Int. J. Pharm. Sci. Rev. Res., 31(2), March – April 2015; Article No. 29, Pages: 173-176 ISSN 0976 – 044X International Journal of Pharmaceutical Sciences Review and Research Available online at www.globalresearchonline.net © Copyright protected. Unauthorised republication, reproduction, distribution, dissemination and copying of this document in whole or in part is strictly prohibited. © Copyright pro 173 P. V. KamalaKumari* 1,2 , G. Girija Sankar 1 , T.Prabhakar 1 1 A. U. College of Pharmaceutical Sciences, Andhra University, Andhra Pradesh, India. 2 Vignan Institute of Pharmaceutical Technology, Visakhapatnam, Andhra Pradesh, India. * Corresponding author’s E-mail: kamalaparavastu@gmail.com Accepted on: 13-02-2015; Finalized on: 31-03-2015. ABSTRACT Strain improvement studies were conducted for the production of L-asparaginase from a marine fungus Beauveriabassiana SS18/ 14 by employing physical and chemical mutagens, in a systemic manner to obtain mutants that have higher L-asparaginase production. The wild strain produced 6.32 IU/mL of L-asparaginase activity while the UV mutant UVF-4 yielded 8.34 IU/mL and nitrous acid mutant UVF4-N-2 exhibited 10.44 IU/ mL enzyme activity. The overall strain improvement programme increased L-asparaginase activity 1.65 times with respect to the parent wild strain. Keywords: Physical mutagens, chemical mutagens, L-asparaginase, Beauveriabassiana INTRODUCTION umor cells, more specifically lymphatic cells, require huge amount of asparagine to maintain their rapid malignant growth. This means, they use both asparagine from the diet (blood serum) as well as what they can make themselves (which is limited) to satisfy their large L-asparagine demand. L-asparaginase as a drug exploits this unusually high requirement for the amino acid asparagine in tumor cells. L-asparaginase catalyzes the hydrolysis of L-asparagine to L-aspartic acid and ammonia. 1,2 as shown in Figure 1. Healthy cells however escape unaffected, as they are capable of synthesizing asparagine themselves with the help of the enzyme L-asparagine synthetase, which is present in sufficient amounts. Figure 1: Mechanism of action of L-asparaginase L-asparaginase arrests cell cycle in the G1 phase which was reported in the murine L5178Y cell line 3 and the MOLT-4 human T-lymphoblastoid line 4 resulting in apoptosis. A human acute lymphoblastic leukemia cell line is markedly inhibited by asparaginase, the effect being 10-fold higher for Erwiniacaratovora L- asparaginase. 5 It has been reported that there is a requirement of a functional p53 protein for L- asparaginase to produce apoptosis as observed in studies on HL60 pro myelocytic leukemia cell lines. 6,7 However, another finding has strongly contradicted the general thought that the therapeutic benefit of L-asparaginase in leukemia is based on the fact that leukemic cells lack sufficient asparagine synthetase compared with normal cells. Strain improvement is an essential part of process development for fermentation products. Developed strains can reduce the costs with increased productivity and can possess some specialized, desirable characteristics. Such improved strains can be achieved by inducing genetic variation in the natural strain and subsequent screening. Mutation is the primary source of all genetic variations and has been used extensively in industrial improvement for production. The use of mutation and selection to improve the productivity of cultures has been strongly established for over fifty years and is still recognized as a valuable tool for strain improvement of many microorganisms. In the present study both physical (UV) and chemical (HNO2) mutagens were employed in systemic manner to obtain mutants that gave higher L-asparaginase production. For UV irradiation, method 8 was adopted. For chemical mutagenesis using HNO2 method 9 was followed. The parental strain SS18/41 was treated with mutagens UV and HNO2 consecutively. M ATERIALS AND M ETHODS UV irradiation of parent strain SS18/ 41 and selection of mutants Strain improvement for the strain SS18/41 was done by mutation and selection. The strain was subjected to UV irradiation. The dose survival curve was plotted for selecting the mutants between 15% and 1% survivals. Mutation frequency was mentioned to be high when the survival rates were between 15 and 1%. Strain Improvement Studies for the Production of L-Asparaginase by Beauveria Bassiana SS18/ 41 T Research Article