Exopolysaccharides (EPS) from Lactiplantibacillus plantarum have been found to possess a variety of biological activities such as antitumor and antioxidant, but few studies on the synthesis of EPS by L. plantarum in skim milk have been reported. The aim of the present study was to screen L. plantarum with high EPS production capability in skim milk, which will be great significance to the application of L. plantarum in dairy products. L. plantarum RT-6 (CGMCC No. 26778), with a high capability of producing EPS, was isolated from homemade yogurt collected in Guilin, Guangxi, China by the colony thread-drawing method. Its EPS producing capability was compared with that of other L. plantarum strains. The culture conditions for EPS production by L. plantarum RT-6 were optimized using one-factor-at-a-time (OFAT) method and response surface methodology (RSM). It was found that among all tested L. plantarum strains, RT-6 exhibited the highest EPS yield when cultured in reconstituted skim milk, whereas most other strains grew slowly or even could not grow. The optimal culture conditions were determined as 39 h, 32 ℃, 101 mg/mL and 1.488 mmol/L for fermentation time, fermentation temperature, skim milk concentration and concentration of mixed essential amino acids, respectively. Under the optimized conditions, the yield of EPS was 241.1 mg/L, 2.6 times higher than that before optimization.

Paenibacillus bovis BD3526 was cultured in a medium containing 20 g/L glucose, 20 g/L starch, 20 g/L ammonium sulphate, 10 g/L yeast extract, 2.6 g/L dipotassium hydrogen phosphate, 0.5 g/L MgSO4·7H2O and 0.25 g/L NaCl for 48 hours to produce antimicrobial substances with good thermal stability, acid and alkali resistance. The results of protease treatment showed that the fermentation supernatant contained antimicrobial peptides. It had strong antimicrobial activity against Gram-positive bacteria, but not against Gram-negative bacteria. At least two antibacterial substances were isolated by Sephadex LH-20 gel column chromatography from the fermentation supernatant, but not from wheat bran fermented with Paenibacillus bovis BD3526.

Lactobacillus plantarum is a ubiquitous microorganism, and as a member of the probiotic family it owns various probiotic functions including regulating the balance of the intestinal flora, maintaining normal immune response and lowering cholesterol levels, and has a broad application in the food industry. This article aims to review the mechanism underlying the health benefits of typical strains of Lactobacillus plantarum and to assess the factors limiting the application of Lactobacillus plantarum in the dairy industry.The commonly used solutions are presented.Hopefully,this review will provide a useful basis for practical application of Lactobacillus plantarum.

Based on their distinctive colonial morphology when co-cultured in MRS agar containing different carbon sources, two selective enumeration methods, namely difference method and chromatic aberration method, were established for Lactobacillus plantarum ST-Ⅲ and Leuconostoc mesenteroides BD1710 in co-culture. The reliability of these two methods could meet the requirements for selective counting of individual strains. The difference method was more suitable for research with high precision requirement owing to its higher average detection rate (97.2％ vs 95.4％ for ST-Ⅲ, 96.4％ vs 94.0％ for BD1710) compared with the chromatic aberration method, whilst the chromatic aberration method was superior in operability and cost and could provide factories with a fast way to determine viable bacterial counts in related products.

In recent years,exopolysaccharides produced by food-grade bacteria has aroused great interest.worldwide.In addition to the biological effects on their producers themselves,bacterial exopolysaccharides are widely applied in the agricultural,food,pharmaceutic as well as chemical industries for their prominently biological activities and processing properties.In this paper,the roles of some bacterial exopolysaccharides in biofilm formation and their chemical structures and prospects for application are reviewed.Further investigation on bacterial exopolysaccharides is also suggested.

Researchers have been making significant efforts to reveal the relationships between the gut microbiota and diabetes mellitus. As a special bacterial population in the intestinal tract, probiotics have unique advantages in delaying and controlling the occurrence of diabetes. In this article, the mechanisms of action and superiorities of probiotics in the prevention and control of diabetes are reviewed and some future development trends are also predicted.

The growth promoting effect of the supernatant of fermented skim milk with Paenibacillus spp. BD3526 on Lactobacillus plantarum ST-Ⅲ inoculated into skim milk was analyzed in this study. The results showed that the supernatant of BD3526 cultured in skim milk for 5–9 d significantly promoted the growth of ST-Ⅲ in skim milk and exhibited high milkclotting activity. After ST-Ⅲ was cultured in skim milk added with the supernatant of BD3526 for 24 h, the pH value decreased from 6.44 to 4.70–5.08, and milk clotting was observed at 16 h along with a viable cell count of 9.22–9.35(lg(CFU/mL)).

Leuconostoc mesenteroides consists of four subspecies, L. mesenteroides subsp. mesenteroides, L. mesenteroides subsp. dextranicum, L. mesenteroides subsp. suionicum and L. mesenteroides subsp. cremoris. Among these subspecies, only L. mesenteroides subsp. mesenteroide is currently listed for use as a food additive by China’ Ministry of Health and the FDA. The subspecies of L. mesenteroides subsp. mesenteroide cannot be identified simply by 16S rRNA gene sequencing. Therefore, the present study investigated subspecies identification of L. mesenteroides BD1710 using the established primers based on 16S–23S rRNA gene intergenic spacer region sequence similarity and three specific housekeeping genes. The results confirmed the strain to belong to L. mesenteroides subsp. mesenteroides.

Milk fermented by Leuconostoc mesenteroides Leuco4 or yoghurt starter culture YO-MIX465 (consisting of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus) and their mixture at a mass ratio of 1:4 were evaluated for viscosity, syneresis, texture properties and sensory quality. Compared with YO-MIX465-fermented milk, fermented milk containing Leuconostoc mesenteroides Leuco4 had better water-holding capacity and viscosity and desired viscosity, taste and stability and could meet the requirement of clean-label products due to not containing any food additives.