Xylitol Production by Genetically Engineered Trichoderma reesei Strains Using Barley Straw as Feedstock

Dashtban, Mehdi; Kepka, Greg; Schink, Bernhard; Qin, Wensheng

doi:10.1007/s12010-012-0008-y

Cited by 30 publications

(13 citation statements)

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“…As such a strong producer of cellulases and hemicellulases (a genome-wide search using the JGI Genome Portal (http://genome.jgipsf.org/Trire2/Trire2.home.html) revealed for T. reesei 10 celluloytic and 16 xylanolytic enzyme-encoding genes (Martinez et al [2008])) it is likely that T. reesei is able to grow on cheap biowaste material like wheat straw as the sole carbon source. This is supported by former reports on T. reesei capable of growing on lignocellulosic material (Acebal et al [1986]; Dashtban et al [2013]).…”

Section: Introductionsupporting

confidence: 83%

Erythritol production on wheat straw using Trichoderma reesei

2014

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We overexpressed the err1 gene in the Trichoderma reesei wild-type and in the cellulase hyperproducing, carbon catabolite derepressed strain Rut-C30 in order to investigate the possibility of producing erythritol with T. reesei. Two different promoters were used for err1 overexpression in both strains, a constitutive (the native pyruvat kinase (pki) promoter) and an inducible one (the native β-xylosidase (bxl1) promoter). The derived recombinant strains were precharacterized by analysis of err1 transcript formation on D-xylose and xylan. Based on this, one strain of each type was chosen for further investigation for erythritol production in shake flasks and in bioreactor experiments. For the latter, we used wheat straw pretreated by an alkaline organosolve process as lignocellulosic substrate. Shake flask experiments on D-xylose showed increased erythritol formation for both, the wild-type and the Rut-C30 overexpression strain compared to their respective parental strain. Bioreactor cultivations on wheat straw did not increase erythritol formation in the wild-type overexpression strain. However, err1 overexpression in Rut-C30 led to a clearly higher erythritol formation on wheat straw.

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Section: Introductionsupporting

confidence: 83%

Erythritol production on wheat straw using Trichoderma reesei

2014

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“…From the SEM results it can be inferred that recombinant T/ Ace2-2 strain could successfully disrupt the intricate lignocellulosic networks and utilize hemicellulose and cellulosic units for its growth and metabolism and the xylitol production yields also confirm this fact. Dashtban et al [59] have conducted double gene deletion experiments with xylitol dehydrogenase and l -arabinitol-4-dehydrogenase to breakdown the preprocessed barley straw for the production of xylitol [59]. The maximum xylitol production yield reported by Dashtban et al was 13.2 g/l, which was higher than the xylitol conversion efficiency of our study.…”

Section: Discussioncontrasting

confidence: 64%

The ACEII recombinant Trichoderma reesei QM9414 strains with enhanced xylanase production and its applications in production of xylitol from tree barks

et al. 2016

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BackgroundACEII transcription factor plays a significant role in regulating the expression of cellulase and hemicellulase encoding genes. Apart from ACEII, transcription factors such as XYR1, CRE1, HAP2/3/5 complex and ACEI function in a coordinated pattern for regulating the gene expression of cellulases and hemicellulases. Studies have demonstrated that ACEII gene deletion results in decreased total cellulase and xylanase activities with reduced transcript levels of lignocellulolytic enzymes.ResultsIn this study, we have successfully transformed the ACEII transcription factor encoding gene in Trichoderma reesei to significantly improve its degrading abilities. Transformation experiments on parental strain T. reesei QM9414 has resulted in five genetically engineered strains T/Ace2-2, T/Ace2-5, T/Ace2-8, T/Ace5-4 and T/Ace10-1. Among which, T/Ace2-2 has exhibited significant increase in enzyme activity by twofolds, when compared to parental strain. The T/Ace2-2 was cultured on growth substrates containing 2% bark supplemented with (a) sugar free + MA medium (b) glucose + MA medium and (c) xylose + MA medium. The bark degradation efficiency of genetically modified T/Ace2-2 strain was assessed by analyzing the xylitol production yield using HPAEC. By 6th day, about 10.52 g/l of xylitol was produced through enzymatic conversion of bark (2% bark + MA + xylose) by the T/Ace2-2 strain and by 7th day the conversion rate was found to be 0.21 g/g. Obtained results confirmed that bark growth medium supplemented with d-xylose has profoundly increased the conversion rate of bark by T/Ace2-2 strain when compared to sugar free and glucose supplemented growth media. Results obtained from scanning electron microscopy has endorsed our current results. Bark samples inoculated with T/Ace2-2 strain has showed large number of degraded cells with clearly visible cavities and fractures, by exposing the microfibrillar interwoven complex.ConclusionWe propose a cost effective and ecofriendly method for the degradation of lignocellulosic biomass such as bark to produce xylitol by using genetically modified T. reesei. Efficient conversion rate and production yield obtained in our current study provides a great scope for the xylitol industries, as our method bypasses the pretreatment of bark achieving clean and low-cost xylitol production.

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“…Yeastscan only use biomass hydrolysates to produce xylitol or to ferment biomass with other microorganisms to produce xylitol. In contrast, genetically engineered T. reesei strains can use biomass directly to produce xylitol [18]. Additionally, T. reesei grows rapidly and there is no need for strict control of growth conditions, ultimately lowering xylitol production costs compared to the use of yeast strains.…”

Section: Discussionmentioning

confidence: 99%

Overexpression of D-Xylose Reductase (xyl1) Gene and Antisense Inhibition of D-Xylulokinase (xyiH) Gene Increase Xylitol Production inTrichoderma reesei

Yang

Dashtban

Kepka

et al. 2014

BioMed Research International

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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.

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Xylitol Production by Genetically Engineered Trichoderma reesei Strains Using Barley Straw as Feedstock

Cited by 30 publications

References 30 publications

Erythritol production on wheat straw using Trichoderma reesei

Erythritol production on wheat straw using Trichoderma reesei

The ACEII recombinant Trichoderma reesei QM9414 strains with enhanced xylanase production and its applications in production of xylitol from tree barks

Overexpression of D-Xylose Reductase (xyl1) Gene and Antisense Inhibition of D-Xylulokinase (xyiH) Gene Increase Xylitol Production inTrichoderma reesei

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