Pectinase production by Bacillus subtilis on soild state, semi-solid, submerged fermentation modes and its application on coffee fermentation

Abstract

Pectinase is a group of enzymes that degrades pectin substances. This enzyme could be produced by microbial fermentation. In this study, the objective was aimed to choose the most optimal mode of fermentation to produce pectinase by using Bacillus subtilis and investigate conditions of coffee treatment with this enzyme for highest soluble solid content extraction. Pectinase was produced by bacterial fermentation on solid, semi-solid and submerged state. The enzyme activity was determined by anthrone assay. As the result, pectinase achieved from molasses submerged mode with the supplement of 1% of (NH4)2SO4 and 2% of pectin, initial pH 4.5 and incubated at 37oC and for 6 days had the highest pectinase activity at 125.60±6.547 (U/ml). For investigation on optimal conditions for coffee treatment, the highest soluble solid content was 4.26±0.02 (oBrix) with 55% moisture content of coffee beans, 8% enzyme ratio and incubated at 35oC for 24 hours. This result can be used as reference for application in pilot scale or further study. Keywords: Bacillus subtilis, coffee fermentation, semi-solid, submerged fermentation, solid state, soluble solid content, pectinase.