Utilization of hydrothermally pretreated wheat straw for production of bioethanol and carotene-enriched biomass

In this work hydrothermally pretreated wheat straw was used for production of bioethanol by Saccharomyces cerevisiae and carotene-enriched biomass by red yeasts Rhodotorula glutinis, Cystofilobasidium capitatum and Sporobolomyces roseus. To evaluate the convertibility of pretreated wheat straw into ethanol, simultaneous saccharification and fermentation of S. cerevisiae was performed under semi-anaerobic conditions. The highest ethanol production efficiency of 65-66% was obtained following pretreatment at 200°C without the catalytic action of acetic acid, and at 195 and 200°C respectively in the presence of catalyst. Red yeast strain S. roseus produced 1.73-2.22mgg^-1 of ergosterol on the filter cake, 1.15-4.17mgg^-1 of ergosterol and 1.23-1.56mgg^-1 of β-carotene on pretreated wheat straw hydrolysates and also the highest amount of carotenoids and ergosterol on untreated wheat straw (1.70 and 4.17mgg^-1, respectively).