Abstract
The Amycolatopsis cihanbeyliensis Mut43, which is obtained by UV radiation, exhibited endoglucanase activity of 5.21 U/mL, which was ∼2.3-fold higher than that of the wild strain (2.04 U/mL). The highest enzyme activity was obtained after 3 days of incubation at 32 °C, pH 7.0, 150 rpm, and 6% NaCl in a liquid medium containing 1.5% (w/v) wheat straw (0.25 mm of particle size) and 0.6% (w/v) yeast extract. Enzyme activity was eluted as a single peak (gel filtration chromatography), and Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) analysis of the corresponding peak revealed a molar mass of 30 kDa. Zymogram analysis confirmed the presence of a single active endoglucanase component. The enzyme was purified to ∼21-fold, and the mean overall yield was ∼6%. The purified endoglucanase was active up to 80 °C and showed a half-life of 214 min at 60 °C in the absence of substrate at pH 8.0. The apparent Km value for the purified endoglucanase was 0.70 mg/mL, while the Vmax value was 6.20 Units/μg. Endoglucanase activity was reduced (25%) by treatment with 30 U of proteinase K/mg. The addition of Mg+2 and Ca+2 (5 mM) enhanced endoglucanase activity. Additionally, endoglucanase activity in the presence of 5 mM SDS or organic solvents was 75 and 50% of maximum activity, respectively. The high levels of enzyme production from A. cihanbeyliensis Mut43 achieved under batch conditions, coupled with the temperature stability, activity over a broad pH range, relatively high stability (70–80%) in the presence of industrial laundry detergents and storage half-lives of 45 days at +4 °C and 75 days at −20 °C signify the suitability of this enzyme for industrial applications as detergent additive.
Disclosure statement
The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.