In situ combination of fermentation and electrodialysis with bipolar membranes for the production of lactic acid: Operational compatibility and uniformity

An in situ combination of fermentation and electrodialysis with bipolar membranes was customized for the production of lactic acid to achieve their operational compatibility and uniformity. Primarily, fermentation experiments for lactic acid production were conducted by Lactobacillus plantarum with an average lactate productivity of 1.76 g/(L h) and yield coefficient of 56.77%. Subsequently, an electrodialysis with bipolar membranes (EDBMs) stack was established with the fermented lactate mixtures as a feed. Effect of operating current density on the production of lactic acid and alkali liquor was investigated. Results indicated that only the current density of no less than 50 mA/cm2 can produce enough alkali liquor to meet the need for fermentation. Ultimately, a combination of fermentation and EDBM process was carried out and the integration can achieve a lactic acid recovery ratio of 86.05% at the current density 60 mA/cm2.