Immobilization of Lactobacillus helveticus on a spiral-sheet bioreactor for the continuous production of lactic acid

The objective of this work was to determine the ability of immobilized Lactobacillus (L.) helveticus on spiral-sheet bioreactor system for the continuous production of lactic acid. In this technology, active culture of L. helveticus (ATCC 15009) was inoculated into 9 liters of fresh MRS and incubated at 37°C for 18 h. Fermented broth was transferred into the spiral-sheet bioreactor and allowed to immobilize for 24 h. After successful immobilization, MRS broth was withdrawn and replaced by fresh 4.8% lactose-MRS broth or whey base medium under aseptic conditions. Bioreactor was connected to temperature and pH control Bioflo III fermentor. Samples were withdrawn at different time intervals and analyzed for lactose and lactic acid contents and for pH values. Results indicated that lactic acid yield was 0.59 g g^-1 and 0.92 g g^-1 in lactose-MRS broth and whey base medium, respectively. Our result showed that immobilization of L. helveticus on spiral-sheet reactor was successful for the continuous production of lactic acid using laboratory broth or whey.