Lopes Daiane Dias, Rosa Carlos Augusto, Hector Ronald E, Dien Bruce S, Mertens Jeffrey A, Ayub Marco Antônio Záchia
Biotechnology and Biochemical Engineering Laboratory (BiotecLab), Federal University of Rio Grande do Sul, Av. Bento Gonçalves, 9500, PO Box 15090, Porto Alegre, RS, 91501-970, Brazil.
Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, Brazil.
J Ind Microbiol Biotechnol. 2017 Nov;44(11):1575-1588. doi: 10.1007/s10295-017-1979-z. Epub 2017 Sep 11.
An industrial ethanol-producing Saccharomyces cerevisiae strain with genes of fungal oxido-reductive pathway needed for xylose fermentation integrated into its genome (YRH1415) was used to obtain haploids and diploid isogenic strains. The isogenic strains were more effective in metabolizing xylose than YRH1415 strain and able to co-ferment glucose and xylose in the presence of high concentrations of inhibitors resulting from the hydrolysis of lignocellulosic biomass (switchgrass). The rate of xylose consumption did not appear to be affected by the ploidy of strains or the presence of two copies of the xylose fermentation genes but by heterozygosity of alleles for xylose metabolism in YRH1415. Furthermore, inhibitor tolerance was influenced by the heterozygous genome of the industrial strain, which also showed a marked influenced on tolerance to increasing concentrations of toxic compounds, such as furfural. In this work, selection of haploid derivatives was found to be a useful strategy to develop efficient xylose-fermenting industrial yeast strains.
一株工业乙醇生产酿酒酵母菌株（YRH1415），其基因组整合了木糖发酵所需的真菌氧化还原途径基因，用于获得单倍体和二倍体同基因菌株。同基因菌株在代谢木糖方面比YRH1415菌株更有效，并且能够在存在由木质纤维素生物质（柳枝稷）水解产生的高浓度抑制剂的情况下共同发酵葡萄糖和木糖。木糖消耗速率似乎不受菌株倍性或木糖发酵基因两份拷贝的存在影响，而是受YRH1415中木糖代谢等位基因的杂合性影响。此外，抑制剂耐受性受工业菌株杂合基因组影响，这也对其对不断增加浓度的有毒化合物（如糠醛）的耐受性有显著影响。在这项工作中，发现选择单倍体衍生物是开发高效木糖发酵工业酵母菌株的有用策略。
