RANDOM MUTAGENESIS BY NTG TO INCREASE PROTEASE ACTIVITY OF LYSOBACTER ENZYMOGENES

Background and Aim:Proteases are a large group of enzymes which have many uses in medicine and industry. These enzymes could be extracted from various microorganisms. Today, strain improvement of producer strains is in the center of attention in the commercial scale. Endopeptidase Lyse C extracted from Lysobacter enzymogenes, is widely used in the sequencing of proteins. So in the present study, random mutagenesis by chemical method was employed in order to enhance protease production of L.enzymogenes strains.Methods:L. enzymogenes strain ATCC 29487 was obtained and cultured on the nutrient agar medium at 33 °C for 48 h. A mutagenic technique using the chemical mutagen nitrosoguanidine (NTG) was applied to isolate mutants with more protease production rate. The bacterial strains were exposed to various concentrations of NTG (100, 150 and 200 μg/ml) for 20 and 40 min. In the next step, screening was done by culturing L. enzymogenes on the nutrient agar medium containing casein. The enzyme production was determined by measuring the halo zone diameter caused by casein lysis via protease enzymes, and quantitatively examined with Folin & Ciocalteus phenol reagent.Results:It was found that NTG mutagenesis was effective for increasing the production of protease enzyme in some mutated isolates.Conclusion:Random mutagenesis by chemical method (NTG) was an effective way for increasing protease production in Lysobacter enzymogenes.

کلیدواژه ها:

Lysobacter Enzymogenes ، chemical mutagenesis ، nitrosoguanidine (NTG)