Short communicationHigh-density culture of Lactobacillus plantarum coupled with a lactic acid removal system with anion-exchange resins

•We model the relationship between the specific growth rate and osmotic pressure.•A lactic acid removal system to realize high density cultivation is designed.•The anion-exchange resins used must be converted to OH− form.•The culture system is effective in increasing the biomass of lactic acid bacteria.

A fed-batch culture of Lactobacillus plantarum was coupled with a lactic acid removal system to achieve high-density cultivation. Different types of anion-exchange resins were evaluated to establish the lactic acid removal system. This system comprised a cell bioreactor fitted with two anion-exchange columns: one for adding anion-exchange resins, converted to the OH− form, to the bioreactor and the other for filtering the resins after adsorption of acid anions. The pH of the culture broth was controlled at between 6.5 and 7.0 by adding anion-exchange resins to remove lactate. In addition, the growth kinetics in the fed-batch and pH-controlled culture were investigated. The well-known Monod equation was modified to describe the relationship between the specific growth rate and the osmotic pressure. In this cultivation system, a cell concentration of 34.5 g L−1 was obtained after 12 h, being about 13.3 and 2.3 times higher respectively than that of a batch culture and a fed-batch and pH-controlled culture without the addition of resins. The proposed culture system was effective in increasing the biomass of lactic acid bacteria.

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