REVIEW OF EXTRACTION TECHNOLOGIES FOR ORGANIC ACID PRODUCTION

DUE to increasing environmental concern, the replacement of petrochemicals with renewable chemicals such as organic acids is attracting significant research interest and investment all over the world. Organic acids have wide-ranging applications depending on their structures, and can be utilised in the manufacture of plastics, textiles, resins, food products, etc. The income stream of the sugar industry will be increased if organic acids are economically produced from bagasse and sugar process streams. Organic acids can be produced by nonfermentative and fermentative routes. The non-fermentative approach involves the direct extraction of organic acids such as aconitic acid from sugar processing. Fermentative processes use selected yeast and/or bacterial strains on sugar process streams and bagasse to produce organic acids (e.g., acetic acid, lactic acid and succinic acid). The main disadvantage of using sugar process streams and bagasse (or other biomass) to produce organic acids is that low concentrations of these compounds are present in the solution matrix. As a consequence, technologies that underpin the economic recovery of these organic acids from dilute solutions are currently being targeted by biotechnological organisations. This paper discusses the potential for organic acid production from sugarcane process streams and bagasse, and reports on the status of technologies such as precipitation, solvent extraction, electrodialysis and supercritical fluid extraction to extract organic acids from complex media.