排序方式: 共有42条查询结果,搜索用时 250 毫秒
31.
The extracellular carboxymethyl cellulase (CMCase) was purified 17-fold from Micrococcus roseus, a symbiotic organism of higher termites. Purified CMCase had an M
r of 45 kDa and was optimally active at pH 8.0 and 40°C. Carbohydrate was associated with it and cellobiose was a competitive inhibitor of its activity. 相似文献
32.
芽孢杆菌(Bacillus sp.No.74)大麻脱胶酶系的研究 总被引:3,自引:1,他引:2
研究了Bacillussp.No.74菌株,在以玉米粉为碳源,硫酸铁为氮源,35℃,摇瓶培养24h。经测定产生的脱胶酶系有:果胶酶、木聚糖酶、CMC酶、蛋白酶和α-淀粉酶,不产生β-葡萄糖苷酶和C1酶。经底物亲和性试验和紫外分光光度计测定,证明产生的果胶酶为聚半乳糖醛酸裂解酶,其最适作用pH9.6,温度50℃。对温度的稳定性与它所处介质有极密切的关系。 相似文献
33.
34.
Hiroki Ishihara Kimitoshi Imamura Makoto Kita Tadanori Aimi Yutaka Kitamoto 《Mycoscience》2005,46(3):148-153
Purification and viscometric characterization of three CMCases from Polyporus arcularius were carried out. The three CMCases, I, II, and IIIa, were estimated to have molecular masses of 39.1 kDa, 36.3 kDa, and 24.3 kDa, respectively. The addition of cellobiose and cellooligosaccharides to the reaction mixtures of CMCase I and II inhibited viscometric endocellulase activity. Following the addition of 20 mM cellobiose, CMCase I and II activities fell to about 30%–36% of their activity in the absence of cellobiose. CMCase IIIa activity, on the other hand, increased in proportion to the increase in cellobiose or cellooligo-saccharide concentration. Maximal enhancement of CMCase IIIa activity was observed following the addition of cellobiose, whereas less enhancement was observed with cellooligosaccharides spanning more than two glucoside units. The addition of 20 mM cellobiose resulted in an increase greater than 500% in CMCase IIIa activity. Inhibition of CMCase I and II by cellobiose and cellooligosaccharides may be the result of competition between the substrate and the reaction products. One of the reaction products of CMCase IIIa may bind to a site other than the active site of the enzyme, thus enhancing CMCase IIIa activity. 相似文献
35.
本实验研究分别以淀粉、果胶和纤维素为液体培养基中唯一碳源时,虫草菌所产相应诱导酶活性变化。通过分别以淀粉、果胶和CMC为唯一碳源的液体培养基培养虫草菌,检测培养过程中酶活性变化、残糖及总核苷量。结果表明:分别利用淀粉、果胶和CMC为唯一碳源,虫草菌均能生长并产生诱导酶。淀粉酶活力最高可达40 U/m L,CMC酶活力仅达到1.6 U/m L,果胶酶酶活力达到6.86 U/m L,淀粉酶活力比果胶酶酶活和纤维素酶中的CMC酶活力高很多,淀粉是较容易利用的碳源。淀粉、果胶和CMC培养虫草菌都会产生碱性物质。含淀粉较多的农业加工副产品、废弃物对虫草菌培养的贡献价值较高。 相似文献
36.
M. I. Rajoka 《World journal of microbiology & biotechnology》2005,21(6-7):1063-1066
Summary Deoxyglucose-resistant mutants of Cellulomonas biazotea secreted elevated levels of cellulases and xylanases. The production of β-glucosidase in the constitutive mutant was increased 5-fold over its parent strain. This mutant showed an approximately 1.6-fold
enhanced productivity of extracellular endo-glucanase following growth on Leptochloa fusca over the mutant parent. Extracellular production of xylanase, filter-paper cellulase (FPase) and endo-glucanase (CMCase)
were also altered in the mutant. Maximum volumetric productivities for xylanase, β-xylosidase, FPase, β-glucosidase and endo-glucosidase were 451, 98, 80, 95, and 143 IU l−1 h−1 which were significantly more than their respective values from the parental strains. The enzyme preparation of the mutants
exhibited improved saccharification of kallar grass straw. 相似文献
37.
Food commensal microbes as a potentially important avenue in transmitting antibiotic resistance genes 总被引:5,自引:0,他引:5
Wang HH Manuzon M Lehman M Wan K Luo H Wittum TE Yousef A Bakaletz LO 《FEMS microbiology letters》2006,264(2):226-231
The isolation of cellulosomes from clostridial sources has been extensively studied; however, the isolation of cellulosomes from facultative soil anaerobes of the family Bacillaceae is not as well characterized. The Bacillus cellulosome (celluloxylanosome) essentially consists of two complex components: C-I and C-II. This multi-component complex enables Bacillus to degrade a variety of carbonaceous compounds as it is composed of several enzymes, such as cellulases, xylanases and other degradative enzymes. The cellulosomal cellulases from Bacillus megaterium were purified using cellulose affinity chromatography, followed by Sepharose 4B gel filtration chromatography. The objective of this investigation was to establish the effect of sulfate and sulfide on cellulosomal 'cellulase' activity. An increase in sulfide concentration led to a general enhancement of cellulosomal-associated cellulolytic activity, whereas an increase in sulfate concentration resulted in an inhibition of the cellulosome-associated cellulolytic activity. 相似文献
38.
Pankaj Krishna Amita Arora M. Sudhakara Reddy 《World journal of microbiology & biotechnology》2008,24(12):3079-3085
We have isolated and characterized a xylanolytic actinomycete strain (RM1) from the extremely alkaline bauxite residue obtained
from National Aluminum Company Ltd., Damanjodi, India. The phenotypic features and complete sequence of 16S rRNA revealed
that this strain belong the genus Kocuria and showed 98% sequence similarity with Kocuria
aegyptia. The RM1 strain was able to grow at pH 10.5 in buffered and unbuffered media and utilize 40 different carbon substrates.
The RM1 strain under optimal conditions produced extracellular xylanase at 311 U/ml. The xylanase produced by RM1 showed a
wide range of temperature (30–85°C) and pH (4.5–9) tolerance by retaining 90% of its activity. This is the first report of
isolation of actinomycetes, Kocuria sp., which produces high amount of xylanase, from bauxite residue and offers a new source of xylanase-producing strains. 相似文献
39.
40.
The production of cellulase by Bacillus subtilis MU S1, a strain isolated from Eravikulam National Park, was optimized using one-factor-at-a-time (OFAT) and statistical methods. Physical parameters like incubation temperature and agitation speed were optimized using OFAT and found to be 40?°C and 150?rpm, respectively, whereas, medium was optimized by statistical tools. Plackett-Burman design (PBD) was employed to screen the significant variables that highly influence cellulase production. The design showed carboxymethyl cellulose (CMC), yeast extract, NaCl, pH, MgSO4 and NaNO3 as the most significant components that affect cellulase production. Among these CMC, yeast extract, NaCl and pH showed positive effect whereas MgSO4 and NaNO3 were found to be significant at their lower levels. The optimum levels of the components that positively affect enzyme production were determined using response surface methodology (RSM) based on central composite design (CCD). Three factors namely CMC, yeast extract and NaCl were studied at five levels whilst pH of the medium was kept constant at 7. The optimal levels of the components were CMC (13.46?g/l), yeast extract (8.38?g/l) and NaCl (6.31?g/l) at pH 7. The maximum cellulase activity in optimized medium was 566.66?U/ml which was close to the predicted activity of 541.05?U/ml. Optimization of physical parameters and medium components showed an overall 3.2-fold increase in activity compared to unoptimized condition (179.06?U/ml). 相似文献