Showing papers on "Trichoderma reesei published in 1980"
184 citations
TL;DR: Attempts have been made to stabilize the enzymes by chemical modification in such a way as to maintain their solubility, but there was, unfortunately, no increase in enzyme stability, and the activity of enzymes on solid celluloses was adversely affected.
Abstract: Enzyme stability studies have been reinvestigated under the conditions used for cellulose hydrolysis (pH 48, 50 degrees C, 24 hr) The cellobiohydrolase (CBH) component as measured on Avicel is less stable than other enzymes of the cellulase complex, and is 60% inactivated by merthiolate (and other Hg compounds) under the above conditions Endo-beta-1,4-glucanase is much more stable, and more resistant to merthiolate and other compounds Under unshaken conditions the Avicelase of the Rutgers strain C 30 shows greater stability to heat than that of other available strains Biocides must be selected not only for their ability to prevent contamination, but also for their compatibility with cellulases Tetracycline and chlortetracycline are inexpensive, effective in very low concentrations, have no harmful effect on the enzymes, and are compatible with the yeasts that subsequently grow on the sugar solutions to produce alcohol Attempts have been made to stabilize the enzymes by chemical modification in such a way as to maintain their solubility Glutaraldehyde treatment greatly increased the enzyme size, lowered the pI values, and gave a slight shift in the pH activity curve There was, unfortunately, no increase in enzyme stability, and the activity of enzymes on solid celluloses was adversely affected Shaking greatly reduced the hydrolysis of Avicel by Trichoderma reesei C 30 enzyme The adverse effect was accompanied by a decrease in recoverable enzyme and protein
128 citations
TL;DR: This work has identified every site of glycosylation of CBHI from a high cellulase-producing mutant strain of T. reesei, ALKO2877, and characterised each site in terms of its modifying carbohydrate and site-specific heterogeneity.
102 citations
TL;DR: Inactivation of the cellulase of Trichoderma reesei by shear, is of sufficient magnitude to merit consideration in the design of equipment for the enzymatic hydrolysis of cellulose, and the inac inactivation constant is a function of the flow rate of the enzyme solution through a fine capillary tube.
99 citations
TL;DR: A new intracellular beta-glucosidase was isolated from Trichoderma reesei and possible functions may be regulation of cellulase induction and/or to serve as a proenzyme.
Abstract: A new intracellular beta-glucosidase was isolated from Trichoderma reesei. It was sequentially purified by (NH4)2SO4 precipitation and chromatography and rechromatography on Sephadex G-150. The enzyme has a mol.wt. of 98 000, optimal activity at pH 6.5, pI 4.4 and Km values of 6.7 mM and 3.3 mM for sophorose and cellobiose respectively. Possible functions of the enzyme may be regulation of cellulase induction and/or to serve as a proenzyme.
75 citations
TL;DR: Sophorose has two regulatory roles in the production of cellulase enzymes in Trichoderma reesei: beta-glucosidase repression and cellulase induction.
Abstract: Sophorose has two regulatory roles in the production of cellulase enzymes in Trichoderma reesei: beta-glucosidase repression and cellulase induction. Sophorose also is hydrolyzed by the mycelial-associated beta-glucosidase. Repression of beta-glucosidase reduces sophorose hydrolysis and thus may increase cellulase induction.
71 citations
49 citations
TL;DR: The kinetics of the hydrolyses of the cellotriose and of cellotetraose by cellobiohydrolase were studied using a convenient integral technique and reaction mechanisms and mathematical models were postulated to describe the reactions.
Abstract: The kinetics of the hydrolyses of cellotriose and of cellotetraose by cellobiohydrolase were studied using a convenient integral technique. Reaction mechanisms and mathematical models were postulated to describe the reactions. The end-products of the reaction were found to be inhibitory toward hydrolysis in a competitive mode. Hydrolysis of cellotraose produces cellobiose and hydrolysis of cellotriose produces cellobiose and glucose. Both sugars inhibit the enzyme with cellobiose being a stronger inhibitor.
41 citations
TL;DR: It is shown that the difference in inhibition pattern of the two enzymes could be used for determining the contamination of one enzyme by small quantities of the other.
Abstract: Glucanohydrolase from Trichoderma reesei, having a molecular weight of 52,000, was evaluated for kinetic properties with respect to cellobiose Results from this work include: (1) initial rate studies that show that glucanohydrolase hydrolyzes cellobiose by a competitive mechanism and that the product, glucose, inhibits the enzyme; (2) low-pressure aqueous liquid chromatography that shows that formation of a reversion product, cellobiose, is minor and occurs in detectable amounts only a very high (90mM) cellobiose concentrations; (3) development of an equation based on the mechanism of glucanohydrolase action as determined by initial rate kinetics, which accurately predicts the time course of cellobiose hydrolysis; (4) derivation of an initial rate expression for the combined activity of cellobiase and glucanohydrolase on cellobiose Based on data in this paper it is shown that the difference in inhibition pattern of the two enzymes could be used for determining the contamination of one enzyme by small quantities of the other
38 citations
TL;DR: The fungus Trichoderma reesei grows on barley and pachyman, secreting increased quantities of exo-beta 1,3-glucanase, which is found in commercial cellulase preparations, from which it has been partially purified.
Abstract: The fungus Trichoderma reesei grows on barley (Hordeum valgare L.) beta-glucan and pachyman, secreting increased quantities of exo-beta 1,3-glucanase. This enzyme is also found in commercial cellulase preparations, from which it has been partially purified. It has a mol.wt. of 700000, an isoelectric point of 4.2, is cold-stable and hydrolyses both beta 1 Leads to 3- and beta 1 Leads to 6-linkages.
34 citations
01 Jan 1980
01 Jan 1980
TL;DR: Application of ion-exchange high-pressure liquid chromatography protein separations affords a rapid and simple method of separating and comparing cellulase components from potential high-yielding cellulase mutants.
Abstract: The cellulases of two new mutants of T reesei, RUT-NG14 and RUT-C30, have been examined with respect to the separation and biochemical characterization of the various components in the cellulase complex The cellulase of both mutants has been shown to contain enhanced proportions of a cellobiohydrolase by quantitative immune precipitation Application of ion-exchange high-pressure liquid chromatography protein separations affords a rapid (30 min) and simple method of separating and comparing cellulase components from potential high-yielding cellulase mutants
TL;DR: Besides accelerating the rate of degradation and conversion of cassava to cells (0.85g cell/g cassava) the yeast boosted the protein content of the growth product to 51% and the yeast supported the growth of yeast.
01 Jan 1980
TL;DR: Both batch culture and two-stage continuous culture systems were employed to study the growth characteristics, cellulase productivity, the specific rates of nutrient assimilation, and metabolic regulation related to the cellulase biosynthesis of Trichoderma reesei.
Abstract: Both batch culture and two-stage continuous culture systems were employed to study the growth characteristics, cellulase productivity, the specific rates of nutrient assimilation, and metabolic regulation related to the cellulase biosynthesis. Four mutant strains of Trichoderma reesei studied were designated as QM 6a, QM 9414, C 30 (7) and MCG 77 (3). These strains were then compared in terms of specific enzyme productivity, the nutrient requirements and economics, the nature of cellulase components, and the stability and utilization efficiency of cellulase.
01 Jan 1980
TL;DR: Stolk et al. as mentioned in this paper identified Eupenicillium javanicum (Beyma) from its taxonomical characteristics and found that the culture liquid of the fungus showed high crystalline cellulose solubilizing and CM-cellulose saccharifying activities comparable to those of Trichoderma reesei AM 9414.
Abstract: A fungus isolated from a soil sample produced potent cellulolytic enzymes in the culture liquid. The fungus was identified as Eupenicillium javanicum (Beyma) Stolk et Scott from its taxonomical characteristics. The culture liquid of the fungus showed high crystalline cellulose solubilizing and CM-cellulose saccharifying activities comparable to those of Trichoderma reesei AM 9414. The productivity of CM-cellulose saccharifying enzyme of E. javanicum was higher than that of T. reesei QM 9414 and others. The optimum initial pH and cellulose concentration in the medium for production of cellulolytic enzymes were 4.5 and 2 to 3 (w/w)%, respectively. The addition of Tween 80 or Triton X-100 to the medium enhanced remarkably the crystalline cellulose solubilizing and CM-cellulose saccharifying activities in the culture liquid, but not beta-glucosidase activity, which was increased by the addition of phenyl ethyl alcohol.
01 Jan 1980
TL;DR: All the isolates were inhibited competitively by glucose, but certain of them were less sensitive than parent and wild-type to inhibition by glucose.
Abstract: A simple technique, using an esculin-ferric salt visualization system, for selective isolation of mutants of Trichoderma reesei was employed. The ..beta..-glucosidase crude enzyme complexes of the 17 mutants isolated from some 66,000 colonies screened were characterized. Type of inhibition (competitive, noncompetitive) by glucose, and kinetic parameters K/sub m/ (mM pNPG), V/sub max/ (units/mg extracellular protein), and K/sub i/ slopes (mM glucose) were determined for the mutants using p-nitrophenyl ..beta..-D-glucoside (pNPG) as substrate. All the isolates were inhibited competitively by glucose, but certain of them were less sensitive than parent and wild-type to inhibition by glucose. 5 figures, 1 table.
TL;DR: Trichoderma reesei was grown in a vertical glass column filled with a mixture of glass beads and cellulose and cellulase and β-glucosidase activities were first detected in the effluent about 50 h after inoculation and were still present in the Effluent collected 300 h later.
Abstract: Trichoderma reesei was grown in a vertical glass column filled with a mixture of glass beads and cellulose A nutrient solution was supplied to the column at a constant flow rate and the effluent solution was collected in a refrigerated fraction collector Cellulase and β-glucosidase activities were first detected in the effluent about 50 h after inoculation and were still present in the effluent collected 300 h later
01 Jan 1980
TL;DR: In this article, the authors investigated a number of methods for the immobilization of Trichoderma reesei cellulase and commercial 3-glucanase preparations and found that they can reduce wort viscosity and improve filtrability.
Abstract: The abundance of cellulose containing waste materials has given rise to intensive research on enzymatic breakdown of β-glucans (1). The high viscosity due to some cereal polysaccharides and certain other biopolymers frequently causes, even at relatively low concentrations, severe problems during brewing and processing of certain food industry wastes. Soluble s-glucanase active preparations have recently become available to decrease wort viscosity and to improve filtrability, in particular when unmalted grain is used (2,3). An immobilized biocatalyst would be of advantage in providing means for economic continuous processing. Few reports on the immobilization of s-glucanases have been published (4-9). We have investigated a number of methods for the immobilization of Trichoderma reesei cellulase and commercial 3-glucanase preparations.
01 Jan 1980
TL;DR: In this paper, the activity of beta-glucosidase from Trichoderma reesei was studied with respect to its inhibition by Et0H and its role in the degradation of cellulose.
Abstract: The activity of beta-glucosidase from Trichoderma reesei was studied with respect to its inhibition by Et0H and its role in the degradation of cellulose. Ethanol and other alcohols increased the rate of hydrolysis of p-nitrophenyl-Beta-D-glucopyranoside by acting as acceptor molecules for the glucosyl cation. The presence of Et0H resulted in the formation of Et-Beta-D-glucopyranoside. Et0H inhibited the activity of the complete cellulase system, but the extent of inhibition was less than for glucose or cellobiose. Addition of Aspergillus niger Beta-glucosidase to a simultaneous saccharification/fermentation resulted in a 20% increase in conversion of cellulose to Et0H, whereas addition to saccharificatin resulted in a 53% increase in conversion.
Journal Article•
01 Jan 1980
TL;DR: The batch hydrolysis of cellulose by Trichoderma reesei cellulase was found to be considerably enhanced by the addition of very small amounts of β-glucosidase derived from Aspergillus niger.
Abstract: The batch hydrolysis of cellulose by Trichoderma reesei cellulase was found to be considerably enhanced by the addition of very small amounts of β-glucosidase derived from Aspergillus niger Addition of larger amounts had no further effect In simultaneous cellulose hydrolysis and alcohol fermentation experiments the addition of β-glucosidase from A niger had no significant effect on alcohol production by the fermenting yeast
01 Oct 1980
TL;DR: In this paper, the authors have isolated a strain of the fungus Thielavia terrestris that possesses a complete cellulase system, and its enzymes were found to have remarkable thermal stability.
Abstract: The successful utilization of cellulosic materials depends on the development of economically feasible processes for the literation of low molecular weight soluble products from the polymers These soluble products, such as hexoses and pentoses, can then be utilized as substrates for the microbial or chemical product of fuels, food, and chemical feedstocks In the enzymatic saccharification of cellulose, one of the major roadblocks to the development of commercially attractive processes has been the instability of the cellulase complex It is desirable, for example, to operate the conversion systems at elevated temperatures, but environments with high thermal energy can significantly shorten enzyme half life The authors have isolated a strain of the fungus Thielavia terrestris that possesses a complete cellulase system, and its enzymes were found to have remarkable thermal stability The author presents a comparison of the activities of the T terrestris enzymes with those of Trichoderma reesei
Dissertation•
01 Aug 1980