Preparation of Microcapsules Containing Extractants and the Application of the Microcapsules to the Extractive Fermentation of Lactic Acid

Abstract

The extraction of lactic acid from an aqueous solution by microcapsules containing extractants was investigated in order to prevent the dissolution of the extractants in the aqueous solution. Microcapsules containing tri-n-octyl phosphine oxide (TOPO) and a mixture of tri-n-butyl phosphate (TBP) and tri-n-octylamine (TOA) showed high extractability at low pH, but low extractability at the optimum pH of the fermentation. Then, toxicity of these microcapsules to immobilized Lactobacillus rhamnosus was investigated. The microcapsules containing TOA-TBP showed high toxicity to the cells, on the other hand, the microcapsules containing TOPO slightly affected lactate production. The microcapsules containing TOPO were used in the extractive fermentation process by reasons of their lower toxicity to the microbes than those containing TOA-TBP. The extractive fermentation of lactic acid coupled with a column packed with the microcapsules was found to be very effective method from the point of view of cell growth.