Study on extraction methods for protease production from Sterblus asper

Abstract

Streblus asper leaves were collected and used as a plant source for extracting protease enzymes. The enzyme was extracted by three methods and the activity of each extract was determined. Streblus asper leaves were extracted by using three methods which is extraction by phosphate buffer, extraction by distilled water and extraction with ammonium sulphate precipitation. Protein assay was carried out to determine the activity of enzyme for each type of the extraction method. The results showed that maximum enzyme activity (p<0.001) was obtained from Streblus asper leaves extracted with phosphate buffer solution. The enzyme activity significantly decreased (p<0.001) from 1.279 U/mL to 0.406 U/mL when Streblus asper was extracted with ammonium sulphate precipitation and decrease to 0.298 U/mL when Streblus asper was extracted with distilled water. This method was selected for optimization and three parameters have been chosen to investigate enzymatic activity by response surface methodology. An empirical quadratic model was applied to experimental data pertaining to the average enzymatic activity and equation describing the optimal conditions was obtained. As a conclusion, extraction by phosphate buffer produces most protease activity where the maximum enzyme (2.244 U/mL) was obtained in pH 7, 37.5ºC incubation temperature and 4 minutes homogenized time.