USING MICROBIAL CULTURES FOR PRODUCING ANIMAL FEEDS FROM AGRICULTURAL WASTES

Abstract

Large amounts of agricultural wastes reaching hundreds of millions of tons are produced annually in cultivated land. Most of these organic materials are of no or very low economic value, farmers usually get rid of them by burning which results in serious environmental pollution. The objective of the present work is to study possible use of some agricultural wastes namely, sugar-cane bagasse, com stalks and cotton stalks as carbonaceous materials for obtaining valuable products. Bioconversion of these materials under laboratory and field conditions using selected strains of microorganisms (solid state fermentation technique) together with some chemical treatments was carried out in a sequence of experiments. Evaluation of the final products was made. Solid state fermentation (SSF) of sugar-cane bagasse by mixed culture (Trichoderma viride EMCC 107, Saccharomyces cerevisiae EMCC 56 and Cellulomonas cellulans ATCC 21681), succeeded to increase the crude protein content of the fermented sugar-cane bagasse up to 7.07 % at moisture content 80 %. Also, the biological treatment succeeded to decrease the organic carbon content from 37.20 (raw material) to 27.20 % after 23 days of solid state fermentation at 80 % moisture content. Solid state fermentation of com stalks by mixed culture increased markedly crude protein up to 12.25% after 1 week. Moreover solid state fermentation of cotton stalks (ground to 100 mm and 50 mm particle size followed by heat treatment either by autoclaving or steaming) recorded that grinding to 100 mm particle size resulted in less crude protein production (9.28 % and 9.80 % in autoclaving and steaming, respectively) than in case of cotton stalks ground to 50 mm particle size (10.20 and 11.53 % crude protein production m both autoclaving and steaming, respectively). Combination of chemical (urea 5 %) and biological treatment (solid state fermentation) of cotton stalks was applied in both laboratory scale and in situ field. It could be stated that, treatment with urea applied in situ field revealed crude protein increase up to 8.33 %followed by increasing