title: Overexpression of D-xylose reductase (xyl1) gene and antisense inhibition of D-xylulokinase (xyiH) gene increase xylitol production in Trichoderma reesei.
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 Δxdh 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 Δxdh strain was increased by genetic engineering to create a new strain Δ9-5-1. The Δ9-5-1 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 Δ9-5-1 are capable of producing higher yields of xylitol. T. reesei has great potential in the industrial production of xylitol.
authors.affiliation: Department of Biology, Lakehead University, Thunder Bay, ON, Canada P7B 5E1 ; State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Hong
authors.affiliation: Department of Biology, Lakehead University, Thunder Bay, ON, Canada P7B 5E1 ; School of Environmental Sciences, University of Guelph, Guelph, ON, Canada N1G 2W1.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Dashtban
authors.affiliation: Department of Biology, Lakehead University, Thunder Bay, ON, Canada P7B 5E1 ; Instrumentation Laboratory, Lakehead University, 955 Oliver Road, Thunder Bay, ON, Canada P7B 5E1.
authors.forename: Greg
authors.initials: G
authors.lastname: Kepka
authors.affiliation: State Key Laboratory for Agrobiotechnology and College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Sanfeng
authors.initials: S
authors.lastname: Chen
authors.affiliation: Department of Biology, Lakehead University, Thunder Bay, ON, Canada P7B 5E1.
authors.forename: Wensheng
authors.initials: W
authors.lastname: Qin
mesh_terms: D005285:Fermentation; D015966:Gene Expression Regulation, Fungal; D005818:Genetic Engineering; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics* / Q000378:metabolism; D014242:Trichoderma / Q000201:enzymology / Q000235:genetics*; D014993:Xylitol / Q000096:biosynthesis*; D014994:Xylose / Q000378:metabolism
chemical_list: D014994:Xylose; D017853:Phosphotransferases (Alcohol Group Acceptor); C032700:xylulokinase; D014993:Xylitol