Baker's yeast production industry generates large quantities of high chemical oxygen demand (COD) wastewater. The integration of baker's yeast wastewater (BYW) for an innovative two-step waste biorefinery process by producing protein-rich fungal biomass and biogas along with COD and nutrients removal was the main object of the present research. In the first step, fungal biomass production from BYW was investigated using four species of filamentous fungi. The maximum biomass yield of 5.13 g/L BYW containing 43.8% mycoprotein and 36.3% COD removal was achieved by A. oryzae. In the second step, to produce biogas and further remove organic matter, the effluent of fungal fermentation was subjected to anaerobic digestion and COD removal between 22.4 and 44.2% was obtained. Overall, 1 m3 of BYW yielded 5.13 kg of protein-rich biomass and 1.42 m3 of methane. Additionally, pigment production using N. intermedia was investigated, and 1.54 mg carotenoids/g biomass was produced. 

Lignocelluloses are widely investigated as renewable substrates to produce biofuels, e.g., ethanol, methane, hydrogen, and butanol, as well as chemicals such as citric acid, lactic acid, and xanthan gum. However, lignocelluloses have a recalcitrance structure to resist microbial and enzymatic attacks; therefore, many physical, thermal, chemical, and biological pretreatment methods have been developed to open up their structure. The efficiency of these pretreatments was studied using a variety of analytical methods that address their image, composition, crystallinity, degree of polymerization, enzyme adsorption/desorption, and accessibility. This paper presents a critical review of the first three categories of these methods as well as their constraints in various applications. The advantages, drawbacks, approaches, practical details, and some points that should be considered in the experimental methods to reach reliable and promising conclusions are also discussed.

Oil palm empty fruit bunch (OPEFB) is a potential raw material for production of lignocellulosic bioethanol. The OPEFB was pretreated with 8% sodium hydroxide solution at 100 °C for 10 to 90 min. Enzymatic digestion was carried out using cellulase and β-glucosidase at 45 °C for 24 h. It was then inoculated with Mucor indicus spores suspension and fermented under anaerobic conditions at 37 °C for 96 h. Sodium hydroxide pretreatment effectively removed 51-57% of lignin in the OPEFB and also its hemicellulose (40-84%). The highest glucan digestibility (0.75 g/g theoretical glucose) was achieved in 40 min NaOH pretreatment. Fermentation by M. indicus resulted in 68.4% of the theoretical ethanol yield, while glycerol (16.2-83.2 mg/g), succinic acid (0-0.4 mg/g), and acetic acid (0-0.9 mg/g) were its by-products. According to these results, the 11.75 million tons of dry OPEFB in Indonesia can be converted to 1.5 billion litres of ethanol per year.

Nizimuddinia zanardini macroalgae, harvested from Persian Gulf, was chem. characterized and employed for the prodn. of ethanol, seaweed ext., alginic acid, and biogas. In order to improve the products yields, the biomass was pretreated with dil. sulfuric acid and hot water. The pretreated and untreated biomasses were subjected to enzymic hydrolysis by cellulase (15 FPU/g) and β-glucosidase (30 IU/g). Hydrolysis yield of glucan was 29.8, 82.5, and 72.7 g/kg for the untreated, hot-water pretreated, and acid pretreated biomass, resp. Anaerobic fermn. of hydrolyzates by Saccharomycescerevisiae resulted in the max. ethanol yield of 34.6 g/kg of the dried biomass. A seaweed ext. contg. mannitol and a solid residue contg. alginic acid were recovered as the main byproducts of the ethanol prodn. On the other hand, the biogas yield from the biomass was increased from 170 to 200 m3 per ton of dried algae biomass by hot water pretreatment. [on SciFinder(R)]

Jatropha curcas L. is a tropical plant with considerable potential for producing biodiesel and other products of high economic and social interest. During the biodiesel production process from J. curcas different residues, such as shells and husks are generated. In this work, the physical characterization of J. curcas fruits was performed, and the chemical composition of a mixture of shells and husks was determined. The physical characterization revealed that shells and husks account, respectively, for 25.0 and 27.8% of the fruit weight. The compositional analyses of the material showed a rather high content of glucans (32.8% w/w) and xylans (16.4% w/w), which indicates the potential of J. curcas shells and husks for production of ethanol, xylitol and other glucose- and xylose-derived products. Acid hydrolysis was applied to a mixture of shells and husks under different sulphuric acid concentrations (from 0.5 to 4.5%), temperatures (170 – 220ºC) and time (10 – 20 min), and the hydrolytic conversion of xylan was evaluated. A zone of experimental conditions giving maximal xylan conversion was identified at around 4% H2SO4, 180ºC and reaction time below 10 min.

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.

Processes for production of ethanol and biogas (scenario 1) and biomethane (scenario 2) from pinewood improved by N - methyl morpholine - N - oxide ( NMMO) pretreatnment were developed and simulated by Aspen plus®.These processes were compared with t wo processes using steam explosion instead of N - methyl morpholine - N - oxide ( NMMO) pretreatment for production of ethanol (scenario 3) and biomethane (scenario 4), and the econom ies of these four processes were evaluated by Aspen Process Economic Analyzer ( PEA ). The gasoline equivalent prices of the products including 25% value added tax ( VAT ) and selling and distribution expenses for the scenarios 1 to 4 were respectively 1.40, 1 .20, 1.24, and 1.04 €/l, which are lower than gasoline price (1.65 €/l average in 2013 in Sweden). The profitability indexes for the scenarios 1 to 4 were 1.14, 0.93, 1.16, and 0.96 , respectively. Despite the lower manufacturing costs of biomethane, the pr ofitability indexes of these processes were lower than that of the bioethanol processes, because of higher capital requirements. The results showed that taxing rule is an effective parameter on the economy of the biofuels. The gasoline equivalent prices of the biofuels were 18 - 39% lower than gasoline; however, 37% of the gasoline price contributes to ene rgy and carbon dioxide tax which are not included in the prices of biofuels based on the Swedish taxation rules .

N-Methyl morpholine-N-oxide (NMMO) is an environmentally friendly and commercially applied cellulose solvent that is suggested for pretreatment of lignocelluloses to improve biofuel productions. However, the underlying mechanisms of the improvements have been poorly understood yet. In an attempt to investigate the mechanisms, pinewood powder and chips were pretreated with 85% (w/w) NMMO at 120°C for 1–15 h. The pretreatment improved ethanol production yield from 7.2% (g/g) for the untreated wood powder to 68.1–86.1% (g/g) and from 1.7% (g/g) for the untreated wood chips to 12.6–51.2% (g/g) of theoretical yield. Similarly, the biogas yields of untreated wood chips and powder were improved from 21 and 66 (mL/g volatile solids) by 3.5–6.8- and 2.6–3.4-folds, respectively. SEM micrographs indicated major increase in the wood porosity by the pretreatment, which would confirm increase in the water swelling capacity as well as enzyme adsorption. The analysis of X-ray diffraction showed considerable reduction in the cellulose crystallinity by the pretreatment, while FTIR spectroscopy results indicated reduction of lignin on the wood surface by the pretreatment.

Partial purification of glucoamylase from solid-state fermentation culture was, firstly, investigated by reverse micellar extraction (RME). To avoid back extraction problems, the glucoamylase was kept in original aqueous phase, while the other undesired proteins/enzymes were moved to reverse micellar organic phase. The individual and interaction effects of main factors, i.e. pH and NaCl concentration in aqueous phase, and concentration of AOT (sodium bis-2-ethyl-hexyl-sulphosuccinate) in organic phase were studied using response surface methodology. The optimum conditions for the maximum recovery of the enzyme were pH 2.75, 100 mM NaCl, and 200 mM AOT. Furthermore, the optimum organic to aqueous volume ratio (Vorg/Vaq) and appropriate number of sequential extraction stages were 2 and 3, respectively.Finally, 60% of the undesired enzymes including proteases and xylanases were removed from aqueous phase, while 140% of glucoamylase activity was recovered in aqueous phase and the purification factor of glucoamylase was found to be 3.0-fold.