Optimization of Exopolysaccharides Production by Lactiplantibacillus pentosus B8 Isolated from Sichuan PAOCAI and Its Functional Properties

Exopolysaccharides (EPS)-producing strain B8 isolated from Sichuan paocai was identified as Lactiplantibacillus pentosus. The complete genome of L. pentosus B8 was sequenced with 329x coverage and a total size of 3772175 bp. Genome analysis identified 7 biosynthetic gene clusters relevant to EPS production. The culture conditions for EPS production (EPS-B8) were optimized by single factor trials and response surface methodology (RSM). Sucrose at 4% concentration, beef extract and soybean peptone combination at 1% concentration, initial pH of 6.28, fermentation time of 35.7 h, and inoculation amount 3.8% were found optimal conditions leading to the EPS-B8 production of 1401.5 +/- 9.5 mg/L, approximately 1.4-fold higher than that under the initial non-optimized conditions. TLC analysis revealed mannose, glucose and galactose as the components of EPS-B8. Solubility, water holding capacity, and oil holding capacity of EPS were 95.1 +/- 1.4, 20.3 +/- 0.6, and 965.5 +/- 12.3%, respectively. EPS-B8 also exhibited high emulsifying activity against various edible oils. EPS-B8 efficiently coagulated sucrose-supplemented milk in a concentration-dependent manner. Besides, the treatment of rice seeds with EPS-B8 solution increased the length of shoots and roots. Our study provides evidence supporting the use of EPS-B8 as a functional food ingredient and plant-growth regulator.

Automated summary

Lactiplantibacillus pentosus strain B8 isolated from Sichuan paocai was found to produce high levels of exopolysaccharides (EPS-B8) with desirable properties such as solubility, water holding capacity, oil holding capacity, emulsifying activity, and coagulating ability. EPS-B8 also demonstrated the ability to enhance the growth of rice seedlings. These findings suggest the potential use of EPS-B8 as a functional food ingredient and plant-growth regulator.