PRODUCTION OF ALKALINE PROTEASE BY A NOVEL ANAEROBIC BACTERIUM ISOLATED FROM A MUNICIPAL ANAEROBIC TREATMENT SYSTEM

Abstract

In this study, alkaline protease enzyme production by a bacterial strain isolated from sludge samples collected from an anaerobic treatment system was investigated. According to the 16S rDNA sequence analysis, the isolate was identified as Thermoanaerobacter thermohydrosulfuricus (98.52%). Enzyme activity analyses revealed an optimum pH value of 10, an incubation time of 64 h, and a temperature of 35°C. Arabinose and casein hydrolysates were found to be the best carbon and nitrogen sources, respectively. Maximum protease activity was recorded (864.68 U/mL) when arabinose was used instead of glucose. Moreover, the addition of 1 g/L MgSO4.7H2O and 0.25 g/L Tween-80 to the medium increased the enzyme activity. Therefore, it can be concluded that T. thermohydrosulfuricus is a significant producer of alkaline protease enzymes in the culture medium. To the best of our knowledge, this is the first study to investigate the optimization of alkaline protease production by T. thermohydrosulfuricus.