L-asparaginase and L-glutaminase from Aspergillus fumigatus WL002: Production and some physicochemical properties

Abstract

A fungal strain isolated from the soil of coastal region of Bay of Bengal (India) was identified as Aspergillus fumigatus WL002 and had been found to be capable of producing extracellular L-asparaginase and L-glutaminase. Maximal production of both enzymes was observed at 37°C, pH 5.0 and incubation time 96 h in solid-state fermentation process in the medium with wheat bran. The optimum temperature, pH and K m for L-asparaginase activity (substrate L-Asn) were found to be 50°C, 9.0 and 7.02 mM, respectively, and those for L-glutaminase activity (substrate L-Gln) were 50°C, 9.5 and 5.74 mM, respectively. Both the enzymes were thermostable. It was revealed that even after incubating at 50°C for 1 h, L-asparaginase and L-glutaminase retained 98.8 and 90.6% of the activity, respectively, but the enzyme activity decreased sharply with further increase in temperature.