OPTIMIZATION OF PROCESS PARAMETERS FOR L-ASPARAGINASE PRODUCTION BY ASPERGILLUS TERREUS MTCC 1782 UNDER SOLID STATE FERMENTATION USING MIXED SUBSTRATE

C.Aparna, K. Jaya Raju

Abstract: L-asparaginase (L-asparagine amido hydrolase, E.C.3.5.1.1) is an extra cellular enzyme that has received considerable attention since it is used as an anticancer agent. L-asparaginase belongs to an amidase group that hydrolyses the amide bond in Lasparagine to aspartic acid and ammonia. The clinical action of this enzyme as an anti-carcinogenic is attributed to the reduction of L-asparagine; tumour cells unable to synthesise this amino acid are selectively killed by L-asparagine deprivation. LAsparaginase has its application in food industry also. It helps in reducing the content of acrylamide in baked food products by hydrolysing the L-asparagine. L-Asparaginase is majorly produced by microorganisms including bacteria, yeast and fungi. The potential of Aspergillus terreus MTCC 1782 using cauliflower stalk: corn ears (3.75: 1.25) as substrate under SSF is the purpose of the study. Solid state fermentation (SSF) is a very effective technique opposed to submerged fermentation in various aspects. Various fermentation parameters such as types of agro material, their ratios, carbon source, nitrogen source, inoculum level, moisture content, temperature, pH, fermentation time, metal salts, and L-asparagine concentration, which influence the rate of enzyme production under SSF, were optimized. The optimized production of L-asparaginase has been obtained at 35°C for 4 days with a pH of 9.0, along with 50% moisture content, and 20% inoculum volume as the optimized fermentation conditions. The optimization was done using a ‘one-factor-at-a-time’ approach. The highest yield was obtained with, sucrose (1%w/v), ammonium sulphate (1%w/v), NaCl (1%w/v), L-asparagine (1%w/w), added to the fermentation medium, as supplements. Use of cauliflower stalk along with corn ear as potential raw materials for enzyme production could be of great commercial significance.

Keywords: L-asparaginase, chemotherapeutic agent, Aspergillus terreus, SSF, mixed substrate, optimization

DOI: https://doi.org/10.15623/ijret.2015.0405067