文摘
Hexanoic acid production by a bacterium using sucrose as an economic carbon source was studied under conditions in which hexanoic acid was continuously extracted by liquidiquid extraction. Megasphaera elsdenii NCIMB 702410, selected from five M. elsdenii strains, produced 4.69gl1 hexanoic acid in a basal medium containing sucrose. Production increased to 8.19gl1 when the medium was supplemented by 5gl1 sodium butyrate. A biphasic liquidiquid extraction system with 10% (v/v) alamine 336 in oleyl alcohol as a solvent was evaluated in a continuous stirred-tank reactor held at pH6. Over 90% (w/w) of the hexanoic acid in a 0.5 M aqueous solution was transferred to the extraction solvent within 10h. Cell growth was not significantly inhibited by direct contact of the fermentation broth with the extraction solvent. The system produced 28.42gl1 of hexanoic acid from 54.85gl1 of sucrose during 144h of culture, and 26.52 and 1.90gl1 of hexanoic acid was accumulated in the extraction solvent and the aqueous fermentation broth, respectively. The productivity and yield of hexanoic acid were 0.20gl1h1 and 0.50gg1 sucrose, respectively.