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

Cellulases are important industrial enzymes for the most bioconversion processes. In this study, Bacillus aerius isolated and identification as the best thermophilic cellulose degrading bacterium from Gorooh hot spring and was identified as Bacillus aerius AV10 based on 16S rRNA sequence homology and microbial- biochemical tests. Cultivation conditions of cellulase production by Bacillus aerius AV10 in solid-state fermentation (SSF) were investigated. The moisture content, yeast extract, MgSO4 and initial culture pH were identified by Plackett-Burman design (PBD) as the significant factors for endoglucanase, exoglucanase and filter paper (FPA) activities. Response surface Methodology and central composite design by 5-level and 4-factor were used for the optimization of enzyme. The optimal ranges of moisture content, yeast extract, MgSO4 and initial culture pH were 61.4%, 1.65%, 0.29% and 6.2, respectively. Under the optimized conditions, maximum CMCase production was 561.12 U/ml. The optimal pH and temperature of the enzyme for wheat straw hydrolysis were determined to be 7.0 and 60 °C.

Production and characterization of bacterial thermophilic avicelase Fatemeh Azadian, Arastoo Badoei-dalfard*, Abdolhamid Namaki-Shoushtari, Mehdi Hassanshahian Department of Biology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran Nowadays, developing processes for effectively converting agricultural wastes for production of high value chemicals has gained considerable interest. Avicelases are important industrial enzymes for the most bioconversion processes. In this study, samples were picked up and inoculated in AVI broth for 7 days at 50 ºC. The bacterial strains with the clear halo (represent extracellular avicelase) have been purified. AV8 isolate which showed the highest clear halo was selected for further studies. This strain was identified as Bacillus genus based on biochemical tests and 16S rRNA analysis. Avicelase production was considered under varying environmental parameters. The best carbon and nitrogen sources for maximum avicelase production were 0.5% sucrose and 0.25% yeast extract, respectively. Avicelase from this strain has been partially purified using ammonium sulphate fractionation followed by dialysis and ion exchange Q-Sepharose chromatography. Results showed that enzyme was active and stable between 30-70 ºC and itʼs maximum temperature activity was observed in 70 ºC. The optimum avicelase activity and stability was observed at pH 6.0. These are characteristics indicating that this enzyme could be an acidophilic and thermophilic avicelase. Furthermore, the avicelase activity improved by methanol (138 %) and chloroform (107 %). These results indicated that AV8 avicelase has potential applications in various industries.

Amylolytic enzymes are among the most important enzymes in food, pharmaceuticals, detergent industries and biotechnology. Alpha amylases cleave the linkage between adjacent glucose units in the linear amylose chain and ultimately generate glucose, maltose and maltotriose units. Although many microorganisms such as Bacillus licheniformis, Bacillus amyloliquifaciens produce this enzyme, Aspergillus niger as most popular one is used in industrial applications. In the present study, a strain of amylolitic Anoxybacillus sp. was identified. 16SrDNA analysis was carried out and bacterial optimal growth and production was investigated. Moreover, enzyme was partially purified and biochemical properties such as temperature, optimum pH and the effect of denaturants like SDS on the stability of enzyme were evaluated. On the other hand, encoded gene of enzyme was amplified and sequenced. Results indicated that after 20 hours, the optimal conditions for bacterial growth were at 60ºC and pH of 7. Also, maximum enzyme activity was obtained at 75ºC at pH 6 after 72 h of incubation. Enzyme showed higher optimum temperature but similar stability against SDS in comparison with other similar.

Aim and The aim of this study was identification and isolation of thermophilic bacteria from Dalaky hot spring located in Boushehr province by using of biochemical and molecular methods and considering of enzymatic properties, anti-bacterial and anti-fungal of isolated strains. Sampling from surface water, sludge and depth of one meter was carried out in sterile conditions.Samples were incubated for a week, then grown Bacteria were purified. Identification was done by using of biochemical and molecular methods. Antibacterial properties against Eshershia coli bacteria and Staphilococcus aureus by turbidometery method and antifungal properties against Aspergillus niger based on the power of inhibitory were studied. 12 strains (A1-A12) were isolated and purified. A1, A8, A9, A11 strains, can tolerate 20% sodium chloride salt. A1 and A11 strains are capable of growth at pH 3-12 and at temperatures of 20-56 ° C.The results of antibacterial effect against S. aureus strains showed that with increasing concentration of strain extract from % 5 to 20% in A5, A6, A7, A10, A11, A9, A12 strains, the antibacterial properties increased significantly. while just A12 strain prevented the growth of E-coli in concentration of 20%.The most effective strains against Aspergillus were A2 and A6. As A11 strains can grow in a wide range of temperature, pH, as well as the superior ability of antagonistic 16SrDNA coding region was sequenced. According to this A11 strain with 98% similarity was identified as Bacillus subtilis subsp. spizizenii strain NRRL. Because of anti-fungal and anti-bacterial effect, thermophilic bacteria is an excellent option in the treatment of bacterial diseases,in future studies.