Production and characterization of pectinases obtained from Aspergillus fumigatus in submerged fermentation system using pectin extracted from mango peels as carbon source

Abstract

Pectinase was obtained from Aspergillus fumigatus in a submerged  fermentation system using pectin extracted mango peels as a carbon source and subjected to a two step purification system of 80% ammonium sulphate saturation and dialysis. Pectin was also extracted from mango peels and its extraction yield was found to be 17% at pH 2.2, temperature of 70¢ªC and extraction time of 1h. The protein concentration in the crude enzyme was found to be 1.372mg/ml. The specific activity of crude  enzyme is 11.20¥ìmole/min/mg. After 80% ammonium sulphate  precipitation and dialysis, the specific activities were 11.78¥ìmole/min/mg and 34.60¥ìmole/min/mg respectively. The maximal activity of A. fumigatus pectinase was at 40¢ªC, pH 5.5 and was heat stable up to 40¢ªC.Vmax and Km values were found to be of 625¥ìmole/min and 45.5mg/ml respectively. The pectinase was used to degrade pectins extracted from orange and pineapple peels and its specific activities were found to be 30U/mg and 28.39U/mg respectively as compared to 34.60U/mg which is the specific activity obtained when pectin extracted from dry mango peels was used.

Key words: Mango peels, pectinase, pectin, Aspergillu fumigatus, submerged fermentation.