Overexpression of D-xylose reductase (xyl1) gene and antisense inhibition of D-xylulokinase (xyiH) gene increase xylitol production in Trichoderma reesei.
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ABSTRACT: T. reesei is an efficient cellulase producer and biomass degrader. To improve xylitol production in Trichoderma reesei strains by genetic engineering, two approaches were used in this study. First, the presumptive D-xylulokinase gene in T. reesei (xyiH), which has high homology to known fungi D-xylulokinase genes, was silenced by transformation of T. reesei QM9414 strain with an antisense construct to create strain S6-2-2. The expression of the xyiH gene in the transformed strain S6-2-2 decreased at the mRNA level, and D-xylulokinase activity decreased after 48?h of incubation. This led to an increase in xylitol production from undetectable levels in wild-type T. reesei QM9414 to 8.6?mM in S6-2-2. The T. reesei ?xdh is a xylose dehydrogenase knockout strain with increased xylitol production compared to the wild-type T. reesei QM9414 (22.8?mM versus undetectable). The copy number of the xylose reductase gene (xyl1) in T. reesei ?xdh strain was increased by genetic engineering to create a new strain ?9-5-1. The ?9-5-1 strain showed a higher xyl1 expression and a higher yield of xylose reductase, and xylitol production was increased from 22.8?mM to 24.8?mM. Two novel strains S6-2-2 and ?9-5-1 are capable of producing higher yields of xylitol. T. reesei has great potential in the industrial production of xylitol.
SUBMITTER: Hong Y
PROVIDER: S-EPMC4071787 | biostudies-literature | 2014
REPOSITORIES: biostudies-literature
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