PROFILE OF HYDROLASES ACTING ON MAJOR MACROMOLECULES OF TOMATO PROCESSING WASTE DURING ANAEROBIC-DIGESTION

The progression of anaerobic digestion of tomato processing waste was studied in relation to the appearance in the slurry of the hydrolytic enzymes, cellulases (carboxymethyl cellulase, filter paper cellulase, and beta-glucosidase), xylanase, amylase, pectinase (polygalacturonase), protease (acid and neutral proteases), and lipase. In the batch process lasting 110 days, lipase and xylanase were the early enzymes to show high activities, followed by filter paper cellulase, carboxymethyl cellulase, proteases, and beta-glucosidase. In the semicontinuous process, the levels of carboxymethyl cellulase, beta-glucosidase, and xylanase activities were highest after 8 days of hydraulic retention time (HRT), whereas the filter paper cellulase, pectinase, and lipase activities were highest after 32 days HRT. The pH and temperature optima of the enzymes were found to be different from the conditions prevailing in the digesters.