Effect of Organic Solvents and Osmolytes on Extremely Halotolerant and Thermostable α-Amylases from Chromohalobacter sp. TVSP 101

The effect of some organic solvents such as (dimethylsulfoxide (DMSO), N, N-dimethyl formamide (DMF), benzene, toluene, cyclohexane, n-hexane, alcohol, acetone, isopropanol, acetonitrile, butanol, chloroform) and osmolytes (sucrose, betaine, trehalose, mannitol and glycerol) was studied on the activity and stability of an extremely halotolerant and thermostable amylase I and amylase II secreted by Chromohalobacter sp. TVSP 101. The amylases were stable in alcohol and acetone and they were activated 1.5 fold by acetonitrile and isopropanol respectively. Acetonitrile and isopropanol were more effective in preserving the enzymes activity and stability in absence or presence of NaCl. Both amylases were retained more than 60% activity in presence of benzene, toluene, n-hexane and cyclohexane at different concentrations 10–40% (v/v). On the other hand DMF, DMSO and butanol decreased the enzymes activity by more than 90%. The two amylases were active in presence of 15% sucrose, betaine, trehalose and mannitol retaining more than 90% activity. The amylases from Chromohalobacter sp. TVSP 101 are solvent and osmolyte tolerant enzymes, and are an ideal choice for applications in industrial process containing organic-solvents and/or, osmolytes and salts.