Structural characterization and hepatoprotective activity of exopolysaccharide from Bacillus velezensis SN-1.

BACKGROUND: Exopolysaccharide biopolymers produced by microorganisms are crucial to the environment. They contribute to areas such as the health and bionanotechnology sectors, food and cosmetic industries as gelling agents, and environmental sector as flocculants owing to their biodegradability and non-toxic nature. The current study aimed to isolate the fraction of released exopolysaccharide (rEPS) by Bacillus velezensis SN-1 from Chinese Da-Jiang. RESULTS: The weighted average molecular weight of the major isolated component, rEPS-2, was 202 kDa, and its monosaccharide composition included mannose, glucose, and galactose at a molar ratio of 0.38:0.30:0.32. Further, the rEPS-2 was characterized using methylation analysis and one-dimensional/two-dimensional nuclear magnetic resonance (1D/2D NMR) spectroscopy. In vivo hepatoprotective effects indicated that rEPS-2 could alleviate carbon tetrachloride (CCl4 )-induced liver injury in mice by lowering the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and the malondialdehyde (MDA) levels. Furthermore, rEPS-2 can increase the expression of antioxidant genes HO-1, GCLC and NQO1 in the Nrf2/ARE signaling pathway, thereby increasing the activity of antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and reduced catalase (CAT) in liver cells. Furthermore, the rEPS-2 can be used and modulate the gut microbiota of mice with liver injury caused by CCl4 . CONCLUSIONS: These results suggest that rEPS-2 has promising potential to serve as hepatoprotective agents. © 2022 Society of Chemical Industry.

Purification, Structural Characteristics, and Biological Activities of Exopolysaccharide Isolated From Leuconostoc mesenteroides SN-8.

In this study, a novel exopolysaccharide (EPS) was extracted from Leuconostoc mesenteroides Shen Nong's (SN)-8 which can be obtained from Dajiang. After the purification step, EPS-8-2 was obtained with molecular weights of 1.46 × 105 Da. The structural characterization of EPS indicated that the EPS belonged to the class polysaccharide, mainly composed of glucan and also contained certain mannose residues that were found to be connected by α-1,6 glycosidic bonds. Moreover, the results demonstrated that EPS displayed a significant capacity to scavenge free radical to some extent, and this anti-oxidant potential was found to be concentration dependent. The results further revealed that EPS displayed a significant inhibitory potential on the growth of HepG2 cells by promoting apoptosis and induced cell cycle arrest in G1 and G2 phases. Overall, these results suggested that EPS can be explored as a possible anti-cancer agent.

Effect of inlet temperature on the physicochemical properties of spray-dried seed-watermelon seed protein powder.

Here, we studied the effects of inlet temperature on the physicochemical properties of the hydrolyzed protein (seed-watermelon seed hydrolyzed protein [SWSP]) powder in seed-watermelon seeds. The inlet temperature of the study was in the range of 150 to 180 °C, and the remaining experimental parameters remained constant, that is, the feed flow rate was 0.2 L/hr, the concentration of maltodextrin was 30%, and the outlet temperature was 80 °C. We studied the water activity and moisture content, bulk density, flowability (Carr index and Hausner ratio), angle of repose, solubility, color, hygroscopicity, powder morphology, particle size, crystallinity, and odor of the sample. Inlet temperature of 170 to 180 °C reduced the moisture content and increased the particle size. It was found that the value of measured water activity was less than 0.5, which helped in maintaining stability of the sample. Powders produced at the temperatures showed smoother particle surfaces, whereas higher inlet temperature showed spherical particles with some shrinkage as analyzed by scanning electron microscope. The inlet temperature affected the color of the sample, thus at high temperature, the sample had a brighter color. The sample was approximately 18% crystalline. At a preparation temperature of 160 °C, the sample showed significant antioxidant activity (P < 0.05).

Purification, characterization and antitumor activity of an exopolysaccharide produced by Bacillus velezensis SN-1.

A capsular polysaccharides (CPS) producer Bacillus velezensis SN-1 (B. velezensis SN-1) was isolated in Da-jiang, China. We used ultrasonic extraction to obtain CPS from a culture of B. velezensis SN-1 at a yield of 755 mg/L. Using gel permeation chromatography (GPC), CPS was separated into a single peak with a molecular weight of 1.46 × 105 Da. Its structures were characterized by gas chromatography (GC), methylation, Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR). The CPS was identified as a polysaccharide with a highly branched main chain of mannose with (1 â†’ 3) connections. Moreover, our results revealed that CPS has the capacity to scavenge DPPH radical, hydroxyl radical, ABTS radical and oxygen radical in a manner that relied on concentration. Anti-neoplastic analysis showed that CPS displayed significant anti-tumor activity towards HepG-2 tumor cells. Above findings indicate that CPS generated by B. velezensis SN-1 may be adapted for use as a natural antioxidant in foodstuffs and as an anti-tumor drug.

Structural characterization and antioxidant potential of a novel exopolysaccharide produced by Bacillus velezensis SN-1 from spontaneously fermented Da-Jiang.

The aim of this study was to characterize the exopolysaccharide (EPS) produced by Bacillus velezensis SN-1 (B. velezensis SN-1) (EPS-SN-1), which was isolated from the fermented Da jiang. The microbe made crude exopolysaccharides EPS-SN-1 was produced throughout the bacterial growth period, and the highest yield (2.7 g/L) was obtained with sucrose as the carbon source. As per high performance liquid chromatography (HPLC), EPS-SN-1 is a heteropolysaccharide consisting of glucose, mannose and fructose, with a high molecular weight of 2.21 × 105 Da. FTIR spectra further indicated the presence of hydroxyl and carbonyl groups, and NMR analysis confirmed both α- and ß-glycosidic bonds. Furthermore, differential scanning calorimetry (DSC) showed that EPS-SN-1 has high thermal stability with fusion point of 270.7 °C. Finally, EPS-SN-1 demonstrated strong antioxidant capacity via its ability to scavenge hydroxyl radical (•OH), 1,1-diphenyl-2-picrylhydrazyl (DPPH•) radical, ABTS radical (ABTS•+) and oxygen radical (O2-•). Taken together, EPS-SN-1 is a promising natural antioxidant and probiotic with potential applications in the food industry.

Extraction and biological activity of exopolysaccharide produced by Leuconostoc mesenteroides SN-8.

An exopolysaccharide (EPS)-producing strain SN-8 isolated from Dajiang was identified as Leuconostoc mesenteroides. When sucrose was used as the carbon source for fermentation, the output of EPS was 2.42 g/L. High performance liquid chromatography analysis confirmed the presence of monomers such as glucan and mannose. The molecular weight detection value is 2.0 × 105 Da. Fourier transform infrared spectroscopy displayed the EPS had the basic skeleton and functional groups of a typical polysaccharide structure. Scanning electron microscopy showed smooth surfaces and compact structure. Thermal performance analysis showed that the highest heat resistance temperature of the EPS was 80 °C. Compared with vitamin C, its hydroxyl radical scavenging rate was as high as 32% and 1,1-diphenyl-2-picrylhydrazyl scavenging rate was as high as 40% under the same concentration. The peanut oil was the most emulsifiable at a concentration of 1.5 mg/mL, and the emulsification index was 0.55. These results might show that the EPS had high application value.

Effects of skim milk fermented with Lactobacillus plantarum WW on the constitutions of rats fed a high-fat diet.

This study investigated the effects of Lactobacillus plantarum WW-fermented skim milk (FSM) on the physiques of rats fed a high-fat diet and the mechanism of lipid lowering. Sprague-Dawley rats were randomly divided into a normal diet group (A), a high-fat diet group (B), a skim milk diet group (C), and an L. plantarum WW FSM diet group (D). After 12-wk feeding, we found that treatment with L. plantarum WW FSM could significantly alleviate symptoms in the pathological group. Meanwhile, high-throughput sequencing analysis showed that L. plantarum WW FSM also had a certain regulatory effect on the intestinal microorganisms in rats, which can increase the number of lactic acid bacteria and Bacteroides in the intestine. More importantly, real-time quantitative PCR and Western blot analysis showed that the probiotic was also involved in the expression of genes related to fat metabolism, especially the PPARB and CEBPB genes. Our study supports the hypothesis that the WW strain of L. plantarum could be a potential probiotic to be used in functional foods to alter lipid metabolism and reduce cholesterol levels.