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Bio-ethanol used today is mainly produced from sugar cane and cereals, but reducing the production costs of ethanol is still crucial for a viable economic process. Cellulose from plant biomass will be the next cheaper raw material for second generation fuel ethanol production. Saccharomyces cerevisiae and Schizosaccharomyces pombae are the common industrial yeast strains used for the production of ethanol from various substrates derived from agricultural commodities. In the present study, ethanol was produced from various substrates such as molasses, sugarcane juice, sugarcane syrup, jaggery, grapes, beet root, orange and rice substrates by using Saccharomyces cerevisiae and Schizosaccharomyces pombae. The experimental study shows that the biomass production declines progressively when the ethanol accumulates in the surrounding medium after the production of ethanol. However, the conversion of ethanol was achieved in batch fermentation process at optimum temperature and the internal pH of the fermentation medium at laboratory level. The yield percentage of ethanol for the above substrates were analyzed and compared for different carbon sources. Among different substrates, Jaggery and Molases showed higher ethanol yield as 95.2% and 93.5% respectively. Among the two species of yeast studied, Saccharomyces cerevisiae yielded higher percentage of ethanol than Schizosaccharomyces pombae in batch fermentation process. The present study concludes the effect of various carbon sources on production of ethanol with two different industrial yeast strains such as Saccharomyces cerevisiae and Schizosaccharomyces pombae are vary in similar conditions of ethanol production processprocess. [ABSTRACT FROM AUTHOR]

Xylose is abundant in lignocellulosic biomass. The fermentation of xylose is still a key problem in cellulose ethanol fermentation. In this research, the xylose fermentation strains were isolated from the soil sample. Strain N6 was chosen for further xylose fermentation experiments. Comparison of its 16S rDNA gene sequence with available sequences in GenBank showed that it was 100 % identical to that of Bacillus cereus strain SWFU2816 (Accession No. JN935015.1). Strain N6, which ferments xylose and hexose to ethanol, can produce fuel ethanol. The ability of strain N6 to transform xylose was better than its ability to transform glucose. As a result, the optimal condition for xylose fermentation was determined. The optimum fermentation conditions at 150 rpm for 48 h in a shake flask were as follows: pH 7.0, reducing sugar 70 g L-1, inoculation amount 5 %, and temperature 38 °C. The xylose to ethanol yield coefficient could reach a maximum of 0.26 g g-1. At the same time, the influence of the acid hydrolysis by-products on the isolated strain was studied. Compared to the commonly used saccharomycetes, the tolerance of strain N6 on furaldehyde had greatly improved, which could help ethanol fermentation from lignocellulose materials. [ABSTRACT FROM AUTHOR]

Abstract: A two-stage fermentation process, consisting of a simultaneous saccharification and fermentation (SSF) stage and a dry methane fermentation stage, was developed to utilize garbage for the production of fuel ethanol and methane. Garbage from families, canteens and concessionaires was used for the study. Saccharification method was studied and the results indicated that the liquefaction pretreatment and the combination of cellulase and glucoamylase was effective for polysaccharide hydrolysis of family garbage with a high content of holocellulose and that SSF was suitable for ethanol fermentation of garbage. Ethanol productivity could be markedly increased from 1.7 to 7.0 g/l/h by repeated-batch SSF of family garbage. A high ethanol productivity of 17.7 g/l/h was achieved when canteen garbage was used. The stillage after distillation was treated by dry methane fermentation and the results indicated that the stillage was almost fully digested and that about 850 ml of biogas was recovered from 1 g of volatile total solid (VTS). Approximately 85% of the energy of the garbage was converted to fuels, ethanol and methane by this process. [Copyright &y& Elsevier]