Statistical Optimization of Lactic Acid Extraction from Fermentation Broth Using Emulsion Liquid Membrane

Abstract

The performance of emulsion liquid membrane (ELM) for lactic acid extraction from fermentation broth was investigated. Fermentation broth containing lactic acid (LA) was obtained from the fermentation of sugarcane molasses using corn steep liquor (CSL) as nitrogen source by immobilized Lactobacillus casei MTCC 1423 cells after 60 h of incubation time. Lactic acid extraction using ELM from fermentation broth was investigated. Extraction efficiency, η ext (82 %) after 13.5 min of the batch extraction time was obtained and also observed that the stability of the emulsion was affected in the presence fermentation broth constituents. Keeping in view the stability aspect of emulsion liquid membrane for in situ lactic acid extraction during fermentation, process optimization of the process variables for maximizing the lactic acid extraction from fermentation broth using response surface methodology was carried out. Central composite rotatable design (CCRD) for three variables viz., span 80 concentration, c s ; TOA concentration, ψ; batch extraction time, τ at five levels for lactic acid extraction from fermentation broth has been employed. A numerical optimization technique was applied to find the optimum conditions for maximizing the extraction of lactic acid from fermentation broth and the optimum conditions obtained for maximum lactic acid extraction efficiency, η ext (82.67 %) were: span 80 concentration, c s : 5 % (v/v); TOA concentration, ψ: 9.5 % (v/v); batch extraction time τ: 28 min. The results suggest that the ELM has significant potential for in situ lactic acid extraction.