Production of ethanol from biomasses. Part V Preparation and application of Trichoderma reesei mutants with enhanced .BETA.-glucosidase.

Kawamori, Mikio; Ado, Yutaka; Takasawa, Seigo

doi:10.1271/bbb1961.50.2477

Cited by 19 publications

(3 citation statements)

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“…This problem can be alleviated by addition of exogenous p-gtucosidase (Allen and Sternberg. 1980) or generation of [1-glucosidase overproducing strains by standard mutagenesis (Kawamori et aL, 1986) or recombinant techniques (Barnett ef a/., 1991), Some information is also available on the regulation of (i-glucosidase formation Sternberg and Mandels, 1982;Mishra et ai., 1989: Strauss andKubicek. 1990).…”

Section: Introductionmentioning

confidence: 99%

The bgl1 gene of Trichoderma reesei QM 9414 encodes an extracellular, cellulose‐inducible β‐glucosidase involved in cellulase induction by sophorose

Mach

Schink

Myasnikov³

et al. 1995

Molecular Microbiology

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We have investigated the effect of disruption of the bgl1-(beta-glucosidase l-encoding) gene of Trichoderma reesei on the formation of other beta-glucosidase activities and on the induction of cellulases. To this end the bgl1 locus was disrupted by insertion of the Aspergillus nidulans amdS (acetamidase-encoding) gene. The bgl1-disrupted strain did not produce the 75 kDa extracellular beta-glucosidase on cellulose or lactose, but still formed beta-glucosidase activity on glucose, cellobiose, xylan or beta-1,3-glucan, suggesting that the enzyme(s) exhibiting this beta-glucosidase activity is (are) not encoded by bgl1. The cellulase-inducer sophorose induced the bgl1-encoded beta-glucosidase, whereas the remaining beta-glucosidase activity was induced by methyl-beta-D-glucoside. The bgl1-gene product was mainly secreted into the medium, whereas the other beta-glucosidase activity was mainly associated with the cells. A bgl1-multicopy strain formed higher amounts of cellulases than the parent strain. Nonsaturating concentrations of sophorose efficiently induced cellobiohydrolase l formation in the bgl1-multicopy strain, but less efficiently in the bgl1-disrupted strain. The multicopy strain and the parent strain were comparably efficient at saturating sophorose concentrations. The beta-glucosidase inhibitor nojirimycin strongly inhibited induction in all strains. These data suggest that the bgl1-encoded beta-glucosidase is not identical to the plasma-membrane-bound, constitutive, methyl-beta-glucoside inducible beta-glucosidase, but represents an extracellular cellulose-induced enzyme. Both enzymes contribute to rapid induction of cellulases by modifying the inducer sophorose.

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Section: Introductionmentioning

confidence: 99%

The bgl1 gene of Trichoderma reesei QM 9414 encodes an extracellular, cellulose‐inducible β‐glucosidase involved in cellulase induction by sophorose

Mach

Schink

Myasnikov³

et al. 1995

Molecular Microbiology

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“…Both genes share a common intergenic upstream activation sequence (UAS) region whose activation results in the coordinate expression of MALT and MALS (39). Thus, glucose plays two roles in maltose utilization: it interferes with induction of the MAL transcriptional activator by maltose and it represses the expression of the permease and the maltase (12,14,20).2-Deoxy-D-glucose (DOG), a toxic glucose analog, has frequently been used to isolate glucose-deregulated mutants (19,21,22,38,40). Mutants isolated in galactose and DOG from industrial S. cerevisiae strains ferment equimolar mixtures of glucose and galactose to ethanol rapidly and completely (2) and have altered sugar transport activity (29,32).…”

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confidence: 99%

“…2-Deoxy-D-glucose (DOG), a toxic glucose analog, has frequently been used to isolate glucose-deregulated mutants (19,21,22,38,40). Mutants isolated in galactose and DOG from industrial S. cerevisiae strains ferment equimolar mixtures of glucose and galactose to ethanol rapidly and completely (2) and have altered sugar transport activity (29,32).…”

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confidence: 99%

Improved Properties of Baker's Yeast Mutants Resistant to 2-Deoxy- d -Glucose

Rincón

Codón

Castrejón

et al. 2001

Appl Environ Microbiol

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We isolated spontaneous mutants from Saccharomyces cerevisiae (baker's yeast V1) that were resistant to 2-deoxy-D-glucose and had improved fermentative capacity on sweet doughs. Three mutants could grow at the same rate as the wild type in minimal SD medium (0.17% Difco yeast nitrogen base without amino acids and ammonium sulfate, 0.5% ammonium sulfate, 2% glucose) and had stable elevated levels of maltase and/or invertase under repression conditions but lower levels in maltose-supplemented media. Two of the mutants also had high levels of phosphatase active on 2-deoxy-D-glucose-6-phosphate. Dough fermentation (CO 2 liberation) by two of the mutants was faster and/or produced higher final volumes than that by the wild type, both under laboratory and industrial conditions, when the doughs were supplemented with glucose or sucrose. However, the three mutants were slower when fermenting plain doughs. Fermented sweet bakery products obtained with these mutants were of better quality than those produced by the wild type, with regard to their texture and their organoleptic properties.Saccharomyces cerevisiae may utilize a variety of carbon sources, but glucose and fructose are preferred. When one of these sugars is present, carbon catabolite repression occurs and the enzymes required for utilization of the alternative carbon sources are synthesized at low rates or not at all (12,13,14). Carbon catabolite repression alters transcription and is regulated mainly by the Mig1p protein (13, 14, 23), a transcriptional repressor of glucose-repressible genes involved in metabolic processes other than glucose fermentation (such as utilization of the alternative carbon sources sucrose, maltose, or galactose; gluconeogenesis; and respiratory metabolism [13,14]). Transcription of genes required for growth in nonfermentable carbon sources is activated by the Hap complex, which is repressed by Mig1p (5,14).S. cerevisiae baker's yeasts commonly are grown in molasses, which contains sucrose as the primary carbon source, and genotypes with the highest growth rate and productivity in molasses are favored (8,9,10,11). Further increases in invertase expression and redirection of the respiro-fermentative flux through the deregulation of Mig1p or Hap complex (5) would improve utilization of molasses and production of sweet doughs by these strains. Expression of the SUC genes, which code for the invertase required for catabolism of sucrose and raffinose, is repressed at high levels of glucose (12,13,14). Various regulatory regions have been identified in the SUC2 promoter. Mig1p binds to SUC2A and SUC2B (activation sequences) in the presence of glucose. Repression mediated by the upstream repression sequence for SUC2 (URS SUC2 ) occurs in the absence of glucose (14).In dough without addition of sugar, the principal fermentable sugar for yeast is maltose, liberated from the starch of the flour by amylases. The leavening ability of sponge dough is closely related to maltose fermentability (4,20). Maltose utilization requires a MAL locus and tr...

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Variation in cellulase‐constituting components from Trichoderma reesei with agitation intensity

Mukataka

Kobayashi

Sato

et al. 1988

Biotech & Bioengineering

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Cellulase producing activity of Trichoderma reesei QM9414 was examined under various agitation intensities and at the dissolved oxygen concentration above 3 ppm. The producing activity greatly depended upon the agitation intensity, and the dependence on the agitation was different for each cellulase-constituting component. The maximum producing activities of FPA, CM Case, and beta-glucosidase were obtained under different agitation conditions, 1.0, 0.7, and 1.4 m/s in tip velocity, respectively. Intensive agitation brought about remarkable reduction in all cellulase components. The mycelial transformation through agitation intensity was also observed. Comparatively mild agitation of 0.3-1.0 m/s caused pellet formation as the culture progressed, although the pelletization was delayed with increasing agitation intensity. The behavior of the pelletization did not occur at 1.3 and 1.7 m/s throughout the course of cultivation, and under the latter agitation condition hyphae were broken up into short fragments. The cellulase producing activity is discussed in relation to such morphological changes.

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Production of ethanol from biomasses. Part V Preparation and application of Trichoderma reesei mutants with enhanced .BETA.-glucosidase.

Cited by 19 publications

References 1 publication

The bgl1 gene of Trichoderma reesei QM 9414 encodes an extracellular, cellulose‐inducible β‐glucosidase involved in cellulase induction by sophorose

The bgl1 gene of Trichoderma reesei QM 9414 encodes an extracellular, cellulose‐inducible β‐glucosidase involved in cellulase induction by sophorose

Improved Properties of Baker's Yeast Mutants Resistant to 2-Deoxy- d -Glucose

Variation in cellulase‐constituting components from Trichoderma reesei with agitation intensity

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