Cassava Retting Water: An Alternative Source for Industrial Cellulase (Enzyme)

Abstract

Cassava fermentation is one of the teaming businesses in almost all the tribes of Nigeria. Among all the methods of cassava processing to food, fermentation is the most used. This produces foul smelling wastewater that causes environmental pollution to man and animals. The retted cassava water was checked for cellulase (enzyme) activity to see if it can be a source of cellulase for used in food, paper, textile and other industries. The aim of this work is to seek a way of utilizing the wastewater as source of enzymes as this will reduce the importation of these enzymes and make them available always. Cassava tubers were peeled, cut into cylindrical portions of about 3-5 cm and washed. Two hundred grams of the washed tubers were soaked in 5 liters of water and allowed to ret. The retting water was analyzed daily for titratable acidity, cyanide content, pH, cellulase activity and the microbial flora were isolated and identified. Results showed that titratable acidity rose from 0.20 to 2.76 mg/g and cyanide content increased from 0.28 to 4.69 mg/ml while pH fall from 7.2 – 6.0 tending acidic. Retting started on the 2nd day and complete retting was achieved on the 4th day. β-glucosidase activity rose from 0.05 to 8.0 µ/mol, Filter paper activity increased from 0.06 to 7.5 µ/mol and carboxyl methyl cellulase (CMC) activity increased from 0.05 to 7.7 µ/mol. Ten organisms (Aspergillus fumigatus, Rhizopus stolonifer, Bacillus subtilis, Candida utilis, Citrobacter sp, Enterobacter aerogenes, Lactobacillus coryneformis, Saccharomyces cerevisiae, Staphylococcus aureus, Streptococcus feacalis) were isolated from the retting water. Daily increase in the enzyme activities showed that cassava retting when done in a large scale can yield large quantity of enzymes. This will reduce the importation of industrial enzymes and reduce the environmental pollution caused by the wastewater.