Abstract

The potentially hypocholesterolemic strain, designated PL02, of Lactobacillus plantarum, was isolated from infant feces. The aim of this study was to characterize and to cultivate this isolate for biomass production in a 5 L fermentor by batch or fed-batch fermentation. A modified medium composition without peptone was used to produce more viable cells with a 150 rpm agitation speed and 0.5 vvm of aeration during incubation. A cell concentration of 2.2 g dry cell weight (DCW) per liter in fermented broth was reached in a 5 L fermentor after the glucose was consumed completely during batch fermentation. In addition, biomass was significantly improved at 28 h of fed-batch fermentation (9.45 g DCW/l) over a constant feeding rate of 20 ml/h of feeding solution since the glucose was consumed at batch process. A much shorter fermentation time (15 h) and greater biomass (10.12 g DCW/l) was obtained by using multistep feeding rates to maintain glucose concentration of 1 to 5 g/l during fed-batch process. The biomass of L. plantarum PL02 produced by fed-batch fermentation was greater than that achieved by batch fermentation and the fed-batch method might also be suitable for other lactic acid bacteria fermentation.

Key words: Lactobacillus plantarum, fermentation, fed-batch fermentation, cholesterol