Aro et al., 2012. Livest. Res. Rural Dev., 24 (3)

Cassava is grown mainly for its tuberous roots whose high carbohydrate content is a cheap source of food that has continued to support the sustenance of millions of people in sub-Saharan Africa, Central America and south-east Asia. The utilization of cassava roots for human consumption and in the industries has led to the generation of different types of wastes aptly called the cassava tuber wastes (CTW). Two of such wastes: the cassava starch residues (CSR) and the cassava peels (CAP) were collected from a cassava starch producing factory, subjected to various forms of solid substrate fermentation with a consortium of micro-organisms and analyzed for their proximate and amino acid composition.

The crude protein content of the CSR increased significantly from 1.12g/100g in the unfermented cassava starch residues (UFCSR) to 7.02g/100g in the microbially fermented cassava starch residues (MFCSR). The CAP protein increased from an initial 5.30g/100g in the unfermented cassava peels (UFCP) to 10.94g/100g in the microbially fermented cassava peels (MFCP). Similar improvement was also observed in the degradation of the crude fibre component of the wastes whose value was decreased from 19.20g/100g to12.06g/100g in UFCSR and MFCSR and from38.44g/100g to 5.88g/100g in UFCP and MFCP respectively. The low energy values of the unfermented wastes were significantly enhanced though fermentation with an increase from 10.74MJ ME/kg (UFCSR) to 12.96MJ ME/kg (NFCSR) and to 13.26MJ ME/kg (MFCSR) in the three CSR samples and from 9.03MJ ME/kg (UFCP) to 13.24MJ ME/kg (NFCP) and to 14.04MJ ME/kg (MFCP) in the CAP samples.  The amino acid profile of these wastes revealed that fermentation led to a significant improvement of the protein quality of the wastes and more so in the naturally fermented cassava starch residues. It could be concluded that fermentation either naturally or with selected micro-organisms has the potentials of enhancing the nutritive value of cassava tuber wastes thus opening a vista of opportunities by which these wastes could be converted to wealth. The livestock industry as the major stakeholder could therefore benefit by way of reduced cost of animal feeds while the environment would also be relieved of the huge volume of wastes being discharged into it.