Mixed culture solid substrate fermentation of Trichoderma reesei with Aspergillus niger on sugar cane bagasse

Trichoderma reesei LM-UC4, the parent strain, and its hypercellulolytic mut ant LM-UC4E1 were co-cultured with Aspergillus niger ATCC 10864 in solid su bstrate fermentation on alkali-treated sugar cane bagasse for cellulolytic enzyme production. Bagasse was supplemented with either soymeal or with amm onium sulfate and urea, and fermented at 80% moisture content and 30 degree s C. Mixed culturing produced better results with the inorganic supplement. The mutant strain was more responsive to mixed culturing than the parent s train when A. niger was the cooperating partner. In a mixed culture of the mutant with inorganic N-source, 10% more biomass, but 63% more cellulase, 8 5% more endoglucanase and 147% more beta-glucosidase was produced than in s ingle culture. Since co-culturing helped enzyme production more than growth , it appeared that synergistic interactions not directly related to growth were responsible for increased enzyme production. Although soymeal suppleme ntation increased biomass production in the same mixed culture by 30%, it d id not increase enzyme production. Mixed culturing is thus beneficial for t he economic production of cellulases on nutritionally poor agricultural res idues, without the need for supplementation with expensive organic suppleme nts. (C) 1998 Elsevier Science Ltd. All rights reserved.