STARCH TO LACTIC-ACID IN A CONTINUOUS MEMBRANE BIOREACTOR

Fermentation production of lactic acid directly from starch was studie d in a membrane recycle bioreactor (MRB) using Lactobacillus amylovoru s. With 50 g litre-1 liquefied starch as feed, essentially complete co n version to lactic acid was obtained up to a dilution rate of 0.2 h-1 ; maximum productivity of 25 g litre-1 h was obtained at 0.5 h-1. A hi gher starch concentration in the feed caused lower conversions, result ing in rapid accumulation of unconverted starch in the fermenter. The MRB was operated continuously for 10 days without significant problems . Media components were responsible for fouling the membrane module.