Comprehensive Evaluation of Probiotic Property, Hypoglycemic Ability and Antioxidant Activity of Lactic Acid Bacteria

Chemical characteristics, antioxidant capacity, bacterial community, and metabolite composition of mulberry silage ensiling with lactic acid bacteria

Mulberry has high crude protein and biologically active compounds but is difficult to be ensiled due to the lack of adequate epiphytic LAB. This study aimed to investigate the effects of inoculation with Lactiplantibacillus plantarum and Pediococcus pentosaceus isolated from mulberry with higher antioxidant capacity alone or in combination with Streptococcus bovis on chemical characteristics, antioxidant capacity, bacterial community, and metabolite composition of mulberry silage. The results showed that all inoculation groups had higher dry matter and lower pH than the control group, particularly in LP (dry matter, DM, 32.03% and pH = 4.44) and LP_PP_SB (DM, 31.68% and pH = 4.26) after 60 days of ensiling. Ammonia nitrogen (AN) content was the lowest in both LP_SB and LP_PP_SB groups, which were 1.86 g/kg FM and 1.05 g/kg FM, respectively, (P < 0.05). Only the LP_PP_SB group showed increased polyunsaturated fatty acids (PUFA, 1.2851 g/kg DM, P < 0.05) than the control group. Ferric-reducing antioxidant power (FRAP) values were increased in all inoculation-treated groups compared with the control group (P < 0.05). 2,2-Diphenyl-1-picrylhydrazyl (DDPH), 3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and FRAP exhibited the highest levels in the LP_PP- and LP_PP_SB-treated groups. Enterobacter was dominant in both the control and SB-treated groups, and the relative abundance was 41.18% and 32.35%, respectively (P < 0.05). The relative abundance of Lactiplantibacillus was higher in the LP-, LP_PP-, and LP_SB-treated groups (81.84%-82.69%). Relative abundance of Pediococcus was higher in the PP-, PP_SB-, and LP_PP_SB-treated groups (74.27%-85.27%). Untargeted metabolomics analysis results showed that five flavonoids (apigenin, eriodictyol, quercetin-3-glucoside, rutin, and kaempferol-3-O-rutinoside)were upregulated in all inoculation groups (except for the SB-treated groups). Among them, eriodictyol was both positively correlated with ABTS and FRAP and also showed the highest relative abundance in the LP_PP- and LP_PP_SB-treated groups. To the best of our knowledge, this study was the first to investigate the relationship between inoculants of epiphytic lactic acid bacteria and antioxidant capacity by 16s rRNA Illumina sequencing technology and untargeted metabolomics analysis, respectively. Consequently, inoculated L. plantarum, P. pentosaceus alone, respectively, or in combination with S. bovis increased the relative abundance of Lactiplantibacillus and Pediococcus and decreased the relative abundance of Enterobacter, particularly in the LP_PP_SB-treated group. In addition, inoculants could increase the relative abundance of five flavonoids (apigenin, eriodictyol, quercetin-3-glucoside, rutin, and kaempferol-3-O-rutinoside), especially eriodictyol to improve the antioxidant capacity of mulberry silage.

Bacterial diversity of stingless bee honey in Yunnan, China: isolation and genome sequencing of a novel acid-resistant Lactobacillus pentosus (SYBC-MI) with probiotic and L. tryptophan producing potential via millet fermentation

Stingless bee (Hymenoptera, Apidae, and Trigona) honey is a remarkable "miracle liquid" with a wide range of medical benefits for conditions including gastroenteritis, cataracts, and wound healing. Our study aimed to isolate, identify, and characterize acid-resistant Lactobacillus spp. from sour honey distributed in Yunnan, China. To assess the safety of an entirely novel Lactobacillus pentosus strain, S4 (OM618128), based on probiotic property evaluation and whole-genome sequencing analysis. A 16S rRNA gene high-throughput sequencing analysis showed that Lactobacillus was abundant at the genus level in sour honey. Seven Lactobacillus strains (viz. S1-7) were isolated from sour honey using a multiple-anaerobic culture enrichment method. One potential acid-resistant isolate, Lactobacillus sp. S4, was obtained after screening the seven Lactobacillus isolates, and it had the highest lactic acid production (17.62 g/L), followed by Lactobacillus sp. S3 (17.07 g/L). Phylogenetic and comparative analyses of conserved sequence regions have shown that all seven strains are phylogenetically located in the Lactobacillus pentosus sub-cluster. In L. pentosus SYBC-MI, there is a circular chromosome (3288615 bps) and 11,466 bps plasmids. GC content is 44.03%. The number of predicted genes is 3,129, with 16 rRNAs and 74 tRNAs present. During the fermentation of foxtail millet by seven Lactobacillus pentosus (S1-7) strains isolated from sour honey, a potential tryptophan accumulating isolate, Lactobacillus pentosus S4, was obtained, which could reach a maximum tryptophan content of 238.43 mgL-1 that is 1.80 times the initial tryptophan content in the fermentation broth. This strain has strong acid tolerance, salt tolerance, and fermentation acid production abilities. This strain degrades nitrite at a rate of over 99%, and it has high probiotic potential as well. This project has established a solid foundation for further exploring the excellent lactic acid bacteria in sour honey. It is also investigating the key taxa and their role in the environment. According to the results of our studies, these LAB isolates provide a lot of potential for use in the future, as a source of probiotics for human, animals, and starter cultures for food applications.

Effects of Probiotic-Enriched Minas Cheese (Lactobacillus acidophilus La-05) on Cardiovascular Parameters in 5/6 Nephrectomized Rats

Dairy foods have become an interest in chronic kidney disease (CKD) due to their nutritional profile, which makes them a good substrate for probiotics incorporation. This study evaluated the effect of probiotic-enriched Minas cheese with Lactobacillus acidophilus La-05 in an experimental rat model for CKD on cardiac, inflammatory, and oxidative stress parameters. Male Wistar rats were divided into 4 groups (n = 7/group): 5/6 nephrectomy + conventional Minas cheese (NxC); 5/6 nephrectomy + probiotic Minas cheese (NxPC); Sham + conventional Minas cheese (ShamC); Sham + probiotic Minas cheese (ShamPC). Offering 20 g/day of Minas cheese with Lact. acidophilus La-05 (108-109 log CFU/g) for 6 weeks. The cardiomyocyte diameter was determined. Superoxide dismutase (SOD) activity in plasma, heart, kidney, and colon tissue was performed. At the end of supplementation, no significant changes in lipid profile and renal parameters were found. The NxPC group showed a decrease in cardiomyocyte diameter compared to the NxC group (16.99 ± 0.85 vs. 19.05 ± 0.56 μm, p = 0.0162); also they showed reduced plasmatic SOD activity (502.8 ± 49.12 vs. 599.4 ± 94.69 U/mL, p < 0.0001). In summary, probiotic-enriched Minas cheese (Lact. acidophilus La-05) consumption suggests a promisor cardioprotective effect and was able to downregulate SOD activity in a rat model of CKD.

Supplementation with the Probiotic Strains Bifidobacterium longum and Lactiplantibacillus rhamnosus Alleviates Glucose Intolerance by Restoring the IL-22 Response and Pancreatic Beta Cell Dysfunction in Type 2 Diabetic Mice

Type 2 diabetes (T2D) is known as adult-onset diabetes, but recently, T2D has increased in the number of younger people, becoming a major clinical burden in human society. The objective of this study was to determine the effects of Bifidobacterium and Lactiplantibacillus strains derived from the feces of 20 healthy humans on T2D development and to understand the mechanism underlying any positive effects of probiotics. We found that Bifidobacterium longum NBM7-1 (Chong Kun Dang strain 1; CKD1) and Lactiplantibacillus rhamnosus NBM17-4 (Chong Kun Dang strain 2; CKD2) isolated from the feces of healthy Korean adults (n = 20) have anti-diabetic effects based on the insulin sensitivity. During the oral gavage for 8 weeks, T2D mice were supplemented with anti-diabetic drugs (1.0-10 mg/kg body weight) to four positive and negative control groups or four probiotics (200 uL; 1 × 109 CFU/mL) to groups separately or combined to the four treatment groups (n = 6 per group). While acknowledging the relatively small sample size, this study provides valuable insights into the potential benefits of B. longum NBM7-1 and L. rhamnosus NBM17-4 in mitigating T2D development. The animal gene expression was assessed using a qRT-PCR, and metabolic parameters were assessed using an ELISA assay. We demonstrated that B. longum NBM7-1 in the CKD1 group and L. rhamnosus NBM17-4 in the CKD2 group alleviate T2D development through the upregulation of IL-22, which enhances insulin sensitivity and pancreatic functions while reducing liver steatosis. These findings suggest that B. longum NBM7-1 and L. rhamnosus NBM17-4 could be the candidate probiotics for the therapeutic treatments of T2D patients as well as the prevention of type 2 diabetes.

A Rice Hazards Risk Assessment Method for a Rice Processing Chain Based on a Multidimensional Trapezoidal Cloud Model

Rice is common in the human diet, making rice safety issues important. Moreover, rice processing safety is key for rice security, so rice processing chain risk assessment is critical. However, methods proposed to assess the rice processing chain risk have issues, such as the use of unreasonable thresholds for the rice processing chain and fixed weight. To solve these problems, we propose a risk assessment method for the rice processing chain based on a multidimensional trapezoidal cloud model. First, an evaluation model based on a multidimensional trapezoidal cloud model was established. Based on the historical evaluation results, Atanassov’s interval-valued intuition language numbers (AIVILNs) were introduced to determine the cloud model’s parameters. Second, the concept of dynamic weight was introduced to integrate the static and dynamic weights. An exponential function was used to construct dynamic weighting mechanisms, and the analytic hierarchy stage (AHP) was used to construct a static weight. The proposed method was validated by 104 sets of rice processing chain data, and the results show that the method could evaluate the risk level of the rice processing chain more accurately and reasonably than other methods, indicating that it can provide a sound decision-making basis for food safety supervision authorities.

Probiotic Properties Including the Antioxidant and Hypoglycemic Ability of Lactic Acid Bacteria from Fermented Grains of Chinese Baijiu

In this study, lactic acid bacteria (LAB) strains were isolated from fermented grains of traditional Chinese Baijiu, and their probiotic properties were characterized. Eleven out of 29 LAB strains showed good tolerance to the gastrointestinal tract and bile salts. The surface characteristics (auto-aggregation, co-aggregation, hydrophobicity), safety (hemolytic and antibiotic sensitivity), antibacterial activity against three foodborne pathogens, and antioxidant and hypoglycemic properties of the 11 LAB strains were investigated. Principal component analysis (PCA) was used to comprehensively evaluate LAB strains and their probiotic properties. It was found that Weissella cibaria (OP288150), Pediococcus acidilactici (OP288151), Pediococcus pentosaceus (OP288154), Pediococcus pentosaceus (OP288156) and Levilactobacillus brevis (OP288158) showed high probiotic properties, with potential for commercial development. The results also demonstrated that fermented grains of Chinese Baijiu can be used as a source of high-quality probiotics.

Efficacy of simultaneous hexavalent chromium biosorption and nitrogen removal by the aerobic denitrifying bacterium Pseudomonas stutzeri YC-34 from chromium-rich wastewater

The impact of high concentrations of heavy metals and the loss of functional microorganisms usually affect the nitrogen removal process in wastewater treatment systems. In the study, a unique auto-aggregating aerobic denitrifier (Pseudomonas stutzeri strain YC-34) was isolated with potential applications for Cr(VI) biosorption and reduction. The nitrogen removal efficiency and denitrification pathway of the strain were determined by measuring the concentration changes of inorganic nitrogen during the culture of the strain and amplifying key denitrification functional genes. The changes in auto-aggregation index, hydrophobicity index, and extracellular polymeric substances (EPS) characteristic index were used to evaluate the auto-aggregation capacity of the strain. Further studies on the biosorption ability and mechanism of cadmium in the process of denitrification were carried out. The changes in tolerance and adsorption index of cadmium were measured and the micro-characteristic changes on the cell surface were analyzed. The strain exhibited excellent denitrification ability, achieving 90.58% nitrogen removal efficiency with 54 mg/L nitrate-nitrogen as the initial nitrogen source and no accumulation of ammonia and nitrite-nitrogen. Thirty percentage of the initial nitrate-nitrogen was converted to N₂, and only a small amount of N₂O was produced. The successful amplification of the denitrification functional genes, norS, norB, norR, and nosZ, further suggested a complete denitrification pathway from nitrate to nitrogen. Furthermore, the strain showed efficient aggregation capacity, with the auto-aggregation and hydrophobicity indices reaching 78.4 and 75.5%, respectively. A large amount of protein-containing EPS was produced. In addition, the strain effectively removed 48.75, 46.67, 44.53, and 39.84% of Cr(VI) with the initial concentrations of 3, 5, 7, and 10 mg/L, respectively, from the nitrogen-containing synthetic wastewater. It also could reduce Cr(VI) to the less toxic Cr(III). FTIR measurements and characteristic peak deconvolution analysis demonstrated that the strain had a robust hydrogen-bonded structure with strong intermolecular forces under the stress of high Cr(VI) concentrations. The current results confirm that the novel denitrifier can simultaneously remove nitrogen and chromium and has potential applications in advanced wastewater treatment for the removal of multiple pollutants from sewage.