The Purification and Characterization of Produced L-Asparaginase from Streptomyces Avermitilis Isolated from Marine Environment in Lagos, Nigeria

Abstract

Asparaginase is an enzyme that is used as a medication and in food manufacturing. In medicine, it is used in the treatment of acute lymphoblastic leukemia, acute myeloid leukemia and non-Hodgkin's lymphoma, administered through the vein, muscle or under the skin. This study carried out purification and characterization of produced L- asparaginase from Streptomyces avermitilis isolated from marine environment. Samples were collected from Atlantic ocean Lagos, Nigeria and production of L -asparaginase was carried out in Erlenmeyer flask containing Czapek Dox broth supplemented with L-asparagine (1 g/L), as production medium for 3 days at 120 rpm and at 28 0C. A 5 % inoculum was used. Crude extract of produced L asparaginase was obtained by centrifuging at 10,000 rpm for 5 min using a cold centrifuge. Precipitation of crude extract was carried out using 60 % ammonium sulphate. Dialysis, ion exchange chromatography, and gel filtration were used to carry out the complete purification process. The effect of substrate concentration, pH, temperature, incubation time, and metal ions was studied to characterize the enzyme. Results revealed the maximum velocity of purified L-asparaginase as 51.136 µmol/min/ml and Km value was 3.812 µmol. The highest enzyme activity was recorded at pH 6.0 and at a temperature of 40 0C. The purified enzyme had a half-life of 50 minutes at 60 0C and was inhibited by urea. Metals such as Mn2+, Co2+, and Hg+, had a significant increase in purified L-asparaginase activity. In conclusion, the purified enzyme showed viability under various conditions in the study carried out.