A novel Antitumour L Asparaginase from marine Streptomyces SP STRAIN EPD 27 identification purification characterization and fermentation kinetics of enzyme production

Abstract

L-asparaginase (L-asparagine amidohydrolase E.C.3.5.1.1) is an effective antineoplastic enzyme, used in acute lymphoblastic leukemia (ALL) chemotherapy. L-asparaginase activity of marine actinobacteria in sediments of Parangipettai, East coast region of India was investigated. Thirty four actinobacteria were isolated from the sediments of Parangipettai in different selective media. Nalidixic acid and seawater were found to be important in enrichment of sediments for the increase of actinobacteria count. Starch casein agar and Glucose asparagine agar are found to be suitable media for the isolation, growth and maintenance of marine actinobacteria. Qualitative and quantitative assays were done for the screening of L-asparaginase activity of marine actinobacteria. Out of thirty four isolates, seven were found to produce L-asparaginase. Among them, the strain EPD 27 produced high amount of L-asparaginase. Hence it was selected for the further identification. The strain EPD 27 was identified by using a combination approach which includes classical and molecular methods. For purifying and obtaining a homogenous L-asparaginase from the strain EPD 27, a modified purification procedure was adapted in this study. Various characteristics of the enzyme were studied with respect to the therapeutic potential. For the purpose of obtaining the antitumour L-asparaginase in large quantities from strain EPD 27, cell growth and enzyme production were investigated in batch fermentation. The optimum pH and temperature for the production of L-asparaginase was found to be 8.5 and 30 ºC respectively. Using L-asparagine as a growth limiting substrate, the relationship between the specific growth and substrate concentration was found to fit the Monod equation. The results obtained in the present study are in good agreement with the criteria for an antitumour enzyme. newline