Lactic Acid Production Using Sugarcane Juice as an Alternative Substrate and Purification through Ion-Exchange Resins

Abstract

The commercial importance of lactic acid (LA) is due to its versatility, especially in the food industry, and for being the precursor of poly-lactic acid, which demands a high-quality LA precursor. The overall LA production process still has some bottlenecks related to costs; thus, alternative substrates such as sugarcane juice may reduce the cost of the fermentation medium and provide a favorable environment for the Lactobacillus pentosus strain, which continues to be explored. In this context, this work presents the process of producing LA from sugarcane juice. The LA purification method is also described using different ion-exchange resins, both in packed columns and in a stirred tank. The fermentation kinetics showed the highest LA production of 113.74 g/L in 96 h, in which a productivity of 1.18 g LA/L∙h was reached. Among the purification techniques, the combined use of Amberlite IR120 and IRA-67 resins under agitation in a stirred tank was the best condition, and resulted in a final LA concentration of 189.11 g/L after 120 min, with 95% LA mass recovery. This result demonstrates a simplified way to use ion-exchange resins safely and in a controlled environment, and with process scale-up viability.