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PubMed1978

Mutarotation of hydrolysis products by different types of exo-cellulases from Trichoderma viride.

Mutarotation of products from p-nitrophenyl beta-D-cellobioside and cellopentaitol by two different types of exo-cellulases from Trichoderma viride was investigated. It was found that an exo-cellulase of glucosidase type produced from the former substrate D-glucose which was mutarotated in a downward direction, while another exo-cellulase of Avicelase type produced from the latter substrate cellobiose which was mutarotated in an upward direction.

Animals↗
PubMed1967

Massive synthesis of ribonucleic Acid and cellulase in the pea epicotyl in response to indoleacetic Acid, with and without concurrent cell division.

Measurements were made over a 4-day period of the effect of added indoleacetic acid (IAA), puromycin, actinomycin D and 5-fluorodeoxyuridine (FUdR) on growth and the levels of total DNA, RNA, protein and cellulase in segments of tissue at the apex of decapitated etiolated epicotyls of Pisum sativum, L. var. Alaska.The hormone induced swelling of parenchyma cells and cell division. By 3 days after IAA application, the amounts of DNA and protein were approximately double, RNA triple and cellulase 12 to 16 times the levels in controls. All of these changes were prevented by both puromycin and actinomycin D. FUdR prevented DNA synthesis and cell division but not swelling or synthesis of RNA, protein and cellulase.It is concluded that IAA-induced RNA synthesis is required for cellulase synthesis and lateral cell expansion, whether or not cell division takes place.

Journal Article↗
PubMed1978

Cellulase activity and fruit softening in avocado.

Cellulase activity in detached avocado (Persea americana Mill.) fruits was found to be directly correlated with ripening processes such as climacteric rise of respiration, ethylene evolutin, and softening. This activity in the pericarp could be induced by ethylene treatment, and the more mature the fruit-the faster and the greater was the response. Only a very low cellulase activity could be detected in hard avocado fruit right after harvest. Cellulase activity was highest at the distal end of the fruit, lower in the midsection, and lowest at the proximal end. The enzyme is heat-labile and appeared to have activity of an endocellulase nature mainly. Electron micrographs of cell walls from hard and soft fruits are presented.

Journal Article↗
PubMed1979

Polygalacturonase and Cellulase Enzymes in the Normal Rutgers and Mutant rin Tomato Fruits and Their Relationship to the Respiratory Climacteric.

Cell wall enzymes at different stages of fruit development were compared between the normal Rutgers and the isogenic nonripening rin tomato. In Rutgers, a detectable increase in polygalacturonase (PG) activity was observed 6 days prior to the respiratory climacteric (43 days postanthesis). The maximum increase in PG activity occurred after C(2)H(2) and CO(2) production reached their peak. However, in the rin tomato, no change in PG activity was noted up to 100 days postanthesis. Cellulase activity increased in Rutgers fruits prior to the respiratory climacteric and continued to increase thereafter. Similar changes in cellulase activity were also observed in the nonclimacteric rin fruits. Short term ethylene treatment (2 days) of 36-day-old rin fruits increased cellulase activity, but had no effect on PG activity. Detectable changes in other parameters of ripening, such as chlorophyll loss and softening, also occurred prior to the respiratory climacteric. These results suggest that the failure of rin fruits to ripen is related to their low PG activity during maturity as compared with normal fruits.

Journal Article↗
PubMed1990

Anatomical Changes and Immunolocalization of Cellulase during Abscission as Observed on Nitrocellulose Tissue Prints.

A fundamental event in abscission is the breakdown of cell wall material in a discrete zone of cells known as the separation layer. Three dimensional images produced by viewing tissue prints of abscission zones on nitrocellulose (NC) membranes with incident illumination showed changes in the tissue integrity taking place in the separation layer as the process of abscission proceeded. The cell softening which occurs due to the dissolution of the cell wall appeared in the tissue prints as a diffuse line at the anatomical transition between the pulvinus and petiole and was easily observed on NC tissue prints of either longitudinal or serial cross-sections through abscission zones. In bean leaf abscission the dissolution of cell walls has been correlated with the appearance of a form of cellulase with an isoelectric point of pH 9.5. Antibodies specific for this enzyme were used to study the localization of 9.5 cellulase in the distal abscission zone of Phaseolus vulgaris L., cv Red Kidney after tissue printing on NC. It was found that 9.5 cellulase was localized in the separation layer but also occurred in the vascular tissue of the adjacent pulvinus. No antibody binding was observed in nonabscising tissue or preimmune controls. These results confirm previous biochemical studies and demonstrate that immunostaining of nitrocellulose tissue prints is a fast and reliable method to localize proteins or enzymes in plant tissue.

Journal Article↗
PubMed1982

Saccharification of Complex Cellulosic Substrates by the Cellulase System from Clostridium thermocellum.

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 5.7 and 6.1 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.

Journal Article↗
PubMed1984

Effect of 3-Phenylpropanoic Acid on Capsule and Cellulases of Ruminococcus albus 8.

The morphology and cellulases of Ruminococcus albus 8 were markedly affected by the inclusion of 3-phenylpropanoic acid (PPA) in a defined growth medium. PPA-grown bacteria produced substantial quantities of cell-bound cellulase, as well as a very high-molecular-weight extracellular enzyme and lesser amounts of two low-molecular-weight enzymes. PPA-deprived bacteria produced greater total amounts of cellulase, but all of it exists in soluble, low-molecular-weight forms. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the availability of PPA did not affect the kinds of proteins produced, but the distribution of two major proteins between cells and supernatant was PPA dependent. These two proteins (85 and 102 kilodaltons) were primarily associated with the cells of PPA-grown bacteria but were found chiefly in the supernatants of PPA-deprived cultures. Examination of thin sections of PPA-grown R. albus 8 by transmission electron microscopy showed a lobed ruthenium red-staining capsule surrounding the cell wall, as well as small vesicular structures (diameter, 0.05 to 0.06 mum) which appeared to aggregate into larger spherical units (diameter, 0.2 to 0.3 mum). In contrast, thin sections of PPA-deprived cells were devoid of vesicles and showed little or no capsule surrounding the cells.

Journal Article↗
PubMed1987

Sporotrichum thermophile Growth, Cellulose Degradation, and Cellulase Activity.

The activity of components of the extracellular cellulase system of the thermophilic fungus Sporotrichum thermophile showed appreciable differences between strains; beta-glucosidase (EC 3.2.1.21) was the most variable component. Although its endoglucanase (EC 3.2.1.4) and exoglucanase (EC 3.2.1.91) activities were markedly lower, S. thermophile degraded cellulose faster than Trichoderma reesei. The production of beta-glucosidase lagged behind that of endoglucanase and exoglucanase. The latter activities were produced during active growth. When growth was inhibited by cycloheximide treatment, the hydrolysis of cellulose was lower than in the control in spite of the presence of both endoglucanase and exoglucanase activities in the culture medium. Degradation of cellulose was a growth-associated process, with cellulase preparations hydrolyzing cellulose only to a limited extent. The growth rate and cell density of S. thermophile were similar in media containing cellulose or glucose. A distinctive feature of fungal development in media incorporating cellulose or lactose (inducers of cellulase activity) was the rapid differentiation of reproductive units and autolysis of hyphal cells to liberate propagules which were capable of renewing growth immediately.

Journal Article↗
PubMed1988

Escherichia coli Spheroplast-Mediated Transfer of pBR322 Carrying the Cloned Ruminococcus albus Cellulase Gene into Anaerobic Mutant Strain FEM29 by Protoplast Fusion.

Intergeneric protoplast fusion between Escherichia coli HB101 with pBR322 carrying the cloned o-(carboxymethyl)cellulase (CMCase) gene of Ruminococcus albus (Pro Leu Ap Km) and an anaerobic mutant strain, FEM29 (Trp His Ap Km), with dehydrodivanillin-degrading activity was performed in the presence of 40% polyvinyl alcohol 300 under aerobic and anaerobic conditions to transfer the cloned cellulase gene into the mutant. The mutant FEM29 had a unique property. When it was incubated in liquid medium with 1% glucose and sucrose, protoplasts could be produced autogenously and regenerated on the agar slant. E. coli spheroplasts formed from a plasmid-amplified overnight culture after 10 min of treatment with lysozyme (20 mug/ml) in a hypertonic solution (0.01 M Tris hydrochloride [pH 7.5], 0.4 M mannitol). Protoplast regeneration rates of FEM29 and HB101 were 30 and 83%, respectively, on the agar-yeast extract medium. Ap Km fusants were obtained at high frequency: 1.7 x 10 anaerobically and 8.2 x 10 aerobically. These fusants showed 23 to 57% of CMCase and dehydrodivanillin-degrading activities, respectively, as compared with parental strains. All the fusants isolated were gram-negative rods with main phenotypes such as urease and catalase activities as in HB101 and esterase and chymotrypsin activities as in FEM29. Southern hybridization experiments suggested that pBR322 with the cloned CMCase gene existed autonomously in the fusant cells. This is the first report describing transfer of pBR322 with a cloned cellulase gene into an anaerobic mutant by polyvinyl alcohol-mediated fusion with an E. coli spheroplast.

Journal Article↗
PubMed1990

Interrelationship of Xylanase Induction and Cellulase Induction of Trichoderma longibrachiatum.

Xylose oligomers rapidly induced xylanase activity of Trichoderma longibrachiatum, whereas induction was delayed in the presence of glucose. Cellobiose, cellopentaose, and xylobiose did not induce detectable levels of cellulase activity. However, mixtures of xylobiose with cellobiose or cellopentaose rapidly induced cellulase activity. In addition, mixtures of xylobiose with cellopentaose or cellobiose induced xylanase activity more effectively than xylobiose alone. Both xylanase and cellulase activity were detected after a lag period in the presence of lactose.

Journal Article↗
PubMed1971

Cellulase production by Thermomonospora curvata isolated from municipal solid waste compost.

A cellulolytic, thermophilic actinomycete (previously isolated from municipal refuse compost samples) was identified as Thermomonospora curvata. A determination was made of the optimal conditions for cellulase production by T. curvata when grown at 55 C in a medium containing mineral salts, cellulose, and yeast extract. The pH and temperature optima (pH 6.0 and 65 C) for the cellulase produced by T. curvata were identical to those previously observed for the cellulase extracted from crude compost samples. Such similarities, together with the prevalence of T. curvata in compost samples and its ability to grow at composting temperatures, indicate that this actinomycete could possibly be considered as a major cellulose decomposer in the municipal refuse composting process.

Actinomycetales↗
PubMed1972

Cellulolytic activity of Thermomonospora curvata: optimal assay conditions, partial purification, and product of the cellulase.

Thermomonospora curvata produces cellulases active against both cotton fibers (designated C(1) activity) and carboxymethylcellulose (C(x) activity). In reaction systems employing optimal substrate concentration, pH, and temperature, hydrolysis rates (measured by the release of soluble reducing sugars) were initially linear and decreased on prolonged incubation, although only a small amount of substrate (1 to 2%) had been hydrolyzed. Persistence of this lower rate, even after addition of fresh enzyme (in the C(1) assay system), indicated alteration of cellulose susceptibility to hydrolysis rather than enzyme inactivation. Partial purification by (NH(4))(2)SO(4) precipitation and exclusion chromatography resolved cellulase activity into two fractions. The sole product of purified cellulase activity on ground cotton fibers appears to be cellobiose.

Actinomycetales↗
PubMed1999

Mathematical modeling and optimization of cellulase protein production using Trichoderma reesei RL-P37.

The enzyme cellulase, a multienzyme complex made up of several proteins, catalyzes the conversion of cellulose to glucose in an enzymatic hydrolysis-based biomass-to-ethanol process. Production of cellulase enzyme proteins in large quantities using the fungus Trichoderma reesei requires understanding the dynamics of growth and enzyme production. The method of neural network parameter function modeling, which combines the approximation capabilities of neural networks with fundamental process knowledge, is utilized to develop a mathematical model of this dynamic system. In addition, kinetic models are also developed. Laboratory data from bench-scale fermentations involving growth and protein production by T. reesei on lactose and xylose are used to estimate the parameters in these models. The relative performances of the various models and the results of optimizing these models on two different performance measures are presented. An approximately 33% lower root-mean-squared error (RMSE) in protein predictions and about 40% lower total RMSE is obtained with the neural network-based model as opposed to kinetic models. Using the neural network-based model, the RMSE in predicting optimal conditions for two performance indices, is about 67% and 40% lower, respectively, when compared with the kinetic models. Thus, both model predictions and optimization results from the neural network-based model are found to be closer to the experimental data than the kinetic models developed in this work. It is shown that the neural network parameter function modeling method can be useful as a "macromodeling" technique to rapidly develop dynamic models of a process.

Cellulase↗
PubMed2000

Effect of substrate and cellulase concentration on simultaneous saccharification and fermentation of steam-pretreated softwood for ethanol production.

Economic optimization of the production of ethanol by simultaneous saccharification and fermentation (SSF) requires knowledge about the influence of substrate and enzyme concentration on yield and productivity. Although SSF has been investigated extensively, the optimal conditions for SSF of softwoods have yet not been determined. In this study, SO2-impregnated and steam-pretreated spruce was used as substrate for the production of ethanol by SSF. Commercial enzymes were used in combination with the yeast Saccharomyces cerevisiae. The effects of the concentration of substrate (2% to 10% w/w) and of cellulases (5 to 32 FPU/g cellulose) were investigated. SSF was found to be sensitive to contamination because lactic acid was produced. The ethanol yield increased with increasing cellulase loading. The highest ethanol yield, 68% of the theoretical based on the glucose and mannose present in the original wood, was obtained at 5% substrate concentration. This yield corresponds to 82% of the theoretical based on the cellulose and soluble glucose and mannose present at the start of SSF. A higher substrate concentration caused inefficient fermentation, whereas a lower substrate concentration, 2%, resulted in increased formation of lactic acid, which lowered the yield. Compared with separate hydrolysis and fermentation, SSF gave a higher yield and doubled the productivity.

Carbohydrate Metabolism↗
PubMed2006

A complete protein pattern of cellulase and hemicellulase genes in the filamentous fungus Trichoderma reesei.

The complete protein pattern of cellulase and hemicellulase genes was studied through the Genome-wide analysis in Trichoderma reesei. The genome database revealed the presence of 39 ORFs encoding related proteins, including 32 enzymes with a catalysis domain related to cellulases and hemicellulases and 7 related proteins with a cellulose-binding module (CBM). Ten of these encoded yet undescribed enzymes, including six novel beta-glucosidases or xylosidases, two putative xylanases and two undescribed mannases. To better illustrate the relation of these 39 related proteins, four groups were created and analyzed by phylogenetic analysis: group A corresponding to xylanases, group B belonging to mannases and acting to degrade mannan; group C containing all known and putative cellulose-degrading proteins that have highly conserved CBMs; and group D containing beta-glucosidase and beta-xylosidase. Group D was the largest group, in which 8 beta-glucosidases appeared to be non-secreted proteins.

Cellulase↗
PubMed2006

Standard assays do not predict the efficiency of commercial cellulase preparations towards plant materials.

Commercial cellulase preparations are potentially effective for processing biomass feedstocks in order to obtain bioethanol. In plant cell walls, cellulose fibrils occur in close association with xylans (monocotyls) or xyloglucans (dicotyls). The enzymatic conversion of cellulose/xylans is a complex process involving the concerted action of exo/endocellulases and cellobiases yielding glucose and xylanases yielding xylooligomers and xylose. An overview of commonly measured cellulase-, cellobiase-, and xylanase-activity, using respectively filter paper, cellobiose, and AZCL-dyed xylan as a substrate of 14 commercially available enzyme preparations from several suppliers is presented. In addition to these standardized tests, the enzyme-efficiency of degrading native substrates was studied. Grass and wheat bran were fractionated into a water unsoluble fraction (WUS), which was free of oligosaccharides and starch. Additionally, cellulose- and xylan-rich fractions were prepared by alkaline extraction of the WUS and were enzymatically digested. Hereby, the capability of cellulose and xylan conversion of the commercial enzyme preparations tested was measured. The results obtained showed that there was a large difference in the performance of the fourteen enzyme samples. Comparing all results, it was concluded that the choice of an enzyme preparation is more dependent on the characteristics of the substrate rather than on standard enzyme-activities measured.

Biological Assay↗
PubMed2007

Design of highly efficient cellulase mixtures for enzymatic hydrolysis of cellulose.

An extremely highly active cellobiohydrolase (CBH IIb or Cel6B) was isolated from Chrysosporium lucknowense UV18-25 culture filtrate. The CBH IIb demonstrated the highest ability for a deep degradation of crystalline cellulose amongst a few cellobiohydrolases tested, including C. lucknowense CBH Ia, Ib, IIa, and Trichoderma reesei CBH I and II. Using purified C. lucknowense enzymes (CBH Ia, Ib, and IIb; endoglucanases II and V; beta-glucosidase, xylanase II), artificial multienzyme mixtures were reconstituted, displaying an extremely high performance in a conversion of different cellulosic substrates (Avicel, cotton, pretreated Douglas fir wood) to glucose. These mixtures were much or notably more effective in hydrolysis of the cellulosic substrates than the crude multienzyme C. lucknowense preparation and other crude cellulase samples produced by T. reesei and Penicillium verruculosum. Highly active cellulases are a key factor in bioconversion of plant lignocellulosic biomass to ethanol as an alternative to fossil fuels.

Cellulase↗
PubMed1977

Growth kinetics and cellulase biosynthesis in the continuous culture of Trichoderma viride.

Continuous culture studies have been carried out growing Trichoderma viride QM 9123 in a 10 liter stirred fermentor on a medium containing commercial glucose as the carbon source. Experiments were carried out at 30 degrees C and at three controlled pH values of 2.5, 3.0, and 4.0 over a range of dilution rates from 0.01 to 0.11 hr-1. Steady-state values of cell, glucose, and cellulase concentration oxygen tension, and outlet gas oxygen partial pressure were recorded. Values of maximum specific growth rate, endogenous metabolism coefficient, Michaelis-Menten coefficient, yield and maintenance coefficient for glucose were derived and correlated the effect of the hydrogen ion concentration. Specific oxygen uptake rates were correlated with specific growth rates and absorption coefficients were shown to be a function of dilution rate independent of pH. Some data on cellulase biosynthesis were examined and correlated in terms of a maturation time model.

Cellulase↗