Production of Extracellular Anti-leukaemic Enzyme Lasparaginase from Marine Actinomycetes by Solidstate and Submerged Fermentation: Purification and Characterisation

Abstract

Purpose: The objective of this investigation was to isolate marine actinomycetes, screen them for Lasparaginase activity and characterise the enzyme.Methods: Marine actinomycetes were isolated from sediment samples obtained from Tamilnadu and Kerala in India. The isolates were identified as actinomycetes by microscopical and biochemical tests.Production of L-asparaginase was carried out in three different media, namely, solid-state media, Tryptone Glucose Yeast extract (TGY) broth and Tryptone Fructose Yeast extract (TFY) broth.. The enzyme was purified to near homogeneity by ammonium sulphate precipitation, dialysis, gel filtration on Sephadex G-100 column and SDS-PAGE.Results: Among 10 marine isolates subjected to preliminary screening, only isolates S3, S4 and K8 showed potential for L-asparaginase activity. All three marine soil isolates synthesized asparaginase with yield ranging from 24.6 to 49.2 IU/ml. Soil isolate S3 showed the highest productivity of 49.2 IU/ml with a protein content of 65 μg/ml and optimum activity at pH 7.5 and 50 ºC. The apparent Km value for the substrate was 25 μM. Mg2+ ion slightly stimulated activity while Cu2+, Zn2+ and EDTA were inhibitory.Conclusion: The study revealed that marine actinomycetes may be a potential source of high yield, high substrate specificity L-asparaginase, which is an anti-leukaemia agent.