Production of enzymes from potato pulp using batch operation of a bioreactor

Trichoderma reesei strains MCG77 and Rut C30 were cultivated in batch operation in a stirred tank reactor on potato pulp (PP) consisting of starch, pectin, cellulose, and hemicellulose; potato pulp residue (PR) without starch and pectin; or enzymatic residue (ER), respectively, as substrate and potato protein liquor (PPL) as supplement. The enzyme mixtures produced by the fungi were characterized by four assays: with avicelase, CMCase, xylanase, and FP-activities. Trichoderma reesei Rut C30 yielded higher activities than Trichoderma reesei MCG77. The enzyme activities and productivities obtained with PR are comparable to those obtained by other groups using pure cellulose and a synthetic nutrient solution in batch culture. An optimal operation strategy was derived to obtain maximum enzyme activity and productivity. After converting PR with the enzymes produced and using the residue, ER, as substrate for enzyme production, 85% (w/w) of the pulp was utilized.