Isolation and characterization of a mutant recombinant Saccharomyces cerevisiae strain with high efficiency xylose utilization

摘要: A recombinant xylose-utilizing Saccharomyces cerevisiae strain carrying one copy of heterologous XYL1 and XYL2 from Pichia stipitis endogenous XKS1 under the control TDH3 promoter in chromosomal DNA was constructed industrial haploid yeast NAM34-4C, which showed thermotolerance acid tolerance. The S. cerevisiae SCB7 grew minimal medium containing xylose as sole carbon source, its shortest generation time (Gshort) 5 h. From this strain, four mutants showing rapid growth (Gshort = 2.5 h) were isolated. carried mutations that classified into three linkage groups. Three dominant mutation recessive to wild type allele. PHO13 gene encoding para-nitrophenyl phosphatase. other mutant genes not linked TAL1 transaldolase. When their parental used for batch fermentation a complex at pH 4.0 30 g/L 35°C with shaking (60 rpm) an initial cell density (Absorbance 660 nm) 1.0, all efficient ethanol production consumption early stage culture. In two mutants, within 24 h, 4.8 g/L produced, yield 47%, 1.4 times higher than achieved strain. concentration decreased linearly rate 1 g/L/h until 24 h.