Improved lactic acid productivity by simultaneous recovery during fermentation using resin exchanger

Lactic acid is a versatile organic acid that can be used in various applications. One of the promising applications of lactic acid is in bioplastic industry. Lactic acid is used as  the monomer building block in polylactic acid synthesis. Unlike the existing applications in food and pharmaceutical industries in which lactic acid is used as the additive, it becomes the major raw material in polylactic acid production. This, therefore, raises the demand of  lactic acid and eventually increases the market price. In order to expedite the bioplastic industry, cost competitiveness to the existing plastic is a big concern. The cost effectiveness and process robustness are the key success factors in bioplastic industry. Currently, lactic  acid is produced via bacterial fermentation using the lime-based process. After fermentation, lactic acid was recovered from the fermentation broth by various techniques including solvent extraction, reactive distillation, ion exchanger, and electrodialysis. To achieve low  production cost, not only high fermentation rate is necessary, effective recovery process is also required. In this study, we attempted simultaneous recovery of lactic acid coupled with fermentation to drive the productivity and long-term operation in continuous culture. Anion exchange resin, Amberlite IRA-400, was selected for recovering lactic acid from the bacterial culture. The preliminary results in batch adsorption showed that among other resins studied, Amberlite IRA-400 provided the best separation efficiency. Further study on fixed bed adsorption and simultaneous fermentation and lactic acid recovery using this resin were conducted and the results will be discussed in this presentation.