Fermentation characteristics of vinegar residue and some natural materials

Solid state fermentation is an attractive process to produce cellulase economically due to its lower financial investment and lower operating costs. Generally available natural materials in our study included vinegar residue, wheat bran, rice bran and wheat straw. Cellulase production was carried out by solid state fermentation using these materials as the substrate of Trichoderma koningii. The ingredients of natural materials, associated with the effects of water content, time and nitrogen sources on cellulase synthesis were studied. A comparatively high cellulase activity (>4 IU·g–1 SDM) was obtained in the fermentation batch. The optimum culture time of vinegar residue, wheat bran and wheat straw were 72 hours, but that of rice bran was 60 hours. Total water contents of wheat bran, rice bran and wheat straw should not exceed 50% and that of vinegar residue should not be more than 60%. It was also shown that nitrogen salts contributed much to fermentation. (NH4)3PO4 and urea achieved good results in promoting enzyme activity.