Isolation of Lactic Acid Bacteria Producing Mannitol from Indonesian Cocoa Beans Fermentation

Abstract

Mannitol is a polyol that is widely used in many industries. Lactic acid bacteria are known as one of the microorganisms which produce mannitol in certain conditions. LABs are widely found in fermentation products. This research aims to isolate LAB-producing mannitol from Indonesian cocoa bean fermentation as an alternative to commercial mannitol production. LAB isolated from 0 to 96 h of fermentation, screened by the clear zone formed in MRS medium contained CaCO₃ 1% and its catalase activity. Initial screening of 94 LAB isolates using TLC yielded only ten LAB-producing mannitol isolates. Further screening through HPLC analysis showed that LAB 4.32 produced the highest concentration of mannitol (1.873 g/L). Analysis of 16S rRNA genes revealed that LAB 4.32 was Lactobacillus plantarum. Cultivation of the LAB 4.32 in tofu whey with the addition of (NH₄)₂SO₄ 1% (w/v) and fructose 5% (w/v) obtained the highest mannitol production up to 0.719 g/l.