Improving the nutritive value of cassava peels and cassava root sieviate through biodegradation with aspergillus Niger

This paper discusses the effects of process parameters on the biodegradation of cassava peels and cassava root sieviate through the action aspergillus niger. The ability of aspergillus niger to increase the crude protein content and decrease the crude fiber content of the cassava wastes was investigated with time and substrate concentration as process parameters. Face–centered central composite design (FCCCD) of the experiment was applied in the determination of the two-parameter improvements of the nutritive value of the wastes. The experiment was designed in minitab version 16.0 while the analysis of variance (ANOVA) SPSS 16.0 was applied in the analysis of the raw data. The experimental data analysis showed that the crude protein percentage contents of the two wastes significantly increased, from 4.85 to 15.86 and from 1.85 to 9.42 for the cassava peels (CP) and cassava root sieviate CRS) respectively due to the action aspergillus niger. Similarly, crude fiber was decreased from 68.2% to 7.82% and 70.3% to 8.30% for CP and CRS. These remarkable improvements on the nutritive value the cassava wastes were recorded at an optimum time of 10 days and substrate concentration of 0.6g/ml. From the results, it was obvious that Aspergillus niger was able to enrich the protein while decreasing the fibre contents of the cassava wastes significantly (P<0.05). However from the interaction plots and multiple comparison tests, 6 days of biodegradation and 0.2g/ml substrate concentration have the optimum desirable effect.