جستجوی مقالات مرتبط با کلیدواژه « cellulase » در نشریات گروه « زیست شناسی »

Tannins are a group of polyphenolic compounds that are widely present in plants as an anti-nutritional factor. The rumen of wild ruminants contains novel microbes that detoxify antinutrients and improve feed digestion. The present study evaluated tannase-producing bacteria isolated from the rumen of Fallow deer (Dama dama), livestock potential feed additives. Tannase-producer bacteria (TPBs) were isolated from the rumen using a 2% tannic acid- plate and tannase activity (TAA) assayed by the spectrophotometer method. The bacterial DNA was extracted through boiling and amplified using a PCR reaction. The Sanger technique and BLAST software were used to identify the strains. Antibacterial (ABA) and antibiogram tests were performed by the disc diffusion method, and the acid and bile resistance of isolates were examined using broth cultures. The results indicated that TPBs belonged to Klebsiella, Enterobacter, and Escherichia genera. Escherichia fergusonii GHMGHE44 (9.39 Uml-1) and Enterobacter cloacae GHMGHE26 (1.79 Uml-1) were the strongest and weakest tannin degraders (p<0.01). Among the isolates, bile and acid resistance were insignificant (p>0.01) but E. fergusonii GHMGHE28 (9.48 CFU ml-1) had a significant survival rate compared to E. cloacae GHMGHE25 (9.07 CFU ml-1) at pH of 7 (p<0.01). Also, K. pneumoniae subsp. rhinoscleromatis GHMGHE27 (32.66 mm), E. coli GHMGHE47 (40.66 mm), and E. fergusonii GHMGHE48 (24.66 mm) were potently suppressed the pathogen E. Coli, S. aureus and P. aeruginosa, respectively (p<0.01). Against used antibiotics, E. asburiae GHMGHE22 was the most sensitive isolate while others showed diverse reactions (p<0.01).Discussion and The findings showed that TPBs have the potential to study as commercial animal feed additives (AFA).

Production of fungal cellulase was performed by the isolate of Penicillium expansum MDFS2 on rice straw, rice bran, and wheat straw under solid-state fermentation. The greatest potential growth was detected using rice bran as the carbon source substrate. On the fifth day of fermentation, filter paperase, carboxymethyl cellulase, and β-glucosidase obtained their maximal activities of 4.91 U/g substrate, 36.51 U/g substrate, and 12.21 U/g substrate, respectively. The optimum temperature for filter paperase was reported at 40 °C, whereas carboxymethyl cellulase and β-glucosidase were optimally active at 50 °C. Filter paperase and carboxymethyl cellulase showed maximum activity at pH 5.0. However, β-glucosidase proved to be maximally active at pH 6.0. According to the thermal stability results, all the three components of the cellulolytic enzyme complex proved to be less thermally resistant at 60 °C, as compared to 50 °C. β-glucosidase and carboxymethyl cellulase depicted the highest and the lowest thermal resistance, respectively. β-glucosidase and filter paperase stored for one week at -20 °C proved to be the most and least stable enzymes, respectively. It is hoped that current research findings will help in the cost-effective production of industrially important cellulases using agro-industrial by-products as fermentation substrates.

High antagonistic ability of different Trichoderma species against a diverse range of plant pathogenic fungi has led them to be used as a biological fungicide in agriculture. They can also promote plant growth, fertility, resistance to stress, and absorption of nutrients. They are also opportunistic and symbiotic pathogens, which can lead to the activation of plant defense mechanisms.

The aim of this present study was to investigate possible enhancement of lytic enzymes production and biocontrol activity of T. virens against Rhizoctonia solani through gamma radiation and to find the relationship between changes in lytic enzyme production and antagonistic activity of T. virens.

Dual culture conditions were used to evaluate the antagonistic effect of T. virens and its gamma mutants against R. solani. Then, their chitinase and cellulase activities were measured. For more detailed investigation of enzymes, densitometry pattern of the proteins was extracted from the T. virens wild-type and its mutants were obtained viaSDS-polyacrylamide gel electrophoresis.

The mutant T.vi M8, T. virens wild-type and mutant T.vi M20 strains showed the maximum antagonistic effects against the pathogen, respectively. Data showed that the mutant T. vi M8 reduced the growth of R. solani by 58 %. The mutants revealed significantly different (p <0.05) protein contents, chitinase and cellulase production (mg.mL-1) and activity (U.mL-1) compared to the wild-type strain. The highest extracellular protein production in the supernatant of chitinase and cellulase TFM was observed for the T.vi M11 and T.vi M17 strains, respectively. The T.vi M12 and wild-type strains secretedchitinase and cellulase significantly more than other strains did. Densitometry of SDS-PAGE gel bands indicated that both the amount and diversity of chitinase related proteins in the selected mutant (T. vi M8) were far higher than those of the wild-type. The diversity of molecular weight of proteins extracted from the T. virens M8 (20 proteins or bands) was very high compared to the wild-type (10 proteins) and mutant T.vi M15 (2 proteins).

Overall, there was a strong link between the diversity of various chitinase proteins and the antagonistic properties of the mutant M8.

Cellulase is one of the most commercial and applicable enzymes which is produced chiefly by fungi, bacteria, protozoa and metazoa that catalyze cellulolysis, the decomposition of cellulose and of some related polysaccharides. Recently, the demand for this enzyme has been increased mostly for the various industrial purposes. It has been assumed that the milieu of earthworm’s intestine is the final destination of digestive enzymes such as cellulase. For the first time, this study is aimed to shed a light on the characteristics of cellulase activity in the coelomic fluid and body extract of the earthworm Allolobophora chlorotica. Practically, following the preparation of homogenate and coelomic body in cold-ice and enzyme activities at different conditions were investigated and based on results, the optimum pH and temperature for cellulase activity were pH 9 and 50℃, respectively for the two sources. Given the results, the earthworm contains a novel cellulolytic enzyme which is more stable at alkaline pH. A side from optimal pH and temperature, the addition of metal salts, including CaCl2, NaCl, MgCl2, KCl increase cellulase activity, although, HgCl2 and EDTA have inhibitory effects on the enzyme. Due to common properties of cellulase from coelomic and body extracts it can be concluded that coelomic cellulase contents can be secreted from digestive tracts to facilitate the digestion of the food. Furthermore, based on results, the novel cellulase is active at alkaline pH and moderately thermostable which can be used in biotechnological industries after purification.

Cellulases with capability to have enzymatic functions at low pH and high temperature are ‎‎important and include considerable portion of industrial enzymes. Endo‏-1,4‏‎-β-glucanase is ‎‎one of the three cellulolytic enzymes in a triplet catalytic system that required for ‎extracellular ‎cellulose hydrolysis. In this study, the sampling was performed from four hot ‎springs in north ‎and northwest of Iran and the screening and identification of acid-stable and ‎thermostable of ‎endo‏-1,4‏‎-β-glucanase producing bacteria were investigated. Endo‏-1,4‏‎-β-‎glucanase of the ‎isolated strains were determined by qualitative Congo-Red staining as well ‎as quantitative ‎Carboxymethylcellulose/Dinitrosalicylic acid methods as indicators of ‎cellulase activity. Three ‎isolates out of twelve initially selected bacteria, showed noticeable ‎endo‏-1,4‏‎-β-glucanase ‎activity, including Paenibacillus sp. ASh‏4‏‎ , Bacillus sp. AGh‏1‏‎ and ‎Bacillus sp. AG‏2‏‎ with ‎‏90‏‎%, ‎‏77‏‎% and ‎‏45‏‎% residual activity at pH=‎‏4‏‎ and ‎‏60‏oC after three ‎hours. Molecular identification of the bacteria was carried out using ‎‏16‏S rDNA partial ‎sequencing, ‎in which two isolates belonged to Bacillus sp. and one to Paenibacillus sp.. The ‎results shown ‎that the isolated acido-thermotolerant Bacillus spp. and Paenibacillus sp. had ‎the capability to ‎produce proper acid-stable and thermostable endoglucanase. These isolate ‎also may be even ‎considering as candidates for satisfactory production for other ‎thermostable metabolites with ‎further biotechnological applications‏‎.‎