Statistical Optimization of Pectinase Biosynthesis from Orange Peel by Bacillus licheniformis Using Submerged Fermentation

Abstract

Agricultural, fruit and vegetable wastes were investigated as cost effective source for pectinase production. Orange peel proved as the best inducer of pectinase in a very simple culture medium used. Optimization of various cultural parameters was carried out by statistical method using response surface methodology and central composite design. The basic aim was to find out the best among local agri-wastes for maximum production of pectinase keeping in mind the agro-based economy of the country. Also the aim was to find the best pectinase of alkaline and thermophilic nature having maximum activity in minimum time, to be used in various industrial processes mainly textile industry which is the key industry in a country like Pakistan. The Bacillus licheniformis used in the present study was of special worth as it gave maximum pectinase activity of 219 U/ml in submerged fermentation, in a very simple medium with very few components (NaNO3, KH2PO4, KCl, MgSO4, Tryptone and Orange peel) under optimum conditions of pH 9.5, when incubated at 37 °C for 120 h in an alkaline culture medium of pH 9.5 supplementing with 0.3 % inoculum, 2.5 % orange peel and 0.5 % tryptone. The enzyme exhibited thermophilic nature by showing maximum activity when incubated with substrate (0.5 % citrus pectin solution pH 8.0) at 70 °C for 10 min. The study proved that orange peel has nutrients that enabled the microorganism understudy to produce high quantity (219 U/ml) of pectinase in very simple medium and can be better option for pectinase production on large scale for commercial use in industries.