Production and Partial Characterization of Cellulases from Apergillus fumigatus Using Two Distinct Parts of Corn Cob as Carbon Sources

Abstract

Corn cobs were sun-dried for three days and separated into the hard outer part (Corn Cob Outer, CCO) and the soft inner part (the pulp) (Corn Cob Inner, CCI). Each part was milled separately. Aspergillus fumigatus isolated from sewage water was grown on and adapted to each part of corn cob. Using CCI and CCO, as the sole carbon sources for submerged fermentation, the organism produced cellulase. Activity was highest on the 3^rd and 4^th days using CCI and CCO, respectively. The crude cellulases were partially purified by 50% ammonium sulphate precipitation followed by dialysis. The partially purified cellulases were then characterized with respect to pH, Temperature and Themostability. While the optimum pH of the CCI cellulose was 6.0, that of CCO cellulase was pH 7.0. The optimum temperature of CCI was 55°C whereas that of CCO was 50°C. The stability of enzymes from 35°C to 70°C was studied. At 70°C, CCO cellulase has lost 45.88% of its original activity while CCI cellulase lost 58.14%. The results show that corn cob could serve as a cheap carbon source for the production of fungi cellulase. The study indicates that waste could be converted to wealth.

Key words: Corn cob, cellulose, Aspergillus fumigates, submerged fermentation, partial purification