Enzymatic Activities Of Species Of Microorganisms Associated With Cassava Retting

ABSTRACT

The enzymatic potentials of microorganisms isolated from retting cassava were evaluated for the purpose of cellulase and amylase activities. Cassava tubers of 12 months old were collected from 3 different sources: Ahieke, Ndoru, Umudike, Awawom and Umuariga in Abia State. They were hand peeled, cut into cylinders, washed, submerged into water and allowed to ret. After retting a dilution of the retted tubers was inoculated into different media plates: De-Man Rogosa Sharp agar, Sabouraud Dextrose agar, Nutrient agar, Mannitol salt agar and MacConkey agar. Thirty- Five (35) isolates were identified in the retting cassava samples which were bacteria 25(71.43%) and fungi 10 (28.57%). The bacterial isolates identified include Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Lactobacillus spp and Proteus spp while fungi isolated were Aspergillus niger, Rhodotorula spp and Saccharomyces cerevisiae. The total viable counts of the isolates increased as the retting hours increased. Lactobacillus spp and Saccharomyces cerevisiae dominated the later stage of the fermentation. Bacillus subtilis has the highest percentage occurrence 8(22.9%) while Rhodotorula spp has the lowest percentage occurrence 2(5.7%). The production of amylase enzyme was recorded with all the isolates with the exception of Staphylococcus aureus. Production of cellulase and pectinase enzymes was selective among the isolates. Results from this study shows that enzymes like amylase, pectinase and cellulase from microorganisms played an important role in retting of cassava tubers.