Exopolysaccharide production by lactobacillus confusus TISTR 1498 using coconut water as an alternative carbon source: The effect of peptone, yeast extract and beef extract

Abstract

Coconut water (CW) is a by-product of food industry and has little value in Thailand. It is usually discarded as a waste into the environment. Consequently, we developed a value added process of exopolysaccharide (EPS) production using Lactobacillus confusus TISTR 1498 and coconut water. The effect of three expensive supplements (peptone, yeast extract and beef extract) on EPS and biomass production was investigated at 35°C for 24 h. Using a mod-MRS-CW medium, prepared by replacing the de-ionized water with 100% CW and supplemented with 20 g/l crystalline sucrose and a reduced quantity (50%) of the three expensive supplements (5 g/l of peptone, 2.5 g/l of yeast extract, and 2.5 g/l of beef extract) gave the highest yield of EPS (12.3 g/l). By optimizing the conditions for fermentation (pH 5.5, agitation speed at 50 rpm and initial sucrose concentration of 100 g/l), EPS yield increased up to 38.2 g/l. When compared with the modified MRS medium, the medium supplemented with CW was found to be suitable for the reduction of cost spent on the organic nitrogen and growth factors (savings close to 50%).