ABSTRACT

Cassava bagasse is a fibrous residue obtained from the tapioca starch factories, which contains high starch and cellulose. In addition, it comprises some valuable components like proteins, pectin, lignin, fat, ash, and minerals. Therefore, cassava bagasse is considered as a rich substance to produce microbial products by semi-solid fermentation using rotating-drum bioreactor system. Such technique was designed and made in our study in the laboratory conditions.This equipment helps towards to have a microbial products of high value in industrial scale. Trichoderma viride VTCC-F-754, having many advantages to fermentation procedure [e.g., rapidly develop (approximately 9cm agar after 3 days of culture), highly degrade cellulose and starch under starch and CMC culture (2cm and 1.07 cm diameter after 5 days, respectively)] were used in this work.The growth curves of T. viride were measured and the spores were admitted on day 3 at 1.18x10⁸ (spore/ml). The laboratory experimental planning was conducted according to the optimal parameters obtained in each element through software Statgraphics Centurion XV. The results showed that the spore density ofT. virideVTCC-F-754 strains obtained 2.69 x 10⁹ (spore/g) under optimal culture conditions [i.e., 60.9% moisture, 5.34pH, rate strains: 1. 14% (x10⁸, v/w), (NH₄)SO₄: 0.57%, and KH₂PO₄: 0.15%]. Survival rates of microbes after drying and time maintenanceare important factors to evaluate the quality and cost of products.

Key word:Trichoderma viride,cassava bagasse, rotating-drum bioreactor and microbial products.