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At least 721 records · Page 40Linked to original sources
PubMed1998

[Purification and properties of alkaline cellulase from alkalophilic Bacillus N6-27].

The alkaline cellulase produced by alkalophilic Bacillus sp. N6-27 was purified to electrophoresis homogeneity by (NH4)2SO4 fractionation, Sepharose CL-4B hydrophobic interaction chromatography, Bio-gel P-150 chromatography. The molecular weight and pI determined by SDS-PAGE and by PAGE-IEF were 94,000 and 4.2, respectively. The optimum temperature and pH for the enzymatic catalysis were 55 degrees C and 8.5, respectively. The enzyme activity was stable under 50 degrees C and in the pH range of 6-11. The substrate was carboxymethylcellulose (CMC). The enzyme activity was strongly inhibited by Fe2+, Cu2+ and Hg2+.

Bacillus↗
PubMed2003

Utilization of banana agricultural waste: production of cellulases by soil fungi.

Banana a major cash crop of Maharashtra is cultivated over 46900 hectares generating large amount of agro waste after the harvest. Attempts were made to utilize these agro wastes for production of cellulases. Of the 127 fungi isolated from the soil of banana field, 12 fungi were found to utilize cellulose as source of carbon. Trichoderma lignorum showed appreciable cellulolytic activity. It produced Cl, Cx and beta glucosidase in Carboxymethyl Cellulose Peptone medium as well as on agro waste based medium containing leaves, stem and rhizome powders. T. lignorum (0. 45 U/ml) produced maximum enzymes on leaf based medium.

Agriculture↗
PubMed1991

Use of a triple protease-deficient mutant of Bacillus subtilis as a host for secretion of a B. subtilis cellulase and TEM beta-lactamase.

The mature portion of the TEM beta-lactamase (BLA) gene (bla) derived from pBR322 was fused with the promoter and signal region of Bacillus subtilis cellulase (BSC) gene (bsc), and the productivity was compared with that of the cloned native bsc gene, using a wild-type B. subtilis strain and a strain deficient in three proteases (i.e., extracellular serine protease, extracellular neutral protease, and the major intracellular serine protease) as hosts. The effects of the sen, sacQ, and prtR genes, carried on the same plasmids, were tested as for the productivities of BSC and BLA. The production of BSC was increased 9-fold by using the combination of the triple-protease deficient strain and the sacQ gene, compared with that by using the wild-type strain as a host, and no degradation of BSC was observed in the triple-protease deficient strain. On the other hand, though the production of the BSC-BLA fusion protein increased 2.5-fold in the triple-protease deficient strain, the BLA activity was decreased after the cell reached the stationary phase of growth, possibly due to some proteolysis. These observations show different sensitivity of secretary proteins to cellular proteases, and suggest that BLA is decomposed by remaining minor proteases.

Amino Acid Sequence↗
PubMed2004

Isothermal microcalorimetric study of the pH dependence of the interactions between a cellulase and a beta-blocker.

The influence of the pH on the complexation equilibria between (S)- or (R)-alprenolol and the cellulase Cel7A was investigated by isothermal titration calorimetry. The results obtained agree with those of previous, similar studies of the same equilibria in which the protein was immobilized on silica particles, packed in a chromatographic column. The association constant and the complexation enthalpy and entropy of the (S)-enantiomer increase with increasing pH. For (R)-alprenolol, the binding is endothermic at all pH values. Thus, for both enantiomers in the pH range 5.5-6.8, the binding is an entropically driven process.

Adrenergic beta-Antagonists↗
PubMed1992

The adsorption of a bacterial cellulase and its two isolated domains to crystalline cellulose.

CenA is a bacterial cellulase (beta-1,4-glucanase) comprised of a globular catalytic domain joined to an extended cellulose-binding domain (CBD) by a short linker peptide. The adsorption of CenA and its two isolated domains to crystalline cellulose was analyzed. CenA and CBD.PTCenA' (the CBD plus linker) adsorbed rapidly to cellulose at 30 degrees C, and no net desorption of protein was observed during the following 16.7 h. There was no detectable adsorption of the catalytic domain. Scatchard plots of adsorption data for CenA and for CBD.PTCenA were nonlinear (concave upward). The adsorption of CenA and CBD.PTCenA exceeded 7 and 8 mumol/g cellulose, respectively, but saturation was not attained at the highest total protein concentrations employed. A new model for adsorption was developed to describe the interaction of a large ligand (protein) with a lattice of overlapping potential binding sites (cellobiose residues). A relative equilibrium association constant (Kr) of 40.5 and 45.3 liter.g cellulose-1 was estimated for CenA and CBD.PTCenA, respectively, according to this model. A similar Kr value (33.3 liter.g-1) was also obtained for Cex, a Cellulomonas fimi enzyme which contains a related CBD but which hydrolyzes both beta 1,4-xylosidic and beta-1,4-glucosidic bonds. It was estimated that the CBD occupies approximately 39 cellobiose residues on the cellulose surface.

Adsorption↗
PubMed2005

[Kinetics model of spherical immobilized cellulase].

A kinetics model was developed for predicting and simulating immobilized cellulase performance, which follows Michaelis-Menten kinetics with competitive product inhibition. Taking into account the effects of competitive product inhibition, inner diffusional limitation, substrate concentration and carrier size, the substrate distribution and the product distribution in carriers were investigated, and the effectiveness factors were also calculated over a wide range of parameters. The effects of competitive product inhibition are shown to increase the substrate concentration in the carrier, and, additionally, to increase the effectiveness factors slightly. With the increase of inner diffusion coefficient, both the effectiveness factors and the substrate concentration in the carrier increase. As the carrier size increases, on the other hand, these values decrease. The effectiveness factors and the substrate concentration in the carrier are found to increase when substrate concentration in the reaction system increases.

Cellulase↗
PubMed2005

[Construction and screening of phage display single chain antibody library against Bursaphelenchus xylophilus cellulase].

A phage display single-chain variable fragment (scFv) library against Bursaphelenchus xylophilus cellulase (BXC) was constructed and used to screen the specific antibodies binding to BXC. The total RNA was extracted from fresh spleens of BALB/C mice immunized with BXC. Gene fragments encoding VH and VL were amplified by RT-PCR and assembled into a single chain by overlapping PCR with a linker DNA encoding the peptide (Gly4Ser)3. The recombinant fragments were cloned into the phagemids (pCANTABSE) and electroporated into E. coli TG1. The recombinant phagemids were rescued by reinfection of helper phage M13K07. The repertoire of the phage display antibody was about 5 x 10(4). The specific antibodies against BXC were obtained after five rounds of affinity selection. The positive phage clone was used to infect E. coli HB2151. SDS-PAGE and western blot analysis showed that the soluble scFv antibodies expressed bound specifically to BXC. The studies laid foundation for quarantine and pathological study of Bursaphelenchus xylophilu.

Animals↗
PubMed1991

Characterization of commercial Trichoderma reesei cellulase preparations by denaturing electrophoresis (SDS-PAGE) and immunostaining using monoclonal antibodies.

Fifteen different cellulase preparations from Trichoderma reesei, obtained either commercially or from pilot plants, were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting using monoclonal antibodies against two cellobiohydrolases (CBH I, CBH II), an endoglucanase (EG I), and beta-glucosidase. The staining patterns were compared with the activities of the preparations against filter paper (FPU), carboxymethylcellulose (CMC-ase), cellobiose (beta-glucosidase), and azocasein (protease). Variable amounts of proteolytic degradation products of CBH I, CBH II, and EG I were seen in most samples, and only half of them contained intact beta-glucosidase. The degree of proteolysis did not correlate with any significant difference in the respective activities of these preparations against filter paper cellulose or carboxymethylcellulose. In more than 50% of all cases a decreased beta-glucosidase activity and the absence of intact beta-glucosidase protein in Western blots was observed in preparations displaying high proteolytic activity.

Antibodies, Monoclonal↗
PubMed1991

[The effect of cellulase on calves fed an acidified milk diet].

The purpose of this research was to establish the influence of 3 j Cx cellulase applied per gram of COT concentrate mixture, fed in combination with a milk diet acidified by formic acid to the value of pH 4.6, on calf growth performance in one metabolism and two field experiments. In the metabolism experiment two groups of calves, with six animals in each, were fed acidified whole milk, which was diluted stage by stage till weaning at 60 days of age. The average live weight gain in the control at the end of the milk feeding period, i.e. from 14 to 60 days of age, was 29.90 kg. This corresponds to a daily live weight gain of 0.650 g. The total live weight gain of male calves in the experimental group was 29.30 kg, corresponding to a daily live weight gain of 0.638 g (Tab. I). Tab. II shows the average feed and nutrient intakes per kg live weight gain. The calves which received the enzyme supplement tend to have the higher feed conversion rate. During the forage feeding period, i.e. from 61 to 90 days of age, the average daily live weight gains were 1.10 kg and 0.980 kg in the control and experimental groups, respectively (Tab. III). The average live weight of 90 days old male calves was 107.70 kg and 103.90 kg in the control and experimental groups, respectively. The amount of consumed nutrients (digestible protein and starch units); in relation to the total feed intakes, is lower in the experimental groups, which proves the higher feed conversion rate (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1991

Production of cellulase(s) by Myriococcum albomyces.

The ability of the facultative thermophilic fungi Myriococcum albomyces (Cooney et Emerson) to produce extracellular cellulase(s) in a stationary liquid medium was studied. Diverse cellulosic carbon sources were used, assessing the different cellulolytic activities and enzymes different celluloytic activities and enzymes of the fungus (expressed in the classic terms C1-, Cx-activity) and their temperature and pH optima. The optimum temperature for "C1"-"Cx"-activity was 45 degrees C. The optimum pH for "C1"-activity was pH 6 while that for "Cx"-activity was pH 5.

Ascomycota↗
PubMed1975

Influence of amino acids on the activity of cellulolytic enzymes obtained from spent medium of Fusarium cultures and on the "Cellulase S" Novo.

Comparative studies on the influence of 4 amino acids (cysteine, cystine, methionine and alanine) on the activity of enzymatic preparation were carried out. The action of the amino acids was shown to depend on pH, incubation time and the temperature of incubation. Attempts were made to find a correlation between the amino acids introduced and redox potential (Eh), pH and the activity of the cellulolytic enzymes. It was found that the addition of some amino acids to the reaction mixtures at different pH values affected the value of Eh -- which enhanced the cellulase activity.

Alanine↗
PubMed1989

Structural and functional analysis of a bacterial cellulase by proteolysis.

CenA is an endo-beta 1,4-glucanase from the cellulolytic bacterium Cellulomonas fimi. It is a bifunctional enzyme comprising an amino-terminal cellulose-binding domain and a carboxyl-terminal catalytic domain joined by a short sequence of prolyl and threonyl residues (the Pro-Thr box). Additional structural and functional information was revealed by a detailed analysis of the products generated by proteolytic cleavage of a nonglycosylated form of CenA. An extracellular C. fimi protease attacked nonglycosylated CenA at the junctions between the Pro-Thr box and the two functional domains. A stable "core" peptide (p30), corresponding to the catalytic domain, remained after extensive proteolysis. p30 was resistant to further attack even in the presence of 2-mercaptoethanol plus urea or dithiothreitol, but treatment in the presence of sodium dodecyl sulfate allowed complete fragmentation to small peptides. Stable peptides, identical, or closely related to p30, were generated by alpha-chymotrypsin or papain. These results indicated that the catalytic domain adopts a tightly folded conformation affording protection from proteolytic attack. In contrast, the cellulose-binding domain showed a relatively loose conformation. Progressive proteolytic truncation from the amino terminus was apparent during incubation with alpha-chymotrypsin or papain, or with C. fimi protease under reducing conditions. Affinity for cellulose was retained by products missing up to 64 amino-terminal amino acids. The remaining carboxyl-proximal region of the cellulose-binding domain with affinity (47 amino acids) contained sequences highly conserved in analogous domains from other bacterial endo-beta 1,4-glucanases. By analogy with other systems, the properties of the Pro-Thr box are consistent with an elongated conformation. The results of this investigation suggest that CenA has a tertiary structure which resembles that of certain fungal cellulases.

Amino Acid Sequence↗
PubMed1987

Cellulase slide preparation of methylcellulose cultures of hemopoietic cells.

A technique is described for making slides of colonies grown in methylcellulose semisolid medium. The entire contents of a 0.5-ml culture in a 24-well plate is digested using 0.25 ml of a 1.08-mg/ml solution of cellulase dissolved in fetal calf serum. The methylcellulose is digested overnight, and the well contents are transferred to slides and are stained. Adherent colonies are recovered using a fetal calf serum solution containing trypsin and EDTA to flush any residue from the well; the recovered cells are transferred to slides and then stained. This method produces slides free of the darkly stained methylcellulose background that interferes with viewing colonies and studying individual cells.

Animals↗
PubMed1979

Characterization of a cellulase producing mold, Trichoderma sp. W-10 isolated from infected mushroom spawn.

A potent cellulase producing mold, Tichoderma sp. W-10 suitable for enzyme production with solid state culture was isolated from infected mushroom spawn, its characteristics and taxonomic studies were carried out. As a result, this mold was identified as Trichoderma koningii (Oudemans) according to the keys of Gilman and Rifai's classification system and the morphological features described by Komatsu. Meanwhile, a detail survey of physiological, cultural and biochemical characteristics were also described.

Basidiomycota↗
PubMed1984

Cellulolytic activity of moulds. III. Enzymatic hydrolysis of cellulose by cellulase preparation from Aspergillus terreus F-413.

The strain Aspergillus terreus F-413 was used to obtain cellulolytic enzymes; it was cultivated on cellucotton by the submerged method in a 101 fermenter. The crude enzymatic preparation obtained from the post-culture liquid, containing small amounts of other enzymes besides active cellulases, was used for hydrolysis of several kinds of cellulose. The highest saccharification percentage was obtained with cellucotton and filter paper, while the lowest with lignocellulosic materials such as straw and sawdust. It was shown that cellulose pretreatment, both mechanical (grinding in a ball mill) and chemical (with alkali) distinctly increased the yield of enzymatic hydrolysis. In the obtained hydrolyzates the presence of glucose as the main product of cellulose decomposition was found.

Aspergillus↗
PubMed1984

Cellulolytic activity of moulds. IV. Evaluation of the utility of cellulosic wastes for biosynthesis of cellulases and xylanase by Aspergillus terreus F-413.

The value of various cellulosic wastes for the synthesis of cellulolytic enzymes by the mould Aspergillus terreus F-413 was determined in submerged culture. The best results were obtained by using beet pulp. The dynamics of their synthesis was observed during a 12-day culture on the medium most favourable for the synthesis of cellulases.

Aspergillus↗
PubMed1982

Cellulolytic activity of moulds. I. Characteristics of the cellulases complex and xylanase of the strain Aspergillus terreus F-413.

Among 79 strains of moulds belonging to 17 different species, the strain Aspergillus terreus F-413 which showed the highest cellulolytic activity was isolated for further studies. Some properties of the complex of cellulases formed by this strain as well as the dynamics of their synthesis under optimal submerged culture conditions were characterized.

Aspergillus↗
PubMed1978

[Investigation of Ca2+ inhibitory effect on cellulase activity].

The Ca2+ effect on the activity of cellulase [beta-1-4-endoglucanase) is quantitatively estimated. Values of partial inhibition of the enzyme activity at different Ca2+ concentrations within 2-10 mM are determined. The type of inhibition is identified from the data on kinetic analysis. The values of substrate and inhibitory constants are calculated.

Calcium↗