Enrichment of a continuous culture of Saccharomyces cerevisiae with the yeast Issatchenkia orientalis in the production of ethanol at increasing temperatures.

摘要: A fermentation system was continuously fed with sugar-cane syrup and operated recycling of Saccharomyces cerevisiae cells at temperatures varying from 30 to 47°C. The aim the present work obtain study colonies isolates showing elongated yeasts which were sporadically observed end this continuous process. Based on a sequence assays involving methods classical taxonomy RAPD-PCR, two groups characteristics non-Saccharomyces identified in yeast population where S.cerevisiae dominant yeast. largest group yeasts, resulting slow proliferation over 2 months, reached final level 29.6% RAPD-PCR profiles obtained for indicated that they Issatchenkiaorientalis. Pichia membranifaciens only species detected together I. orientalis but very low frequency. optimum temperature ethanol formation shown by isolate 195B 42°C. This strain also showed faster biomass accumulation than thermotolerant S. used as starter Some able grow better 40°C 30°C plates containing glycerol carbon source. Yeasts produce high can extend process beyond limits tolerated cerevisiae.