L-Asparaginase producing ability of Aspergillus species isolated from tapioca root soil and optimized ideal growth parameters for L-Asparaginase production

Abstract

This research was designed to isolate the predominant L-asparaginase-producing fungus from rhizosphere soil of tapioca field and assess the suitable growth conditions required to produce maximum L-asparaginase activity. The Aspergillus tubingensis was identified as a predominant L-asparaginase producing fungal isolate from 15 isolates, and it was characterized by 18S rRNA sequencing. The L-asparaginase-producing activity was confirmed by pink color zone formation around the colonies in modified Czapek Dox agar plate supplemented with 1% L-Asparagine. The optimal growth conditions required for the L-asparaginase production by A. tubingensis were optimized as pH 6.0, temperature 30 °C, glucose as carbon source, 1.5% of L-Asparagine, ammonium sulphate as nitrogen source, rice husk as natural L-Asparagine enriched source, and 8 days of the incubation period. The L-Asparaginase activity from A. tubingensis was excellent under these optimal growth conditions. It significantly used rice husk as an alternative to synthetic L-Asparagine. As a result, this may be considered a sustainable method of converting organic waste into valuable raw material for microbial enzyme production.