engleski

Kinetic analysis of genetically modified Saccharomyces cerevisiae cultivated on wheat straw hydrolisates

Wheat straw hydrolysates (obtained by diluted sulphuric acid pre-treatment) were used as substrates for anaerobic cultivation of genetically modified strain of Saccharomyces cerevisiae. Wheat straw pre-treatment process was carried out in the high-pressure reactor under different temperatures (150 - 200 °C) and retention times (1 - 10 min) with 0, 5 % w/w sulphuric acid. The highest mass fraction of xylans (68, 64 % w/w) in the wheat straw hydrolysate was observed at 160 °C and residence time of 5 minutes and the highest mass fraction of glucans (30, 42 % w/w) at 200 °C and residence time of 10 minutes, respectively. Genetically modified strain of Saccharomyces cerevisiae has ability to use hexoses and pentoses as a carbon source. The initial kinetic study (e.g. growth rate and ethanol synthesis) of modified yeast strain was carried out in small scale. The most successful ethanol production was observed on the wheat straw hydrolysates obtained at 180 °C and residence time of 10 minutes. In these conditions, bioethanol production efficiency was 43, 25 % and bioprocess productivity of 0, 045 g L-1 h-1, respectively. During anaerobic cultivation of genetically modified S. cerevisiae in the horizontal rotating tubular bioreactor on the same hydrolysate, bioprocess productivity was 0, 143 g L-1 and efficiency of 64, 01 %, respectively.

wheat straw ; hydrolysates ; Saccharomyces cerevisiae ; ethanol

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