Bioprocessing of Anogeissus leiocarpus Sawdust for Optimum Production of Total Soluble Protein by Aspergillus niger and Trichoderma harzianum

Abstract

Sawdust of different types adorns our cities' landscape as lignocellulosic wastes of the wood industry; whose disposal often involves burning a process that pollutes the atmosphere. The availability of sawdust as an alternative substrate and the wood-degrading ability of fungi make it cost-effective for the bioproduction of value-added products of industrial importance. In this study, fungi isolated from sawdust were morphologically identified. Anogeissus leiocarpus sawdust moistened with cellulase medium was thermally processed for 1 h. Duplicate flasks were optimized by varying environmental factors to produce Total Soluble Protein (TSP) in Solid State Bioprocessing (SSB). Flasks content was adjusted (pH 4.0 - 7.0), inoculated solely with two agar plugs (6 mm cork borer) of 5-day-old cultures of Aspergillus niger and Trichoderma harzianum, and incubated (28^oC - 40^oC) for 6 - 14 days. All TSPs produced were statistically different (p < 0.05). The TSP produced by A. niger and T. harzianum ranged from 157-365 mg/L and 175-362 mg/L, respectively, with both optima at pH 5.0. However, TSP production by A. niger and T. harzianum ranged from 103-350 mg/L and 181-885 mg/L with optima at 35^oC and 28^oC, respectively. Both fungi produced the highest TSP on day 10 of incubation. The study established that A. niger and T. harzianum could be useful tools for the efficient bio-processing of sawdust into TSP for industrial and biotechnological applications.