Production and characterization of bacterial thermophilic avicelase

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.