Monday, July 27, 2009
P62

ISOLATION OF HEXANOIC ACID PRODUCING CLOSTRIDIUM BS-1 USING GALACTITOL

Byung-Seung Jeon, Byung-Chun Kim, Seil Kim, Youngsoon Um, and Byoung-In Sang. Center for Environmental Technology Research, Korea Institute of Science and Technology, 39-1 Hawolgok, Sungbuk, Seoul, 136-791, South Korea

Hydrogen, methane, ethanol, and butanol, which can be used as bio-energy resources, could be produced from fermentation. In addition to such well known fermentation products, hexanoic acid can be produced from fermentation and offer advantages as a bio-energy resource because of its high energy density (6 carbons) and low water solubility (11 g l-1, 20°C) if the hexanoic acid could be converted to hexanol through the catalytic hydrogenation. In this study, a hexanoic acid producing bacterum using galactitol as substrate was isolated from activated sludge. The sludge was heated at 100°C for 30 minutes to suppress the non-spore forming methanogens, and then used as inoculums. The growth of other bacteria was inhibited using nitrogen limited modified CAB. The isolate was designated as Clostridium BS-1. The strain was maintained routinely using RCM with galactitol. The major fermentation products of the strain were butyric acid, and hexanoic acid. The production of butyric acid and hexanoic acid was about 2±0.3 g l-1 and 4±0.5 g l-1, respectively. The yield of produced hexanoic acid was about 0.35±0.1 g/ galactitol g. Using prolin as an osmo-protector, the production of hexanoic acid was increased to 6±0.5 g l-1.