Fermentative Conversion of Cellulose to Acetic Acid and Cellulolytic Enzyme Production by a Bacterial Mixed Culture Obtained from Sewage Sludge

A simple procedure that uses a cellulose-enriched culture started from sewage sludge was developed for producing cellulolytic enzymes and converting cellulose to acetic acid rather than CH(4) and CO(2). In this procedure, the culture which converts cellulose to CH(4) and CO(2) was mixed with a synthetic medium and cellulose and heated to 80 degrees C for 15 min before incubation. The end products formed were acetic acid, propionic acid, CO(2), and traces of ethanol and H(2). Supernatants from 6- to 10-day-old cultures contained 16 to 36 mM acetic acid. Cellulolytic enzymes in the supernatant were stable at 2 degrees C under aerobic conditions for up to 4 weeks and had the ability to hydrolyze carboxymethyl cellulose, a microcystalline cellulose, cellobiose, xylan, and filter paper to reducing sugars.