OPTIMIZATION OF INOCULUM SIZE AND INCUBATION PERIOD OF SOLID STATE FERMENTED CASSAVA RESIDUAL PULP

Abstract

A fourteen day study was carried out to determine the optimum initial inoculum level and incubation period of a solid state fermentation (SSF) process using filamentous fungus, Aspergillus niger (USMF 4) and cassava residual pulp (CRP) as the microorganism and substrate respectively. The study comprised four sets of experiments at room temperature; set A (un-inoculated) serving as control; and three levels of initial inoculum: B (5.55x 10° spore forming units/ml, sfu/ml), C (1.11 x 10° sfu/ml) and D (1.65 x 10° sfu/mi.). Each set had eight samples in conical flasks; at every 48hours, a flask was removed from each set for analysis. It was observed that SSF was positively affected by the inoculum level and the incubation period. Generally, better values in the parameters (pH 6.12, 83.50% dry matter and 6.23% crude protein) analyzed were obtained in treatment C (1.1110 sfu/ml.) and at incubation period of 12 days for cassava residual pulp (CRP). The results of this study indicated that Aspergillus niger(USMF 4)performs best at I.11x1 O9 sfu/ml inoculum level for the improvement of the nutrient values of agro industrial by products; with optimal increment of the crude protein content of cassava residual pulp (CRP) at 12th day of solid state fermentation (SSE).