Isolation and characterization of high exopolysaccharide-producing Weissella confusa VP30 from young children’s feces

Abstract

Background Lactic acid bacteria (LAB) are known to have a significant ability to colonize the human intestinal tract and adhere to the surface of intestinal epithelial cells. Among the various lactic acid bacteria, exopolysaccharide (EPS) producing strains are known to provide a variety of health benefits for their hosts (e.g. anti-inflammatory, antioxidant, antitumor and stress tolerant effects). Recently, EPSs and EPS-producing lactic acid cultures have gained interest within the food industry and are playing important roles as biothickeners and texturizing agents due to their hydrocolloidal nature. In this study, 156 lactic acid bacterial strains isolated from fecal samples of healthy young children were screened and evaluated for active EPS-production capability. Results Among the various human origin lactic acid flora isolated, Weissella confusa VP30 showed the highest EPS productivity and its EPS producing properties were characterized under various cultural conditions in this research. To document the safety of W. confusa VP30, antibiotic resistance, hemolytic, and ammonia production properties were evaluated in addition. No significant negative results were observed. The maximum EPS production by W. confusa VP30 was 59.99 ± 0.91 g/l after 48 h of cultivation in media containing 10% sucrose, far exceeding EPS production by other bacterial strains reported elsewhere. Based on gel permeation chromatography (GPC), the molecular weight of EPS produced by W. confusa VP30 was 3.8 × 10 6 Da. Structural analysis of the released EPS fraction by 13 C and 1 H nuclear magnetic resonance (NMR) spectroscopy revealed that W. confusa VP30 can produce dextran with glucose units linked with 96.5% α (1 → 6) glycosidic bonds and 3.5% α (1 → 3) branches. Conclusion The high EPS production capability and safety of W. confusa VP30 justify food industry consideration of this cell strain for further evaluation and potential industrial use.

Genome-Assisted Characterization of Lactobacillus fermentum, Weissella cibaria, and Weissella confusa Strains Isolated from Sorghum as Starters for Sourdough Fermentation

“…Finally, EPS production assessment revealed that all of the W. cibaria and W. confusa strains were able to produce exopolysaccharides starting from sucrose, and W. confusa UC4052 seemed to show the stronger mucoid phenotype among all the producers; indeed, it was the only isolate where EPS production overwhelmed the streaked-out area, making separate streaks hard to see. This is in line with previous studies, which reported W. confusa as a high EPS producer [ 63 ]. In summary, the selected strains were: W. cibaria UC4051 for its amylolytic activity, W. confusa UC4052 for being the major EPS producer, and L. fermentum UC3641 for its gas production and acidification activity.…”

Structure elucidation and in vitro biological evaluation of sulfated exopolysaccharide from LAB Weissella paramesenteroides MN2C2

“…This result confirmed that the present product is a polysaccharide formed of α-and β-anomers of various hexoses and contained acetyl groups from glucosamine also; it had a pyranose ring overlapped with some side groups. This is in agreement with Jin et al (2019) who isolated EPS from W. confusa VP30 and obtained the same peaks using one proton NMR.…”

“…This strain was used for the largescale production of crude EPS. Also, Jin et al (2019) found that Weissella confusa VP30 strain produced the highest amount of EPS compared to other LAB strains which produced < 0.3 g% of EPS on MRS broth.…”

“…Furthermore, Ren et al (2015) used HPLC successfully to separate mixtures of ten monosaccharides produced from Pleurotus abalonus and identified them as 87.9% d-glucose, 1.1% d-ribose, 4.4% d-galactose, 3.4% d-mannose, 1.9% l-rhamnose, and 1.4% d-glucuronic acid. Also, Jin et al (2019) isolated and identified EPS from W. confusa VP30 which consists of dextran with glucose units. The EPS structure and monomer composition are very important because its application is dependent on its structure and it is specific for each strain (Tukenmez et al, 2019).…”

Effects of Selenium- and Zinc-Enriched Lactobacillus plantarum SeZi on Antioxidant Capacities and Gut Microbiome in an ICR Mouse Model

“…The suspension was plated on Lactobacillus Selection (LBS) agar (Difco, Sparks, MD, USA) to isolate Lactobacillus spp. The plates were incubated anaerobically at 37 °C for 48 h [ 26 ]. Three hundreds of morphologically different microbial colonies were collected and cultured for further tests.…”