Efficient magnesium lactate production with in situ product removal by crystallization

• The ISPR process is based upon magnesium lactate crystallization.
• No external seed crystals are needed in crystallization.
• The crystallization is conducted at 42 °C without cooling and re-heating.
• Using ISPR fermentation saves 40% water, 41% inorganic salts and 43% yeast extract.

In this paper, attempts were made to develop an in situ product removal process for magnesium lactate production based on crystallization. The crystallization was conducted at 42 °C without seed crystal addition. The product concentration, productivity and yield of fermentation coupled with in situ product removal (ISPR) reached 143 g L−1, 2.41 g L−1 h−1 and 94.3%. In four cycles of crystallization, the average reuse rate of fermentation medium and removal rate of product reached 64.0% and 77.7%. At the same time, ISPR fermentation saved 40% water, 41% inorganic salts and 43% yeast extract (YE) as compared to fed-batch fermentation. The process introduces an effective way to reduce the amount of waste water and the raw material cost in magnesium lactate fermentation.