Showing papers on "Trichoderma reesei published in 1982"
TL;DR: True cellulase activity has been demonstrated in cell-free preparations from the thermophilic anaerobe Clostridium thermocellum and the absence of substrate at temperatures up to 70 degrees C, carboxymethylcellulase was much more unstable than the Avicel-hydrolyzing activity.
Abstract: True cellulase activity has been demonstrated in cell-free preparations from the thermophilic anaerobe Clostridium thermocellum Such activity depends upon the presence of Ca and a thiol-reducing agent of which dithiothreitol is the most promising Under these conditions, native (cotton) and derived forms of cellulose (Avicel and filter paper) were all extensively solubilized at rates comparable with cellulase from Trichoderma reesei Maximum activity of the Clostridium cellulase was displayed at 70 degrees C and at pH 57 and 61 on Avicel and carboxymethylcellulose, respectively In the absence of substrate at temperatures up to 70 degrees C, carboxymethylcellulase was much more unstable than the Avicel-hydrolyzing activity
318 citations
TL;DR: The present result appear to imply that the role of enzyme–substrate complex formation should not be ignored in deriving a mechanistic kinetic model for enzymatic hydrolysis of cellulose.
Abstract: A study was conducted on the kinetics of enzymatic hydrolysis of pure insoluble cellulose using unpurified culture filtrate Trichoderma reesei, with the emphasis on the initial reaction period. The initial hydrolysis rate and extent of enzyme (soluble protein)adsorption, either apparent or initial, were evaluated under various experimental conditions. It has been found that the various mass-transfer steps do not control the overall hydrolysis rate and that the hydrolysis rate is mainly controlled by the surface reaction step promoted by the adsorbed enzyme. It has also been found that the initial hydrolysis rate strongly depends on the initial extent of soluble protein adsorption and the effectiveness of the adsorbed soluble protein to promote the hydrolysis. The initial extent of soluble protein adsorption, in turn, is related to the initial cellulose concentration, enzyme concentration, and specific surface area of cellulose, whereas the effectiveness of the initially adsorbed soluble protein to promote the derived to interrelate these parameters without resorting to the Michaelis-Menten kinetics. The present result appear to imply that the role of enzyme-substrate complex formation should not be ignored in deriving a mechanistic kinetic model for enzymatic hydrolysis of cellulose.
214 citations
TL;DR: HPLC‐analysis of the reaction products of a series of 4‐methylumbelliferyl glycosides from cello‐oligosaccharides, used as substrates of a cellobiohydrolase from Trichoderma reesei, proves the lack of specificity for terminal cellobiosyl groups.
183 citations
TL;DR: Compared with saccharisation in the absence of yeast, simultaneous saccharification and fermentation (SSF) using Trichoderma cellulases and Saccharomyces cerevisiae enhanced cellulose hydrolysis rates by 13–30%.
102 citations
TL;DR: A process regulating ER biogenesis may have been deactivated by mutation in RUT-C30 cells and thus the potential for extracellular enzyme synthesis and secretion has been enhanced.
65 citations
TL;DR: It is proved that 56V is as good a substrate as pure cellulose for enzyme production when the toxic and/or inhibitory compounds were removed by water washing.
53 citations
TL;DR: This work reports the isolation of a constitutively cellulase producing mutant in T. reesei that produces high levels of all of the component enzymes in the cellulase complex in the presence of glucose or sucrose.
Abstract: The single major factor limiting the economy of enzymatic hydrolysis of cellulose is the cost of the cellulase enzymes. Most of the work to date in reducing this cost has centered around selection of hyperproducing strains using the standard cellulose medium. Cellulose is an insoluble substrate with obvious design disadvantages in bioreactors. It is often indicated that another reasonable approach to the problem would be the isolation of constitutive mutants which require no inducer to form cellulase. In fact, the goal of several laboratories around the world working on the hydrolysis of cellulosic substances has been to isolate a constitutive mutant. Reported here is the isolation of a constitutively cellulase producing mutant in T. reesei that produces high levels of all of the component enzymes in the cellulase complex in the presence of glucose or sucrose. With this constitutive mutant, it is hoped that a major hurdle of working with an insoluble substrate will be overcome. The mutant will allow easier operation and control of cellulose bioreactors and can be used for continuous enzyme production, as opposed to the present batch production system. Also, a number of other unusable susbtrates like whey and molasses can be used for commercial preparationsmore » of cellulases. (Refs. 2).« less
48 citations
TL;DR: Cellulase production by Trichoderma reesei mutant RUT-C30, immobilized on 4% κ-carrageenan beads, was monitored in continuous culture for 13 days and carbon and nitrogen requirements were reduced to 1/4-1/2 those of conventional continuous culture.
Abstract: Cellulase production by Trichoderma reesei mutant RUT-C30, immobilized on 4% κ-carrageenan beads, was monitored in continuous culture for 13 days. Cellulase production averaged 26.0 Filter Paper Units (FPU)/l/hr; carbon and nitrogen requirements per FPU produced were reduced to 1/4-1/2 those of conventional continuous culture.
43 citations
TL;DR: A mutant, D1-6, was isolated and found to be a distinctly superior strain compared to QM 9414 and several other progenies of this parent and the note presents the possibilities of isolating not only hyperproducing strains but also those which are catabolic repression resistant.
Abstract: A short note on a strain improvement program of Trichoderma reesei QM 9414 initiated in 1976. A mutant, D1-6, was isolated and found to be a distinctly superior strain compared to QM 9414 and several other progenies of this parent. The note presents the possibilities of isolating not only hyperproducing strains but also those which are catabolic repression resistant. In fact, D1-6 is both a hyperproducer and a catabolite repression resistant mutant. (Refs. 7).
40 citations
TL;DR: The low, constitutive activity of β-glucosidase is more than adequate to theoretically account for respiration of the fungus on cellobiose, and is produced constitutively at low levels.
37 citations
01 Jan 1982
TL;DR: The cellulase enzyme system of Trichoderma reesei QM9414 was chosen for this study because it is famous for its ability to degrade highly crystalline cellulose and is one of the most efficient of the cellulolytic fungi.
Abstract: Cellulases have biological and economic significance in their destructive roles in plant pathogenesis (W. Brown, 1965; Albersheim, 1969) and wood decay (Scheffer and Cowling, 1966; Liese, 1970); in their possible beneficial use in converting waste cellulose into glucose, which may then be converted into the valuable chemical ethanol (Wilkie, 1975); and in their role in cell-wall loosening in higher plants to allow cell elongation and growth (Ridge and Osborne, 1969). The cellulase enzyme system of Trichoderma reesei QM9414 was chosen for this study for two reasons. First, Trichoderma is famous for its ability to degrade highly crystalline cellulose and is one of the most efficient of the cellulolytic fungi (Mandels, 1975). Second, because Trichoderma is such a good source of cellulase, its enzyme system has been studied more extensively than that of any other cellulolytic organism. Consequently, the biochemical characterizations and activities of the various Trichoderma cellulase enzymes are well known.
01 Jun 1982
TL;DR: The highest consumption with respect to total sugar (87%) and the best dry cell yield (15.6 g/l) were observed with the culture of Trichosporon cutaneum using the sugar solution obtained from the hemicellulose component.
Abstract: The components of rice straw, pretreated with sodium chlorite, cellulose and hemicellulose were solubilized with culture filtrate of Pellicularia filamentosa or Trichoderma reesei. The ratio of glucose to total sugar in the solution obtained from the cellulose component with the culture filtrate of Pellicularia filamentosa was approximately twice that of Trichoderma reesei. Ten yeast strains (Candida utilis, C. tropicalis, C. guilliermondii, C. parapsilosis, Torulopsis xylinus, Trichosporon cutaneum, Debaryomyces hansenii, Rhodotorula glutinis, Saccharomyces fragilis and Saccharomyces cerevisiae) were cultivated as test organisms for single-cell protein (SCP) production on sugar solutions obtained from the straw, cellulose and hemicellulose components, pretreated with the culture filtrate of Pellicularia filamentosa. Sugar consumption, in terms of total sugar and cell yield, of the culture with the sugar solution obtained from pretreated straw were; 70% and 6.8 g/l for Candida tropicalis, 56% and 6.4 g/l for Torulopsis xylinus, 76% and 10.1 g/l for Trichosporon cutaneum, and 74% and 7.6 g/l for Candida guilliermondii. In addition, the highest consumption with respect to total sugar (87%) and the best dry cell yield (15.6 g/l) were observed with the culture of Trichosporon cutaneum using the sugar solution obtained from the hemicellulose component.
TL;DR: In this paper, the results of an analytical isoelectric focusing in polyacrylamide gel cylinders and in flat bed gels were analyzed for trichoderma reesei QM 9414 and high-cellulase producing mutants.
Patent•
19 May 1982
TL;DR: In this article, a two-stage process in which cellobiose is produced from a cellulosic feedstock under the influence of Trichoderma reesei in a first stage and converted to glucose in a second stage by the action of purified cellobiase derived from Aspergillus terreus is described.
Abstract: Cellulose is converted to glucose in a two stage process in which cellobiose is produced from a cellulosic feedstock under the influence of Trichoderma reesei in a first stage and cellobiose from the first stage is converted to glucose in a second stage by the action of purified cellobiase derived from Aspergillus terreus. Cellobiase from A. terreus is purified by contacting a crude aqueous extract of the cellobiase with an ion exchange resin and an anion exchange resin. The purified cellobiase may be immobilized on a suitable substrate.
01 Jan 1982
TL;DR: Continuous culture of Natick's strain MCG80 of Trichoderma reesei at a dilution rate of 0.028 h/sup -1/ has yielded a cellulase titer of over 61 U/mL using 5% lactose as the sole carbon source.
Abstract: Continuous culture of Natick's strain MCG80 of Trichoderma reesei at a dilution rate of 0.028 h/sup -1/ has yielded a cellulase titer of over 61 U/mL using 5% lactose as the sole carbon source. Enzyme productivity at this dilution rate is 168 IU/L/h. Repeated fed-batch cultures using this strain on lactose as the carbon source have titers of 10 IU/mL with productivities in excess of 100 IU/L/h. 5 figures, 1 table.
01 Sep 1982
TL;DR: In Trichoderma reesei, QM 9414, β-glucosidase can be selectively induced by xylan suggesting that the synthesis of this enzyme in this organism is under an independent regulatory control.
Abstract: In Trichoderma reesei, QM 9414, β-glucosidase can be selectively induced by xylan. At a concentration of 0.5% xylan in the growth medium, the yield of β-glucosidase is 3 times more than in cellulose medium suggesting that the synthesis of this enzyme in this organism is under an independent regulatory control.
Journal Article•
01 Jan 1982
TL;DR: Trichoderma reesei is a fungus best known for production of an effectiveextracellular cellulase, which normally comprises up to 90% of the extracellular proteins; minor protein components include several carbohydrases and proteases.
Abstract: Trichoderma reesei is a fungus best known for production of an effective extracellular cellulase. When grown on cellulose, the cellulase enzyme complex normally comprises up to 90% of the extracellular proteins; minor protein components include several carbohydrases and proteases. There are several reasons for study of the Trichoderma proteases: a) proteases may be involved with the control of release of extracellular enzymes, e.g., cellulase; b) protease may have important effects on the stability and activity of the cellulase components; and c) proteases may play a role in the production of multiple forms of cellulase components.
TL;DR: Evidence is presented which supports the view that two routes exist for the formation of glucose when cellulosic material is saccharified using T. reesei enzyme preparations, and glucose appears to be formed by a route not involving cellobiose.
Abstract: Evidence is presented which supports the view that two routes exist for the formation of glucose when cellulosic material is saccharified using T. reesei enzyme preparations. The first is via cellobiose and for the second, glucose appears to be formed by a route not involving cellobiose. The second route becomes more apparent when dealing with less crystalline cellulose. This should be considered when constructing strains to produce enzyme preparations for saccharification of less crystalline cellulose.
TL;DR: Measurement of enzyme activities in the various fractions of the mycelium revealed that endoglucanase was truly extracellular while β-glucosidase was cell wall bound.
Abstract: A significant increase in the extracellular yield of β-glucosidase was observed when Trichoderma reesei QM 9414 was cultivated on a cellulose medium containing chitin. Measurement of enzyme activities in the various fractions of the mycelium revealed that endoglucanase was truly extracellular while β-glucosidase was cell wall bound. Treatment of Trichoderma mycelium with cell wall degrading enzymes (produced from Trichoderma) led to a release of β-glucosidase from the mycelium. Apparently chitin, in the presence of cellulose, induces the synthesis of chitinase and other cell wall lytic enzymes which promote release of the intramural β-glucosidase into the medium.
TL;DR: The empirical rate expression previously proposed for the hydrolysis of avicel and tissue paper by Meicelase from Trichoderma viride also held for the production of dewaxing cotton, Solka Floc SW-40 and 1% NaOH-pretreated sawdust.
Abstract: The empirical rate expression previously proposed for the hydrolysis of avicel and tissue paper by Meicelase from Trichoderma viride also held for the hydrolysis of dewaxing cotton, Whatmann CF-11, Solka Floc SW-40, tissue paper and 1% NaOH-pretreated sawdust by Meicelase, Trichoderma reesei QM9414 or Cellulosin from Aspergillus nigar.
TL;DR: A method for determing cell growth in insoluble complex cellulosic fermentations based on material balance relationships is described, using trichoderma reesei QM 9414 growing on leached beet cosette as the experimental system.
Abstract: A method for determing cell growth in insoluble complex cellulosic fermentations based on material balance relationships is described. Trichoderma reesei QM 9414 growing on leached beet cosette is the experimental system used for testing the procedure.
TL;DR: The pattern of release of extracellular cellulase during the germination of Trichoderma reesei spores has been examined and a possible mechanism of spore germination and induction of the enzymes by insoluble cellulose is suggested.
Abstract: The pattern of release of extracellular cellulase during the germination ofTrichoderma reesei spores has been examined. The four enzymes namely, filter paper degrading enzyme, Β-1,4 endoglucanase, Β-glucosidase and xylanase appear sequentially in the culture broth during germination of the spores. The order of enzyme appearance is not altered by the type of carbon source in the germination medium. Measureable quantities of filter paper degrading enzyme is detected only after the outgrowth has occurred. A possible mechanism of spore germination and induction of the enzymes by insoluble cellulose is suggested.
01 Jan 1982
TL;DR: Long time hydrolyses of crystalline cellulose under shaking conditions are markedly improved by the presence of surfactant, the improvement resulting from protection of the CBH against inactivation.
Abstract: Cellulases can be added to the list of enzymes that are inactivated by shaking, agitation, or shearing. Of the cellulases, the most susceptible component is cellobiohydrolase (CBH). A survey of compounds that protect CBH against shaking reveals that some non-ionic surfactants are most potent, being active in the range of one molecule per molecule of enzyme. Under shaking conditions (50°, 350 rpm) where the CBH half-life is 1.5 hours, the presence of Zonyl·FSN increased the half-life to 180 hours. The addition of surfactant to enzyme already inactivated by shaking does not lead to recovery of activity. The presence of surfactant does not improve heat stability of the enzyme under unshaken conditions; nor does it affect the initial rate of hydrolysis. Long time (3 day) hydrolyses of crystalline cellulose under shaking conditions are markedly improved by the presence of surfactant, the improvement resulting from protection of the CBH against inactivation.
Journal Article•
TL;DR: The fermentation of leached beet pulp by the cellulolytic fungus Trichoderma reesei QM 9414 was studied under carbon limitation, with celluloses as the only carbon and energy source.
Abstract: Leached beet pulp is a plentiful waste in the sugar beet industry in Chile, reaching 100.000 metric tons per year on a dry basis. It represents an interesting substrate for protein upgrading through fermentation by cellulolytic organisms, because of the high content of cellulose and hemicellulose, with small amounts of protein and lignin (Table 1). The fermentation of leached beet pulp by the cellulolytic fungus Trichoderma reesei QM 9414 was studied under carbon limitation, with the celluloses as the only carbon and energy source. Nitrogen was supplied as ammonium sulphate and the medium was supplemented with other mineral salts as required for growth. Results on the kinetics of cellulose and hemicellulose degradation, level of reducing sugars in the medium, mycelial growth and production of cellulolytic enzymes are presented. Mycelial growth and related parameters were evaluated by an indirect method, based on nitrogen balances during fermentation. A yield of 0.26 g. of dry cell/g. of cellulosic substrate consumed and productivity of 0.095 g. of dry cell per liter per hour were obtained and compared with reported results on similar systems. After 40 to 45 hours of fermentation, approximately 80% of the cellulose and 45% of the hemicellulose were degraded (Fig. 2). Both, exoglucanase and endoglucanase, were induced; endoglucanase was growth associated, while exoglucanase appeared later in the growth phase, reaching its maximum activity in the stationary phase (Fig. 3). The product obtained was 30% protein and only 40 to 45% residual fiber, mostly hemicellulose. Mild acid hydrolysis has been successful in degrading hemicellulose but not cellulose, in the leached beet pulp.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: Different concentrations of tetramethylthiuram disulfide, sodium dimethyldithiocarbamate, and NaDDC affected the amount of cellulase(s) activity in the culture of Trichoderma reesei, with the greatest increase in Avicelase, CMCase, and β‐glucosidase over the control.
Abstract: Different concentrations of tetramethylthiuram disulfide (TMTD), sodium dimethyldithiocarbamate (NaDDC), and zinc dimethyldithiocarbamate (ZnDDC) affected the amount of cellulase(s) activity in the culture of Trichoderma reesei. After eight days incubation at 28 degrees C the greatest increase in Avicelase, CMCase, and beta-glucosidase over the control were observed at 0.1 ppm (TMTD) and 0.4 ppm (NaDDC and ZnDCC). There was decrease in the growth in the ZnDDC, but beta-glucosidase activity was reduced considerably. Total protein in the culture filtrate increased with the increase in cellulase(s) activity. No change in pH was observed at eight days incubation but pH increased (not exceeding 5.9) at 12 days incubation.
TL;DR: The production of beta-glucosidase from Aspergillus phoenicis in continuous culture is discussed, which can be achieved through supplementation of this enzyme from a separate fermentation.
Abstract: Although the cellulase system of Trichoderma reesei contains all the enzymes necessary for complete hydrolysis of cellulose, the levels of cellobiase (beta-glucosidase) are suboptimal for saccharification purposes. Increasing the level of cellobiase enhances the rate of saccharification of cellulose by reducing the level of cellobiose, an inhibitor of the cellulase system. Even then, cellulase requirements are high, so fermentation studies with T. reesei have concentrated in optimization of cellulase productivity and it is probable that large increments in cellobiase levels can not be attained for this organism without sacrificing cellulase productivity. Optimization of the beta-glucosidase level can be achieved through supplementation of this enzyme from a separate fermentation. This communication discusses the production of beta-glucosidase from Aspergillus phoenicis in continuous culture. (Refs. 11).
Patent•
21 Jul 1982
TL;DR: In this article, the authors proposed a method to produce a cellulase useful as an enzyme source for the production of sugar syrup by the hydrolysis of cellulose, at a low cost, by culturing a specific microbial strain belonging to Trichoderma genus, Thielavia genus or Sporotrichum genus in a medium containing L-sorbose.
Abstract: PURPOSE: To produce a cellulase useful as an enzyme source for the production of sugar syrup by the hydrolysis of cellulose, at a low cost, by culturing a specific microbial strain belonging to Trichoderma genus, Thielavia genus or Sporotrichum genus in a medium containing L-sorbose. CONSTITUTION: A microbial strain capable of producing cellulase from L-sorbose and belonging to Trichoderma genus (e.g. Trichoderma reesei QM 9414), Thielavia genus (e.g. Thielavia terrestris NRRL 8126) or Sporotrichum genus (e.g. Sporotrichum cellulophilum ATCC 20494), is cultured in a medium containing L-sorbose, preferably at 25W50°C and 2.5W7.0pH for 4W10 days under aeration. The cellulase produced and accumulated in the cultured product is separated therefrom. COPYRIGHT: (C)1986,JPO&Japio
Journal Article•
TL;DR: It was shown that selective elimination of acid proteinase from the cellulase preparations by affinity chromatography did not affect the time course of the thermal inactivation of the cellulolytic enzymes under study.
Abstract: The thermal inactivation of the individual cellulolytic components (endoglucanase, EC 3.2.1.4; exoglucosidase, EC 3.2.1.74; cellobiase, EC 3.2.1.21) from the fungi Trichoderma reesei, T. viride, T. lignorum an Aspergillus foetidus has been studied without resolution of the cellulase complexes. The kinetics of the thermal inactivation follow the first order for cellobiase of Asp. foetidus alone and show a more complex picture which is typical for a number of isoenzymes of different thermal stabilities for other cellulolytic components of all the cellulases under study. It was shown that selective elimination of acid proteinase from the cellulase preparations by affinity chromatography did not affect the time course of the thermal inactivation. Covalent attachment of the cellulases to porous glass and to some soluble high polymer supports only resulted in slight stabilizing effects (200-250%). Some polymer effectors (e. g. polyethylene glycols with Mr of 4000 and 40,000 and maltodextrins), as well as the end products of enzymatic hydrolysis of cellulose (i. e. glucose) did not affect the thermal stability of the cellulases under study. In some cases cellulose itself (cotton, CM-cellulose) produced a thermostabilizing effect (3-4-fold) on cellulolytic enzymes.