Effect of xylose and nutrients concentration on ethanol production by a newly isolated extreme thermophilic bacterium

摘要

An extreme thermophilic ethanol-producing strain was isolated from an ethanol high-yielding mixednculture, originally isolated from a hydrogen producing reactor operated at 70 WnC. Ethanol yields werenassessed with increasing concentrations of xylose, up to 20 g/l. The ability of the strain to grownwithout nutrient addition (yeast extract, peptone and vitamins) was also assessed. The maximumnethanol yield achieved was 1.28 molethanoln/molxylose consumed (77% of the theoretical yield), at 2 g/l ofninitial xylose concentration. The isolate was able to grow and produce ethanol as the mainnfermentation product under most of the conditions tested, including in media lacking vitamins,npeptone and yeast extract. The results indicate that this new organism is a promising candidate fornthe development of a second generation bio-ethanol production process.