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Journal ArticleDOI

Expression of xylanase and cellulase enzymes in a newly isolated Clostridium sp.SAIV

01 May 1991-Enzyme and Microbial Technology (Elsevier)-Vol. 13, Iss: 5, pp 430-435
TL;DR: Clostridium sp.
About: This article is published in Enzyme and Microbial Technology.The article was published on 1991-05-01. It has received 12 citations till now. The article focuses on the topics: Cellulase & Xylanase.
Citations
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Journal ArticleDOI
TL;DR: This is the first report on the production, characterization of a xylanase from genus Kluyvera and its application for butanol production directly from hemicelluloses.

73 citations

Journal ArticleDOI
TL;DR: The enzyme induction was repressed by high concentration of glucose and this could not be reversed by exogenous cyclic-adenosine 3′,5′-monophosphate (cAMP).

51 citations

01 Jul 2013
TL;DR: A culture independent 16S rDNA approach was taken up for more detailed analysis of cow dung microbiota, finding culturable bacteria constituted 83.3% in the phylum Bacteroidetes and 87.5% in Firmicutes.
Abstract: Cow dung is being used from ancient times in agriculture as it has a significant role in plant growth promotion and plant protection. It is also being used in various religious practices as a purifier. Since only a small fraction of the total microbial diversity can be recovered by culturable methods, a culture independent 16S rDNA approach was taken up for more detailed analysis of cow dung microbiota. Total community DNA was extracted from fresh dung of Brown-Swiss breed and bacterial 16S rRNA genes were subsequently amplified, cloned, sequenced and deposited in GenBank. Bacteria belonging to the phyla Bacteroidetes (38.3%), Firmicutes (29.8%), Proteobacteria (21.3%) and Verrucomicrobia (2%) were identified. Bacteroidetes clones included the genera Bacteroides, Alistipes and Paludibacter; while Clostridium, Ruminococcus, Anaerovorax and Bacillus were predominant in Firmicutes. αand γ-proteobacterial genera included Acinetobacter, Pseudomonas, Rheinheimera, Stenotrophomonas and Rhodobacter. The Verrucomicrobial clone showed high similarity to Akkermansia. Unculturable bacteria constituted 83.3% in the phylum Bacteroidetes and 87.5% in Firmicutes. All clones under phylum Proteobacteria were culturable bacteria. Eight per cent of the clone library represented previously uncharacterized and unidentified bacteria.

50 citations

Journal ArticleDOI
TL;DR: This is the first report of a Clostridium strain growing at 20 degrees C and producing an array of xylanolytic and cellulolytic enzymes, possessing low temperature optima of 20 degreesC, which may facilitate degradation of plant fibre under low-temperature conditions.
Abstract: A Clostridium strain PXYL1 was isolated from a cold-adapted cattle manure biogas digester at 15°C. It could grow at temperatures as low as 5°C up to 50°C with highest specific growth rate at 20°C and is a psychrotroph. It produced extracellular hydrolytic enzymes namely xylanase, endoglucanase, β-xylosidase, β-glucosidase and filter paper cellulase, all of which had maximal activity at 20°C. The induction of xylanase was highest on birch wood xylan (37 IU(mg protein)−1) compared with xylose (1.11 IU(mg protein)−1), cellobiose (1.43 IU(mg protein)−1) and glucose (no activity). The xylanase was thermolabile with a half-life of 30 min at 40°C and 8 min at 50°C but stable for over 2 h at 20°C. The crude enzyme released reducing sugars (1.25 g l−1) from finger millet flour at 20°C, while commercial food-grade xylanases showed no hydrolysis at this temperature. This is the first report of a Clostridium strain growing at 20°C and producing an array of xylanolytic and cellulolytic enzymes, possessing low temperature optima of 20°C, which may facilitate degradation of plant fibre under low-temperature conditions.

48 citations

Journal ArticleDOI
TL;DR: Extracellular endo-1,4-β-xylanase (EC 3.2.1.8) synthesis in the yeast Trichosporon cutaneum SL409 is inducible and can be induced in washed glucose-grown cells by xylan or xylose.

44 citations

References
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Journal Article
TL;DR: Procedures are described for measuring protein in solution or after precipitation with acids or other agents, and for the determination of as little as 0.2 gamma of protein.

289,852 citations

Journal ArticleDOI
09 Sep 1950-Nature
TL;DR: Modifications are introduced, based on a test given by Feigl for reducing sugars, which eliminate the heating step, and in which the reagents are applied in organic solvents, thus removing the danger of migration of the sugar spots.
Abstract: THE ammoniacal silver nitrate spray1 used for the detection of sugars has several disadvantages; to those mentioned by Partridge2 should be added the necessity for very careful control of the heating step, particularly important in laboratories lacking special apparatus. We have introduced modifications, based on a test given by Feigl3 for reducing sugars, which eliminate the heating step, and in which the reagents are applied in organic solvents, thus removing the danger of migration of the sugar spots. The method has been in use for more than a year, and has proved easy to handle and extremely reliable.

3,526 citations

Journal ArticleDOI
TL;DR: Strains of Trichoderma, particularly T. reesei and its mutants, are good sources of extracellular cellulase suitable for practical saccharification and carbon compounds derived from enzymatic hydrolysis of cellulose will be used as fermentation and chemical feedstocks as soon as the process economics are favourable.

568 citations

Book ChapterDOI
TL;DR: This chapter reviews the literature on hemicellulases from 1950 to 1973, and discusses those enzyme preparations that have employed in protein purification procedures, been shown to be homogeneous.
Abstract: Publisher Summary The terms “hemicellulases” or “hemicellulose-degrading enzymes” refer to those enzymes that specifically degrade only hemicelluloses, and do not include the glycosidases—which—in addition to their activity on glycosides of low molecular weight, are also frequently capable of hydrolyzing the short-chain or monosaccharide appendages from the backbone chain of hemicelluloses. Typical hemicellulases are the L-arabinanases, D-galactanases, D-mannanases, and D-xylanases. This chapter reviews the literature on hemicellulases from 1950 to 1973, and discusses those enzyme preparations that have employed in protein purification procedures, been shown to be homogeneous. Fungal, extracellular L-arabinanases have been shown to be inductive and constitutive. Several saprophytic fungi were found by Fuchs and coworkers to produce L-arabinanase inductively but not constitutively, whereas several phytopathogenic fungi were found capable of producing L-arabinanases by induction when grown on Larabinan, and constitutively when these organisms were grown on Dglucose as the sole carbon source.

415 citations

Journal ArticleDOI
TL;DR: Three strains of Clostridium thermocellum obtained from various sources were found to have nearly identical deoxyribonucleic acid guanosine plus cytosine contents that ranged from 38.1–39.5 mole-%.
Abstract: Three strains of Clostridium thermocellum obtained from various sources were found to have nearly identical deoxyribonucleic acid guanosine plus cytosine contents that ranged from 38.1–39.5 mole-%. All strain examined fermented only cellulose and cellulose derivatives, but not glucose, or xylose or other sugars. The principal cellulose fermentation products were ethanol, lactate, acetate, hydrogen and carbon dioxide. Growth of C. thermocellum on cellulose resulted in the production of extracellular cellulase that was non-oxygen labile, was thermally stable at 70° C for 45 min and adsorbed strongly on cellulose. Production of cellulase during fermentation correlated linearly with growth and cellulose degradation. Both the yield and specific activity of crude cellulase varied considerably with the specific growth substrates. Highest cellulase yield was obtained when grown on native cellulose, α-cellulose and low degree of polymerization cellulose but not carboxymethylcellulose or other carbohydrate sources. Cellulase activity was not detected when cells were grown on cellobiose. Crude extracellular protein preparations lacked proteolytic and cellobiase activity. The pH and temperafure optima for endoglucanase activity were 5.2 and 65° C, respectively, while that of the exoglucanase activity were 5.4 and 64° C, respectively. The specific activity at 60° c for exoglucanase and endoglucanase of crude cellulase obtained from cells grown on cellulose (MN 300) was 3.6 μmoles reducing sugar equivalents released per h (unit)/mg of protein and 1.5 μmole reducing sugar equivalent released per min (unit)/mg of protein, respectively. The yield of endoglucanase was 125 units per g of cellulose MN 300 degraded and that of exoglucanase was 300 units per g of cellulose MN 300 degraded. Glucose and cellobiose were the hydrolytic end products of crude cellulase action on cellulose, cellotraose and cellotriose in vitro.

248 citations