation and partition boards with further improved strength and thickness. Additionally, recycled pellets have the potential to be used as 3D printing feedstock, thereby enabling utilisation in bulk quantities.

Hydrogels are used for various applications, for example as transporters in drug delivery, in control lenses, and as superabsorbent material in diapers.[1] Most synthetic produced hydrogels are based on synthetic polymers. Even though they are efficient and cheap, they are not biodegradable and sometimes even toxic. To produce more environmental friendly and biodegradable superabsorbent polymers (Bio- SAPs), other building blocks can be used, such as polysaccharides[2] and various protein structures, for example fish shells[3], collagen[4], soy protein[5] and egg protein[6]. Experimental studies at the University of Boras show that it is possible to produce Bio-SAPs from by-products of ethanol production from ligno-cellulose.[2, 6, 7] 2. Method We have studied the absorption properties of protein structures in silico as a comparison to experimental studies. The NPT Gibbs Ensemble Monte Carlo (GEMC) simulation scheme with two phases is used in order to calculate the absorption capacity of the protein. Pure water was simulated in the first GEMC-phase and the peptide in the second phase. The simulations were made with SPC/E water model [8] and the AMBER99 atomistic force field for the peptides [9]. Furthermore, mesoscopic studies with coarse grained force fields have been done. To facilitate faster computations, we used cell lists for the atom-atom interactions, configurational bias algorithm to build the water molecules and the peptide side-chains, and the cavity bias algorithm [10] for molecule insertions. Model peptides have been studied with varying secondary structure, temperature and protonation (pH). We also plan to study how cross-links affect the absorption. One of the peptides we study is a 20 amino acid long peptide called SSP1.[11] This peptide is designed to form a fibrous structure a hydrogel, and its structure is well defined. We have also studied a peptide which changes secondary structure when changing the pH, and concentration.[12] This makes it possible to compare absorption properties with respect to the secondary structure. 3. Conclusion We have simulated peptides with the Gibbs Ensemble Monte Carlo scheme in order to study the water absorption rate dependent of structure, charge, pH and temperature. This information is useful when developing new biodegradable superabsorbent materials.

Banana peels account for about 61 million tons of waste each year globally. The aim of this project was to investigate the possibility of using banana peels as a substrate to cultivate edible filamentous fungi. The peels were subjected to physical and thermal pretreatments while variables such as changes in the medium pH, biomass concentration, fungal strain dependence, and protein content of the fungal biomass were analyzed. The experiments were carried out in three phases. The purpose of phase I was to identify which of the four fungal strains among Neurospora intermedia, Aspergillus oryzae, Rhizopus oryzae, and Rhizopus oligosporus could grow in a medium containing ball-milled banana peel powder (BPP) only. In phase II, the best performing strains from phase I in terms of biomass concentration, i.e., A. oryzae and R. oryzae, were cultivated using banana peel broth (BPB) obtained from thermal pretreatment of BPP. During this phase, the impact of medium supplementation with yeast extract was also assessed. The biomass yield for A. oryzae and R. oryzae 2.9 g/L and 1.6 g/L, respectively, yeast supplementation compared to 2.7 g/L and 0.7 g/L, respectively, without supplementation. In phase III, the experiments performed in phase II without yeast extract supplementation were scaled up, after which protein analysis was performed. A crude protein content of 8.82% was determined for A. oryzae, while in R. oryzae, a higher value of 21.1% was obtained. The protein content from both fungal strains was much higher than that present in the BPP, which was 4.8 g/L. The results showed the potential of using banana peel as a substrate to produce edible fungal biomass with higher protein content and thus has potential applications as animal feed or human food. Further studies are needed to optimize the process in order to raise the fungal biomass yield as well as increase the protein content of the biomass. In addition, comprehensive characterization of the fungal biomass would reveal other important components, such as the amino acid profile.

Fungi-based food is expected to contribute to more sustainable food systems. The present study has three focus areas: (i) aspects that affect food choices food in daily life, (ii) aspects that affect choices of fungi-based food in particular, and (iii) drivers that motivate, and barriers that prevent, engagement in cultivating fungi and cooking fungi-based food at home. One hundred and sixty participants, who were recruited using convenience sampling, filled out qualitative questionnaires. The results show that there are numerous aspects (e.g., environmental benefits, nutrition, sensory characteristics, production practices and ingredients) that are important when people choose food in daily life. In addition to curiosity, many of these aspects also affect the choice of fungi-based food. The study identified more drivers (e.g., self-providing, curiosity, awareness of ingredients) than barriers (time, knowledge, concerns about contamination) to cultivation and cooking of fungi-based food at home. The findings are relevant for the development of fungi-based food so that this type of food is engaged with, and so that it can contribute to more sustainable food systems.

Fungal fermentation is a promising strategy to secure affordable, nutritious and sustainable food. Encouraging engagement with fungi-based food is crucial to contribute to social, economic, and environmental sustainability. Reflections can trigger a sense of meaning in engaging in activities and with resources. The aim of this mixed methods study was to explore perceptions of whether participants think their own engagement with fungi-based food is consequential. To do so, the study explored ecoethical reflections relating to whether participants thought engaging with fungi-based food is beneficial or not beneficial for the environment. This study also explored glocal reflections of whether participants thought their own engagement with this kind of food is beneficial or not beneficial in ways that extend to people around them (i.e., local population) or people in other parts of the world (i.e., global population). N = 160 participants completed questionnaires. Most participants expressed a positive outlook, believing that embracing fungi-based food could promote increased sustainability and overall well-being for humans and the environment in numerous different ways. The perceptions that participants shared can affect and trigger conscious engagement with fungi-based food locally with awareness of its global impact which, in turn, can promote well-being for individuals and extend to the population level and thereby contribute to efforts at archiving sustainable development. Nevertheless, the findings highlight a necessity for more information to enable individuals to engage in knowledgeable reflections and, ultimately, act upon their values and what is meaningful to them. The results are important for future development and conceptualization of not only fungi-based food but also other food that is expected to contribute to sustainable development.

Nigeria is a tropical country with the over 150 million inhabitants out of which 70% is employed by agriculture. Bioethanol sticks out as the most important renewable biofuel and can be produced from lignocellulosic materials which include agricultural residues. Nigeria has the potentials of becoming a major biofuel ethanol producing country considering huge amount of agricultural wastes and residues generated each year, however, there is need for proper evaluation and planning before heavily investment in commercial production. This study focuses on the evaluation of the potentials of bioethanol production in Nigeria from various agricultural biomass and residues.

The work of the present thesis focused on conversion of the cellulosic part of waste textiles into biogas and ethanol, and its challenges. In 2009, the global annual fiber consumption exceeded 70 Mt, of which around 40% consisted of cellulosic material. This huge amount of fibers is processed into apparel, home textiles, and industrial products, ending up as waste after a certain time delay. Regretfully, current management of waste textiles mainly comprises incineration and landfilling, in spite of the potential of cellulosic material being used in the production of ethanol or methane. The volume of cellulose mentioned above would be sufficient for producing around 20 billion liters of ethanol or 11.6 billion Nm3 of methane per year. Nevertheless, waste textiles are not yet accepted as a suitable substrate for biofuel production, since their processing to biofuel presents certain challenges, e.g. high crystallinity of cotton cellulose, presence of dyes, reagents and other materials, and being textiles as a mixture of natural and synthetic fibers. High crystallinity of cotton cellulose curbs high efficient conversion by enzymatic or bacterial hydrolysis, and the presence of non-cellulosic fibers may create several processing problems. The work of the present thesis centered on these challenges. Cotton linter and blue jeans waste textiles, all practically pure cellulose, were converted to ethanol by SSSF, using S. cerevisiae, with a yield of about 0.14 g ethanol/g textile, only 25% of the theoretical yield. To improve the yield, a pretreatment process was required and thus, several methods were examined. Alkaline pretreatments significantly improved the yield of hydrolysis and subsequent ethanol production, the most effective condition being treatment with a 12% NaOH-solution at 0 °C, increasing the yield to 0.48 g ethanol/g textile (85% of the theoretical yield). Waste textile streams, however, are mixtures of different fibers, and a separation of the cellulosic fibers from synthetic fibers is thus necessary. The separation was not achieved using an alkaline pretreatment, and hence another approach was investigated, viz. pretreatment with N-methyl-morpholine-N-oxide (NMMO), an industrially available and environment friendly cellulose solvent. The dissolution process was performed under different conditions in terms of solvent concentration, temperature, and duration. Pretreatment with 85% NMMO at 120 °C under atmospheric pressure for 2.5 hours, improved the ethanol yield by 150%, compared to the yield of untreated cellulose. This pretreatment proved to be of major advantage, as it provided a method for dissolving and then recovering the cellulose. Using this method as a foundation, a novel process was developed, refined and verified, by testing polyester/cellulose-blended textiles, which predominate waste textiles. The polyesters were purified as fibers after the NMMO treatments, and up to 95% of the cellulose content was regenerated. The solvent was then recovered, recycled, and reused. Furthermore, investigating the effect of this treatment on anaerobic digestion of cellulose disclosed a remarkable enhancement of the microbial solubilization; the rate in pretreated textiles was twice the rate in untreated material. The overall yield of methane was, however, not significantly affected. The process developed in the present thesis appears promising for transformation of waste textiles into a suitable raw material, to subsequently be used for biological conversion to ethanol and biogas.

Ethanol production from cotton linter and waste of blue jeans textiles was investigated. In the best case, alkali pretreatment followed by enzymatic hydrolysis resulted in almost complete conversion of the cotton and jeans to glucose, which was then fermented by Saccharomyces cerevisiae to ethanol. If no pretreatment applied, hydrolyses of the textiles by cellulase and P-glucosidase for 24 h followed by simultaneous saccharification and fermentation (SSF) in 4 days, resulted in 0.140-0.145 g ethanol/g textiles, which was 25-26% of the corresponding theoretical yield. A pretreatment with concentrated phosphoric acid prior to the hydrolysis improved ethanol production from the textiles up to 66% of the theoretical yield. However, the best results obtained from alkali pretreatment of the materials by NaOH. The alkaline pretreatment of cotton fibers were carried out with 0-20% NaOH at 0 degrees C, 23 degrees C and 100 degrees C, followed by enzymatic hydrolysis up to 4 days. In general, higher concentration of NaOH resulted in a better yield of the hydrolysis, whereas temperature had a reverse effect and better results were obtained at lower temperature. The best conditions for the alkali pretreatment of the cotton were obtained in this study at 12% NaOH and 0 degrees C and 3 h. In this condition, the materials with 3% solid content were enzymatically hydrolyzed at 85.1% of the theoretical yield in 24 h and 99.1% in 4 days. The alkali pretreatment of the waste textiles at these conditions and subsequent SSF resulted in 0.48 g ethanol/g pretreated textiles used. (c) 2008 Elsevier Ltd. All rights reserved.

Thin stillage holds promise as a substrate for cultivating filamentous fungi. The suspended solids content of thin stillage directly influences biomass production. However, little attention has been given to its effects on fungal cultivation and composition, which is the focus of the current study. Various thin stillage dilutions were used to cultivate Zygomycete and Ascomycetes. Biomass and nutrient uptake were monitored during the cultivation. The harvested biomass was analyzed to assess nutrient composition in relation to fish dietary requirements. Thin stillage diluted to 75 % significantly enhanced fungal biomass production, with increases of 160 %, 213 %, and 235 % for A. oryzae, R. delemar, and N. intermedia, respectively. The harvested fungal biomass boasted approximately 50 % protein content, constituting 45 % essential amino acids. These findings underscore the potential of cultivating fungi in diluted thin stillage to boost biomass production and its high-quality nutritional composition positions it as a valuable candidate for fish feed formulations.

Anaerobic fermentation is believed to be a good and effective method for treating organic waste. Wastewater from this process is more challenging mainly due to its high content of for instance volatile fatty acids (VFA). Microalgae have shown great potential for the sustainable removal of nutrients from water sources. At the same time, algal biomass can be used to produce bio-fertilizer, biofuel, and bioplastics. Therefore, the purpose of this study was to investigate the possibility of growing two Swedish microalgae strains, adapted to the Nordic climate, on different synthetic cultures. The cultures contain two determined total concentrations of acetic acid, propionic acid, and butyric acid with three different ratios to each other. The strains studied in this experiment were Chlorella vulgaris (13–1) and Chlorococcum sp. (MC-1). The strains showed different abilities to tolerate VFA as a carbon source under the same biotic and abiotic conditions. Chlorococcum sp. was able to produce significantly higher biomass concentrations in the presence of VFA than in the reference culture without VFA. The culture with the total concentration of 2 g/L of VFA and the ratio that had the greatest content of acetic acid gave the highest biomass concentration. C. vulgaris was not affected by VFA and the algal cells in the cultures with VFA show the same behaviour as in the reference culture. Moreover, the final biomass concentrations in the presence of VFA were similar to the biomass concentration from the optimal culture. Since Chlorococcum sp. could grow on VFA it can reduce the environmental impact of industrial effluents from anaerobic fermentation in Sweden and other Nordic countries.

The inevitable need for waste valorisation and management has revolutionized the way in which the waste is visualised as a potential biorefinery for various product development rather than offensive trash. Biowaste has emerged as a potential feedstock to produce several value-added products. Bioenergy generation is one of the potential applications originating from the valorisation of biowaste. Bioenergy production requires analysis and optimization of various parameters such as biowaste composition and conversion potential to develop innovative and sustainable technologies for most effective utilization of biowaste with enhanced bioenergy production. In this context, feedstocks, such as food, agriculture, beverage, and municipal solid waste act as promising resources to produce renewable energy. Similarly, the concept of microbial fuel cells employing biowaste has clearly gained research focus in the past few decades. Despite of these potential benefits, the area of bioenergy generation still is in infancy and requires more interdisciplinary research to be sustainable alternatives. This review is aimed at analysing the bioconversion potential of biowaste to renewable energy. The possibility of valorising underutilized biowaste substrates is elaborately presented. In addition, the application and efficiency of microbial fuel cells in utilizing biowaste are described in detail taking into consideration of its great scope. Furthermore, the review addresses the significance bioreactor development for energy production along with major challenges and future prospects in bioenergy production. Based on this review it can be concluded that bioenergy production utilizing biowaste can clearly open new avenues in the field of waste valorisation and energy research. Systematic and strategic developments considering the techno economic feasibilities of this excellent energy generation process will make them a true sustainable alternative for conventional energy sources.

The dimorphic fungus Mucor indicus was grown in different forms classified as purely filamentous, mostly filamentous, mostly yeast-like and purely yeast-like, and the relationship between morphology and metabolite production, inhibitor tolerance and the cell wall composition was investigated. Low concentrations of spores in the inoculum with subsequent aeration promoted filamentous growth, whereas higher spore concentrations and anaerobic conditions promoted yeast-like growth. Ethanol was the main metabolite with glycerol next under all conditions tested. The yields of ethanol from glucose were between 0.39 and 0.42 g g−1 with productivities of 3.2–5.0 g l−1 h−1. The ethanol productivity of mostly filamentous cells was increased from 3.9 to 5.0 g l−1 h−1 by the presence of oxygen, whereas aeration of purely yeast-like cells showed no such effect. All growth forms were able to tolerate 4.6 g l−1 furfural and 10 g l−1 acetic acid and assimilate the sugars, although with different consumption rates. The cell wall content of the fungus measured as alkali insoluble materials (AIM) of the purely yeast-like cells was 26% of the biomass, compared to 8% of the pure filaments. However, the chitosan concentration of the filaments was 29% of the AIM, compared to 6% of the yeast-like cells.

This article provides an overview of biochar application for organic waste co-composting and its biochemical transformation mechanism. As a composting amendment, biochar work in the adsorption of nutrients, the retention of oxygen and water, and the promotion of electron transfer. These functions serve the micro-organisms (physical support of niche) and determine changes in community structure beyond the succession of composing primary microorganisms. Biochar mediates resistance genes, mobile gene elements, and biochemical metabolic activities of organic matter degrading. The participation of biochar enriched the α-diversity of microbial communities at all stages of composting, and ultimately reflects the high γ-diversity. Finally, easy and convincing biochar preparation methods and characteristic need to be explored, in turn, the mechanism of biochar on composting microbes at the microscopic level can be studied in depth.

Background

A cost-effective pretreatment and saccharification process is a necessary prerequisite for utilizing lignocellulosic biomass (LCB) in biofuel and biomaterials production. Utilizing a multifunctional enzyme with both pretreatment and saccharification functions in a single step for simultaneous biological pretreatment and saccharification process (SPS) will be a green method of low cost and high efficiency. Manganese peroxidase (MnP, EC 1.11.1.13), a well-known lignin-degrading peroxidase, is generally preferred for the biological pretreatment of biomass. However, exploring the role and performance of MnP in LCB conversion will promote the application of MnP for lignocellulose-based biorefineries.

Results

In this study, we explored the ability of an MnP from Moniliophthora roreri, MrMnP, in LCB degradation. With Mn2+ and H2O2, MrMnP decomposed 5.0 g/L carboxymethyl cellulose to 0.14 mM of reducing sugar with a conversion yield of 5.0 mg/g, including 40 μM cellobiose, 70 μM cellotriose, 20 μM cellotetraose, and 10 μM cellohexaose, and degraded 1.0 g/L mannohexaose to 0.33 μM mannose, 4.08 μM mannotriose, and 4.35 μM mannopentaose. Meanwhile, MrMnP decomposed 5.0 g/L lichenan to 0.85 mM of reducing sugar with a conversion yield of 30.6 mg/g, including 10 μM cellotriose, 20 μM cellotetraose, and 80 μM cellohexose independently of Mn2+ and H2O2. Moreover, the versatility of MrMnP in LCB deconstruction was further verified by decomposing locust bean gum and wheat bran into reducing sugars with a conversion yield of 54.4 mg/g and 29.5 mg/g, respectively, including oligosaccharides such as di- and tri-saccharides. The catalytic mechanism underlying MrMnP degraded lignocellulose was proposed as that with H2O2, MrMnP oxidizes Mn2+ to Mn3+. Subsequently, it forms a complex with malonate, facilitating the degradation of CMC and mannohexaose into reducing sugars. Without H2O2, MrMnP directly oxidizes malonate to hydroperoxyl acetic acid radical to form compound I, which then attacks the glucosidic bond of lichenan.

Conclusion

This study identified a new function of MrMnP in the hydrolysis of cellulose and hemicellulose, suggesting that MrMnP exhibits its versatility in the pretreatment and saccharification of LCB. The results will lead to an in-depth understanding of biocatalytic saccharification and contribute to forming new enzymatic systems for using lignocellulose resources to produce sustainable and economically viable products and the long-term development of biorefinery, thereby increasing the productivity of LCB as a green resource.

Linear livestock production practice gives rise to a number of environmental, economic, and social issues including unsustainable feed provision, resource inefficiency, and climate impacts. Provision of dietary supplements in ruminants through bioconversion of organic waste/residues is a promising way to introduce the concept of circular bioeconomy to animal feed production. Volatile fatty acids (VFAs) are natural metabolites mainly generated from the bioconversion of fiber in the rumen of ruminants, and are used as an animal's energy source and precursor for the production of animal products. Considering that VFAs can also be produced from anaerobic digestion (AD) of different organic wastes, this chapter discusses the potentials applications of waste-derived VFAs such as acetic, butyric, and propionic acids as animal feed supplementation. In this regard, first, the effect of VFAs on energy provision, dry matter intake, weight gain, weaning age, ketosis and acidosis, milk yield and composition, hormones, gastrointestinal development, etc., in ruminants are analyzed. Then the potentials of different organic waste sources for the production of VFAs through AD are presented. Finally, the purification and concentration methods such as distillation and membrane separation, whichcan be applied for the production of animal feed grade VFAs solutions, are thoroughly reviewed.

A biosuperabsorbent (Bio-SAP) hydrogel from ovalbumin (egg protein) was synthesized via modification with an acylating reagent and a bifunctional crosslinker, and its swelling behavior was investigated. The protein was acylated using ethylenediaminetetraacetic dianhydride (EDTAD), and then crosslinked by glutaraldehyde and dried. Bio-SAP provided through this method includes modification of lysyl residues in the unfolded protein by adding one or more hydrophilic carboxyl groups to increase the hydrophilicity of protein. The water binding capacity was measured in deionized water, 0.9% NaCl solution and synthetic urine, which under the best conditions were 296, 64 and 56 g/g after 24 h, respectively. In addition, the effects of EDTAD/protein ratio on the chemical modification of the protein, the various chemical neutralization agents, pH sensitivity and ionic strength, as well as temperature and particle size on the water absorption capacity with and without load and its kinetic were also investigated.

The fungus Mucor indicus is able to produce ethanol from xylose as well as dilute-acid lignocellulosic hydrolyzates. The fungus completely assimilated 10 g/L xylose as the sole carbon and energy source within 32 to 65 h at an aeration rate of 0.1 to 1.0 vvm. The highest ethanol yield was 0.16 g/g at 0.1 vvm. Xylitol was formed intermediately with a maximum yield of 0.22 g/g at 0.5 vvm., but disappeared towards the end of experiments. During cultivation in a mixture of xylose and glucose, the fungus did not assimilate xylose as long as glucose was present in the medium. The anaerobic cultivation of the fungus in the hydrolyzate containing 20% xylose and 80% hexoses resulted in no assimilation of xylose but complete consumption of the hexoses in less than 15 h. The ethanol yield was 0.44 g/g. However, the xylose in the hydrolyzate was consumed when the media were aerated at 0.067 to 0.333 vvm. The best ethanol yield was 0.44 g/g at 0.067 vvm. The results of this study suggest that M. indicus hydrolyzate can be first fermented anaerobically for hexose assimilation and subsequently continued under oxygen-limited conditions for xylose fermentation.

Oil Palm Empty Fruit Bunch (OPEFB) was hydrolyzed in a one-stage hydrolysis using dilute-sulfuric acid (0.2, 0.8%) at 170-230°C with a holding time of 5 and 15 min. The maximum yield of xylose was 135.94 g kg-1 OPEFB, obtained at 0.8% acid, 190°C and 5 min. The maximum yield of glucose was 62.70 g kg-1 OPEFB, obtained at 0.8% acid, 210°C and 5 min. Based on these results, two-stage hydrolysis was performed to produce hydrolyzates for the fermentation process. Hydrolyzate from the first stage was fermented by Mucor indicus while the hydrolyzate from the second stage was fermented by Saccharomyces cerevisiae. The corresponding ethanol yields were 0.45 and 0.46 g ethanol g-1 sugar consumed.

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.