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Upcycle of co-products from corn–ethanol plant into protein-rich animal feed with balanced key amino acids via solid-state fermentation is a promising approach to economically support both biofuel and animal feed industries. However, there are multiple types of solid-state fermentation microorganisms and growth conditions that have not been tested. In this study, Mucor indicus and Rhizopus oryzae were used to ferment corn-based wet distiller’s grains with solubles (WDGS). The effects of fermentation conditions (temperature, agitation, and moisture) and supplementations (extraneous carbon and nitrogen sources) were evaluated on protein production and amino acids profiles before and after fermentation. The study established best fermentation conditions (23 °C, static incubation for 4 days at 70% initial moisture content) to improve protein content for both R. oryzae and M. indicus. Moreover, urea supplied to R. oryzae and M. indicus improved protein concentration by 35 and 38%, and total amino acids content by 28 and 18%, respectively. The amount of 693.1 and 451.8 mg of additional total amino acids including 262.8 and 227.7 mg of key amino acids (lysine, methionine, tryptophan, and arginine) was synthesized by R. oryzae and M. indicus, respectively, per supply of 536 mg urea in 25 g of WDGS. This study demonstrated the feasibility of urea as a low-cost nitrogen source for amino acid biosynthesis in fungal fermentation of WDGS, which could contribute to the increasing demand for high-value monogastric animal feed.

Dissolution of lignocelluloses in N-methylmorpholine-N-oxide (NMMO or NMO) at moderate conditions, e.g., 120 °C for 3 h under atmospheric pressure, and regeneration with water, is among the most effective nonderivatization pretreatment for the improvement of enzymatic hydrolysis and ethanol production. The effects of the pretreatment on two different types of wood, hardwood elm and softwood pine, were compared via physicochemical structural analyses, i.e., FTIR, XRD, SEM, TGA, and enzyme adsorption techniques, to relate their properties to the extent of enzymatic conversion. After the pretreatment, cellulose was highly recovered and characterized to be mainly cellulose II and amorphous cellulose, with lower cellulose crystallinity index, higher thermal stability, and more favorable surface features for hydrolysis, compared to native woods. Moreover, the strength of enzyme binding onto the lignocelluloses, which was directly related to the enzymatic hydrolysis rate, increased by 57% and 164% for pinewood and elmwood, respectively. The highest total reducing sugars yield for untreated pinewood was 9.8% (74 mg/g-substrate) and improved to 58.5% (330 mg/g-substrate) after the pretreatment, whereas the corresponding values for elmwood were 14.7% (104 mg/g-substrate) vs. 51.4% (274 mg/g-substrate). Furthermore, maximum ethanol theoretical yields of 63.5 and 41.4% were obtained from pinewood and elmwood by Saccharomyces cerevisiae and Mucor indicus, respectively.

The pulverized A. cosmosus peel was found to contain 25 ± 0.31 % cellulose, 28 ± 0.18 % hemicellulose and 8 ± 0.07 % of lignin on dry solid basis. 1 % H2SO4 delignified A. cosmosus peel yielded 38.81 % xylose, 29.31 % fructose and 18.89 % glucose under steam explosion, with a hydrolytic efficiency of 75.52 %. Fourier transform infrared spectroscopy results not only indicated the penetration of H2SO4 in the amorphous region of the biomass and degradation of hemicelluloses but also shows the structural differences before and after pretreatment. Simultaneous Saccharification and Fermentation of pretreated A. cosmosus peel by cellulase and Mucor indicus MTCC 4349 were investigated in the present study. Important process variables for ethanol production from pretreated A. cosmosus peel were optimized using Response Surface Methodology (RSM) based on central composite design (CCD) experiments. A three level CCD experiments with central and axial points was used to develop a statistical model for the optimization of process variables such as incubation temperature (30, 32 and 34 °C) X1, inoculum level (2, 4 and 6 %) X2 and nutrients (1/2/3) X3. Data obtained from RSM on ethanol production were subjected to the analysis of variance and analyzed using a second order polynomial equation and contour plots were used to study the interactions among three relevant variables of the fermentation process. The fermentation experiments were carried out at flask level. The processing parameters setup for reaching a maximum response for ethanol production was obtained when applying the optimum values for temperature (30 °C), inoculum level (2 %) and fermentation medium (urea, NaH2PO4, tryptone and meat extract) for Mucor indicus MTCC 4349. Maximum ethanol concentration 10.4293 g/l was obtained after 72 h from Mucor indicus MTCC 4349 at the optimized process conditions in aerobic batch fermentation.

Buckwheat tea waste (BWTW) and barley tea waste (BTW), by-products of the beverage industry, are alternative carbohydrate sources for ethanol production. In this study, optimal enzyme loading for enzymatic saccharification of BWTW and BTW was determined, and simultaneous saccharification and fermentation (SSF) was performed by Saccharomyces cerevisiae and Mucor indicus to produce ethanol. Optimal enzyme loading for enzymatic saccharification of 2 % w/v BWTW and BTW was 0.5 % (weight of enzyme/weight of tea wastes) for BWTW and 0.1 % for BTW. Ethanol production from BWTW by S. cerevisiae and M. indicus after 48 h of SSF was 49.9/100 g of BWTW and 47.9/100 g of BWTW, respectively, with 0.5 % enzyme loading. Ethanol production from BTW by S. cerevisiae and M. indicus after 48 h of SSF was 20.5/100 g of BTW and 21.6/100 g of BTW, corresponding to 62 and 66 % of the theoretical yield based on starch content, respectively, with 0.1 % of enzyme loading. Furthermore, S. cerevisiae produced 76 % of the theoretical yield based on the total glucose from starch in BWTW and BTW when a mixture of BWTW and BTW was used as a substrate, with 0.2 % enzyme loading and no additional nitrogen or mineral sources.

Mucor indicus can be used to produce ethanol from a variety of sugars, including pentose's. An extract of it, produced by autolysis, could replace yeast extract in culture medium with improved production of ethanol. At 10 g l(-1), the extract gave a higher ethanol yield (0.47 g g(-1)) and productivity (0.71 g l(-1) h(-1)) compared to medium containing yeast extract (yield 0.45 g g(-1); productivity 0.67 g l(-1) h(-1)).

In this study Banh mensamples obtained from Vietnam were analysed in terms of pH, moisture content and fungal composition. The banh men pH proved to be acidic with a mean pH of 5.76. Moisture content was 13.6%. Total mould and yeast counts yielded 1.3 × 106 and 4.3 × 106 c.f.u./g-fresh sample, respectively. A total of 53 fungal isolates were obtained from 20 moulds and 33 yeasts. The mould isolates were identified as Rhizopus oryzae, Mucor indicus, Mucor circinilloides, and Amylomyces rouxii. The yeast isolates were identified as Saccharomyces cerevisiae, Hyphopichia burtonii, Saccharomycopsis fibuligera, Pichia anomala, and Candida sp. Based on the parameters used in this study, it can be deduced that banh men is similar to ragi and other Asian fermentation starters.