Study on pectinase production by bacillus subtilis in molasses and its application for coffee fermentation

Abstract

Pectinase also well-known terms for commercial enzyme preparation that have wide application, however, the high cost used in the importation of industrial extracellular enzymes has led to the high cost of finished industrial products. This thesis was aimed to study the suitable condition to produce pectinase by using Bacillus subtilis fermentation in molasses medium including the pectin substrate concentration in molasses, pH, and incubation time for the purpose of reducing production expense. The enzyme activity was determined by measuring the absorbance at λ = 540 nm with 3, 5-DNS reagent. As the result, pectinase achieved from molasses with the supplement of 1% of (NH4)2SO4 and 3% of pectin substrate, initial pH 5 and incubated at 37oC and for 5 days had the highest pectinase activity at 76.91±0.15 (U/ml). Then, the crude pectinase were applied on de-mucilage of coffee layers; investigate conditions of coffee fermentation for highest soluble solid content extraction. For coffee treatment, the highest amount of removed mucilage was 62.97%, with 3% (v/w) crude enzymes incubated at 35oC for 2 days (48 hours) and was 2.9 times higher than these amount of the control. The highest soluble solid content was 4.01±0.08 (oBrix) with 50% moisture content of coffee beans, 3% enzyme (v/w) and incubated at 35oC for 36 hours. This result can be used as reference for application in pilot scale or further study.