Survey for extremozymes in halophilic bacterial isolates from Khur and Biabanak Salt Lake

Introduction: Various industrial processes carry out under certain circumstances like high salinity, high temperature and presence of organic solvents that are not optimum values for enzyme activity. Extremozymes are a group of enzymes that are active in these harsh conditions. Halophiles are most likely source of these enzymes, because they are not only salt loving, but also persist at high temperature and organic solvents. Hypersaline lakes are very productive and high microbial richness observed in these environments. The following research focuses on screening extracellular hydrolyses in the indigenous halophilic bacteria from Khur and Biabanak salt lake.Material and Methods: Samples including soil, brine and sediments were collected from Khur and Biabanak Salt Lake. Isolation of bacteria was carried out on different media supplemented by various amounts of salt. In order to detect the production of extracellular hydrolases such as proteases, amylases, lipases, DNase, cellulase (CMCase), pectinase and xylanases, different enzymatic agar plate assays were performed except of urease activity was performed in liquid medium.Results: We obtained 178 bacterial isolates (109 Gram-positive rods, 33 Gram-negative rods and 36 Gram positive cocci). Different 50 strains were selected by preliminary morphology and physiology analysis and the ability to produce nine different hydrolases was tested quantitatively. A total of 18, 23, 1, 16, 6, 19, 24, 13, 29 halophilic isolates were able to produce proteases, amylases, lipases, DNase, cellulase (CMCase), pectinase, xylanases and urease respectively. One strain presented 6 hydrolytic activities and 6 strains presented only one hydrolytic activity.Conclusion: The obtained results showed salt-loving bacteria are good candidate for producing extracellular hydrolyses. Further analyses of secondary screening studies are in progress

کلیدواژه ها:

Halophilic bacteria ، Extracellular hydrolyses ، Khur and Biabank