DOWNSTREAM PROCESSING OF LACTIC-ACID BY MEMBRANE-BASED SOLVENT-EXTRACTION

Lactic acid has extensive use in the food and chemical industry, About half the lactic acid used in the world is produced by fermentation of carbohydrates using lactic acid bacteria. The recovery of lactic acid from the fermentation broth is more difficult than the fermentation i tself. In the present work a study of membrane-based solvent extractio n as a separation unit for the continuous downstream processing of lac tic acid from fermentation broth was carried out. The experiments were performed using simulated fermentation broths made of lactic acid in acetate buffer or distilled water as the feed solution. The effects of membrane material, organic carrier, and pH of the feed solution on me mbrane extraction efficiency were investigated. A separation degree of 35% was obtained by using a polyetheretherketone (PEEK-WC 14%) membra ne with 5% trioctylamine as the organic carrier in n-heptane. The expe rimental results obtained with the simulated system encourage the use of membrane-based solvent extraction with a real fermentation broth.