ABSTRACT
Yeast strains with improved ethanol yield are important for efficient bioconversion of lignocellulosic biomass for fuel ethanol.Candida shehatae CICC1766 was adapted to 4%(v/v)ethanol,and then subjected to UV mutagenesis.One respiration deficient mutant Rd-5 with improved xylose fermentation capability was selected.Protoplasts of Rd-5 were inactivated by UV treatment,followed by the PEG-mediated protoplast fusion with a Saccharomyces cerevisiae strain with good ethanol-fermenting capability.The xylose fermenting capability of the fusants was investigated,and the fusant F6 demonstrated good ethanol fermentation performance,producing 18.75g/L ethanol from 50g/L xylose with an ethanol yield of 0.375 or 73.4% of its theoretical value of 0.511.Comparing with its parent Candida shehatae strain,the ethanol yield of F6 was increased by 28%.