Identification and Enhanced Production of L-Asparaginase Enzyme Using A Soil-Isolated Fungal Strain: Sarocladium kiliense IBRC-M 30453

L-asparaginase is a significant anticancer enzyme used both in medicine and food industries. Considering the importance of L-asparaginase in different industries, finding new sources of producer strains that can produce higher levels of this enzyme with minimum side effects is preferred.

Initial screening for L-asparaginase-producing strain was performed via qualitative plate assay on modified Czapex Dox's agar medium using L-asparagine as the nitrogen source and phenol red as pH indicator. L-asparaginase activity of the fungal strain was quantified by the nesslerization method. Its identification was performed by using both morphological characteristics and phylogenetic analyses of DNA sequence data, including ribosomal DNA regions of ITS (Internal Transcribed Spacer) and LSU (large Sub-Unit) rDNA. L-asparaginase production was optimized by the One Factor-At-the-Time (OFAT) technique. The impacts of temperature, inoculum size, nitrogen, and carbon sources on the enzyme production were then evaluated.

Sarocladium kiliense IBRC-M 30453 was isolated from soil and identified as a potent enzyme-producing strain. The enzyme production was based on the extracellular mode. An optimum enzyme activity of 62.4 U ml−1 was obtained at the temperature of 25°C with inoculum size of 9% (v/v) and sucrose containing carbon and ammonium chloride as the nitrogen source. The optimization process led to 2.8-fold increase in the enzyme production.

There is a market demand for an alternate source of L-asparaginase with fewer adverse effects due to an increase in the clinical and industrial applications of this enzyme. Fungal L-asparaginase can be the proper answer to the current status of the market. However, application of statistical optimization processes and genetic manipulation have been recommended in other studies to achieve its maximum production level and improve feasibility of its industrial production.