Sago starch as a low-cost carbon source for exopolysaccharide production by Lactobacillus kefiranofaciens

Abstract

Low-cost sago starch was used as a carbon source for production of the exopolysaccharide kefiran by Lactobacillus kefiranofaciens. A simultaneous saccharification and fermentation process of sago starch for kefiran production was evaluated. Factors affecting the process such as an initial pH, temperature, starch concentration, including a mixture of a-amylase and glucoamylase were determined. The highest kefiran concentration of 0.85 g/l was obtained at the initial pH of 5.5, temperature of 30°C, starch concentration of 4% and mixed-enzymes with activity of 100 U/g-starch. The use of a mixture of aamylase and glucoamylase could enhance the productivity compared to the use of a-amylase alone. The optimal ratio of a-amylase to glucoamylase of 60:40 gave the highest kefiran production rate of 11.83 mg/l/h. This study showed that sago starch could serve as a low-cost substrate for kefiran production.

Bioprocess development for kefiran production by Lactobacillus kefiranofaciens in semi industrial scale bioreactor

“…The maximal kefiran production (0.83 g L −1 ) was obtained at sucrose concentration of 20 g L −1 after 72 h. Further increase in the concentration of sucrose did not highly increase the production of kefiran. These results were in accordance with those obtained by Yeesang et al (2008), where they reported that further increase in reducing sugar concentration above the optimal concentration does not significantly increase kefiran production. This can be explained on the basis that the concentrations of sucrose higher than 20 g L −1 may restrict the ability of cells to uptake sucrose, thus inhibiting the biosynthesis of kefiran.…”

Characterisation of the exopolysaccharide kefiran produced by lactic acid bacteria entrapped within natural kefir grains

“…Although microbial amylases are generally active at ambient temperatures of up to 60 °C (Yeesang et al. 2008), the optimal temperature for the cell growth and kefiran production from lactose by Lactobacillus kefiranofaciens , which is responsible for kefiran production (Yeesang et al. 2008), was the same as found for kefiran production during this study.…”

“…The highest content of kefiran was obtained at the same temperature as the kefir grains growth ( Τ = 30 °C). Although microbial amylases are generally active at ambient temperatures of up to 60 °C (Yeesang et al. 2008), the optimal temperature for the cell growth and kefiran production from lactose by Lactobacillus kefiranofaciens , which is responsible for kefiran production (Yeesang et al.…”

Bioethanol from sea lettuce with the use of crude enzymes derived from waste

“…In earlier studies, concentrations of a-amylase (different from that used in our study) ranging from 0.19 [17] to 1 g/L [18] were used for the production of kefiran and L-lactic acid from starches. The activity of a-amylase solution may reach 160 units/L when a-amylase concentrations as low as 0.19 g/L are used.…”