In situ reactive extraction of lactic acid from fermentation media

Extractive lactic acid fermentation was investigated in the presence of sun flower oil and Alamine-336 (with oleyl alcohol as the diluent solvent). Lac tic acid was produced in various media at 37 degreesC using Lactobacillus d elbrueckii (NRRL-B 445). First, the effects of oleyl alcohol (33.3%, v/v), immobilisation, and immobilisation in the presence of sunflower oil (5, 10, 15%, v/v) on lactic acid production were investigated. It was found that o leyl alcohol did not affect production while addition of sunflower oil incr eased lactic acid production from 10.22 to 16.46 gdm(-3). On the other hand , a toxic effect was observed for oleyl alcohol solutions containing 15-50% (v/v) Alamine-336. A maximum total lactic acid concentration of 25.59 gdm( -3) was obtained when an oleyl alcohol solution containing 15% (v/v) Alamin e together with immobilised cells with 15% (v/v) sunflower oil was used. Th is value was about 2.5 times that obtained from fermentation without organi c solutions. (C) 2001 Society of Chemical Industry.