Extractive fermentation of l-(+)-lactic acid by Pediococcus pentosaceus using electrodeionization (EDI) technique

In this work, extractive fermentation of l-(+)-lactic acid (lactate) was carried out using an electrodeionization (EDI) technique. Pediococcus pentosaceus was used as the biocatalyst because of its homo-fermentative characteristic. The effect of initial lactate concentrations on microbial growth was initially investigated. A mathematical simulation of the product inhibition was successfully illustrated. It was found that the critical lactate concentration was approximately 80 g/L. Various operating conditions were investigated to assess the EDI performance. The system was subsequently applied for in situ removal of lactate from the fermentation broth. The specific deactivation constant (kd) was substantially reduced from 0.026 h−1 to 0.0054 h−1 resulting in a much improved half life of the biocatalyst. The highest lactate concentration in the receiving solution was 185 g/L.

► EDI technique promotes lactic acid production yield.
► The in situ lactate removal results in reduction of deactivaton constant.
► This membrane bioreactor system significantly reduced impurities.