A Rapid and Efficient Dye Based Plate Assay Technique for Screening of L-Asparaginase Producing Fungal Strains

L-Asparaginase enzyme has received great attention owing to its potential as anticancer drug and food processing agent. L-Asparaginase producing microbes are conventionally screened on phenol red plates containing L-asparagine as the sole nitrogen source for its growth. However, the contrast of the zone in phenol red plates is not very distinct. To overcome this problem, an alternate methodology for the screening of fungal strains producing extracellular L-Asparaginase is required. In the present comparative investigation, an improved method for screening is reported, wherein Alizarin Red S and 4-Nitrophenol are implied as pH indicator. Plates containing Alizarin Red S and 4-nitrophenolare colorless at acidic pH, turns pink and yellow respectively at alkaline pH. Thus, a dark pink and yellow zone is formed around microbial colonies producing L-asparaginase, differentiating between enzyme producers and non-producers. Thus, we report Alizarin red S and 4-Nitrophenol can detect the production of the anticancer enzyme at a much lower dye concentration which appear to be more accurate and distinctive than the conventional method for the screening of fungi producing extracellular L-Asparaginase.