1H NMR-based chemometric metabolomics characterization of soymilk fermented by Bacillus subtilis BSNK-5

Study on the quality of soybean proteins fermented by Bacillus subtilis BSNK-5: Insights into nutritional, functional, safety, and flavor properties

Microbial fermentation emerges as a promising strategy to elevate the quality of soybean proteins in food industry. This study conducted a comprehensive assessment of the biotransformation of four types of soybean proteins by Bacillus subtilis BSNK-5, a proteinase-rich bacterium. BSNK-5 had good adaptability to each protein. Soluble protein, peptides and free amino acids increased in fermented soybean proteins (FSPs) and dominant after 48-84 h fermentation, enhancing nutritional value. Extensive proteolysis of BSNK-5 also improved antioxidant and antihypertensive activities, reaching peak level after 48 h fermentation. Furthermore, excessive proteolysis effectively enhanced the generation of beneficial spermidine without producing toxic histamine after fermentation, and formed the flavor profile with 56 volatiles in 48 h FSPs. Further degradation of amino acids showed a positive correlation with off-flavors, particularly the enrichment of 3-methylbutanoic acid. These findings establish a theoretical foundation for regulating moderate fermentation by BSNK-5 to enabling the high-value utilization of soybean protein.

Profiling of Metabolites in a Fermented Soy Dietary Supplement Reinforces its Role in the Management of Intestinal Inflammation

SCOPE

Gastro-AD (GAD) is a soy flour derived product that undergoes an industrial fermentation with Lactobacillus delbrueckii R0187 and has demonstrated clinical effects in gastroesophageal reflux and peptic ulcer symptom resolution. The aim of this study is to describe and link GAD's metabolomic profile to plausible mechanisms that manifest and explain the documented clinical outcomes.

METHODS AND RESULTS

1H NMR spectroscopy with multivariate statistical analysis is used to characterize the prefermented soy flour and GAD products. The acquired spectra are screened using various resources and the molecular assignments are confirmed using total correlation spectroscopy (TOCSY). Peaks corresponding to different metabolites are integrated and compared between the two products for relative changes. HPLC and GC are used to quantify some specific molecules. NMR analyses demonstrate significant changes in the composition of various assigned bioactive moieties. HPLC and GC analysis demonstrate deglycation of isoflavones after fermentation, resulting in estrogenically active secondary metabolites that have been previously shown to help to reduce inflammation.

CONCLUSION

The identification of bioactive molecules, such as genistein and SCFAs, capable of modulating anti-inflammatory signaling cascades in the stomach's gastric and neuroendocrine tissues can explain the reported biological effects in GAD and is supported by in vivo data.

Untargeted metabolomics revealed the effect of soybean metabolites on poly(γ-glutamic acid) production in fermented natto and its metabolic pathway

BACKGROUND

Natto mucus is mainly composed of poly(γ-glutamic acid) (γ-PGA), which affects the sensory quality of natto and has some effective functional activities. The soybean metabolites that cause different γ-PGA contents in different fermented natto are unclear.

RESULTS

In this study, we use untargeted metabolomics to analyze the metabolites of high-production γ-PGA natto and low-production γ-PGA natto and their fermented substrate soybean. A total of 257 main significantly different metabolites with the same trend among the three comparison groups were screened, of which 114 were downregulated and 143 were upregulated. Through the enrichment of metabolic pathways, the metabolic pathways with significant differences were purine metabolism, nucleotide metabolism, fructose and mannose metabolism, anthocyanin biosynthesis, isoflavonoid biosynthesis and the pentose phosphate pathway.

CONCLUSION

For 114 downregulated main significantly different metabolites with the same trend among the three comparison groups, Bacillus subtilis (natto) may directly decompose them to synthesize γ-PGA. Adding downregulated substances before fermentation or cultivating soybean varieties with the goal of high production of such substances has a great effect on the production of γ-PGA by natto fermentation. The enrichment analysis results showed the main pathways affecting the production of γ-PGA by Bacillus subtilis (natto) using soybean metabolites, which provides a theoretical basis for the production of γ-PGA by soybean and promotes the diversification of natto products. © 2023 Society of Chemical Industry.

Exploring metabolic responses and pathway changes in CHO-K1 cells under varied aeration conditions and copper supplementations using 1 H NMR-based metabolomics

The optimization of bioprocess for CHO cell culture involves careful consideration of factors such as nutrient consumption, metabolic byproduct accumulation, cell growth, and monoclonal antibody (mAb) production. Valuable insights can be obtained by understanding cellular physiology to ensure robust and efficient bioprocess. This study aims to improve our understanding of the CHO-K1 cell metabolism using 1 H NMR-based metabolomics. Initially, the variations in culture performance and metabolic profiles under varied aeration conditions and copper supplementations were thoroughly examined. Furthermore, a comprehensive metabolic pathway analysis was performed to assess the impact of these conditions on the implicated pathways. The results revealed substantial alterations in the pyruvate metabolism, histidine metabolism, as well as phenylalanine, tyrosine and tryptophan biosynthesis, which were especially evident in cultures subjected to copper deficiency conditions. Conclusively, significant metabolites governing cell growth and mAb titer were identified through orthogonal partial least square-discriminant analysis (OPLS-DA). Metabolites, including glycerol, alanine, formate, glutamate, phenylalanine, and valine, exhibited strong associations with distinct cell growth phases. Additionally, glycerol, acetate, lactate, formate, glycine, histidine, and aspartate emerged as metabolites influencing cell productivity. This study demonstrates the potential of employing 1 H NMR-based metabolomics technology in bioprocess research. It provides valuable guidance for feed medium development, feeding strategy design, bioprocess parameter adjustments, and ultimately the enhancement of cell proliferation and mAb yield.

Bacillus sp. as a microbial cell factory: Advancements and future prospects

Bacillus sp. is one of the most distinctive gram-positive bacteria, able to grow efficiently using cheap carbon sources and secrete a variety of useful substances, which are widely used in food, pharmaceutical, agricultural and environmental industries. At the same time, Bacillus sp. is also recognized as a safe genus with a relatively clear genetic background, which is conducive to the industrial production of target metabolites. In this review, we discuss the reasons why Bacillus sp. has been so extensively studied and summarize its advances in systems and synthetic biology, engineering strategies to improve microbial cell properties, and industrial applications in several metabolic engineering applications. Finally, we present the current challenges and possible solutions to provide a reliable basis for Bacillus sp. as a microbial cell factory.

A systematic review on the flavor of soy-based fermented foods: Core fermentation microbiome, multisensory flavor substances, key enzymes, and metabolic pathways

The characteristic flavor of fermented foods has an important impact on the purchasing decisions of consumers, and its production mechanisms are a concern for scientists worldwide. The perception of food flavor is a complex process involving olfaction, taste, vision, and oral touch, with various senses contributing to specific properties of the flavor. Soy-based fermented products are popular because of their unique flavors, especially in Asian countries, where they occupy an important place in the dietary structure. Microorganisms, known as the souls of fermented foods, can influence the sensory properties of soy-based fermented foods through various metabolic pathways, and are closely related to the formation of multisensory properties. Therefore, this review systematically summarizes the core microbiome and its interactions that play an active role in representative soy-based fermented foods, such as fermented soymilk, soy sauce, soybean paste, sufu, and douchi. The mechanism of action of the core microbial community on multisensory flavor quality is revealed here. Revealing the fermentation core microbiome and related enzymes provides important guidance for the development of flavor-enhancement strategies and related genetically engineered bacteria.

Effect of a co-fermentation system with high-GABA-yielding strains on soymilk properties: microbiological, physicochemical, and aromatic characterisations

Biosynthesis is the safest method for preparing GABA; however, there are not enough GABA-producing strains to provide an effective resource. The purpose of this study was to determine the feasibility of using Lactobacillus fermentum SMN10-3(A) and Lactococcus lactis SMN15-6(B) to study the effects of strain complex pairing on the GABA formation, flavour, and metabolic pathways of fermented soymilk. It was found that group A2B1 had the highest acid production rate, GABA yield (1.76 ± 0.01 mg/mL), and flavour compound content. A total of 55 differential metabolites were produced after fermentation, of which 28 dominated by hexanal were significantly downregulated and 26 dominated by alcohols were significantly upregulated. The significant metabolic pathways involved were d-alanine, taurine and hypotaurine, and selenocompound metabolism. Finally, the components contributing to the aroma of fermented soymilk were identified, which included 2-pentylfuran and 2-butyl-2-octenal. These results provide a theoretical basis for future research on GABA-rich fermented foods.

Effects of Bacillus subtilis BSNK-5-Fermented Soymilk on the Gut Microbiota by In Vitro Fecal Fermentation

The gut microbiota of soymilk intervention is beneficial to maintaining human health. Bacillus subtilis fermented soymilk has brought much interest, due to its richness of thrombolytic nattokinase and the strain of potential probiotic properties. In this study, soymilk was fermented by B. subtilis BSNK-5, and the BSNK-5-fermented soymilk (SMF) on the production of short chain fatty acids (SCFAs) and the regulation of fecal microbiota was initially evaluated by in vitro fecal fermentation. SMF supplementation obviously increased the levels of SCFAs from 32.23 mM to 49.10 mM, especially acetic acid, propionic acid, and isobutyric acid. Additionally, SMF changed the composition and microbial diversity of gut microbiota. After 24 h of anaerobic incubation in vitro, SMF decreased the Firmicutes/Bacteroidota ratio favoring weight loss, increased Lachnospiraceae_UCG-004 and the other beneficial bacteria producing SCFAs, as well as suppressing pathogenic Streptococcus genus. These results revealed the potential use of BSNK-5-fermented soymilk as a potential candidate to promote gut health.

Optimization of Sporulation Conditions for Bacillus subtilis BSNK-5

Bacillus subtilis spores have important biological applications; however, high spore-cell densities and sporulation efficiencies in fermentation is poorly reported. This study systematically analyzed the spore densities and formation efficiency of B. subtilis BSNK-5 in different culture substrates. A response surface regression equation was established based on the results of single factor and Box–Behnken experimental designs. The optimal medium formulation, as predicted from the equation, consisted of soluble starch at 3 g·L−1, soybean flour at 12 g·L−1, and MgSO4 at 5 g·L−1. The spore yield reached 2.43 × 109 CFU·mL−1, and the sporulation rate was 83.3%, which was nearly three times higher than before optimization using an optimized medium at 36 °C and 200 rpm for 60 h.

Occurrence, Diversity, and Character of Bacillaceae in the Solid Fermentation Process of Strong Aromatic Liquors

Strong aromatic liquors, also known as strong aromatic Baijiu (SAB) in China, are manufactured by solid fermentation, with a multi-microbe mixing and cooperative fermentation process that uses Daqu as a brewing starter. Bacillaceae have a specific action in food fermentation, such as soybean and wine, and more recent studies have found Bacillaceae play important roles in the SAB making industry. This review describes the diversity, functionality, and influence of Bacillaceae in Daqu, pit mud, Zaopei, Huangshui within making processes of SAB. Furthermore, aromatic flavor components from the Bacillaceae metabolism of SAB are discussed in this review. Ultimately, the resulting improvements and deeper understanding will benefit practical efforts to apply representatives of Bacillaceae in improving the quality of SAB as well as biological control of the micro-ecological environment of brewing.

Genistein-Opportunities Related to an Interesting Molecule of Natural Origin

Nowadays, increasingly more attention is being paid to a holistic approach to health, in which diet contributes to disease prevention. There is growing interest in functional food that not only provides basic nutrition but has also been demonstrated to be an opportunity for the prevention of disorders. A promising functional food is soybean, which is the richest source of the isoflavone, genistein. Genistein may be useful in the prevention and treatment of such disorders as psoriasis, cataracts, cystic fibrosis, non-alcoholic fatty liver disease and type 2 diabetes. However, achievable concentrations of genistein in humans are low, and the use of soybean as a functional food is not devoid of concerns, which are related to genistein's potential side effects resulting from its estrogenic and goitrogenic effects.

Novel Millet-Based Flavored Yogurt Enriched With Superoxide Dismutase

Superoxide dismutase (SOD) is an important antioxidant enzyme with different physiological functions, which can be used as a nutritional fortifier in food. Cereal-based fermented products are becoming popular worldwide. In this study, novel millet-based flavored yogurt enriched with SOD was developed. Lactiplantibacillus plantarum subsp. plantarum was screened, which manufactured SOD activity of 2476.21 ± 1.52 U g^-1. The SOD content of millet yogurt was 19.827 ± 0.323 U mL^-1, which was 63.01, 50.11, and 146.79% higher than that of Bright Dairy Yogurt 1911, Junlebao and Nanjing Weigang, respectively. Fifty-four volatile flavor substances and 22,571 non-volatile flavor substances were found in yogurt. Compared to traditional fermented yogurt, 37 non-volatile metabolites in yogurt with millet enzymatic fermentation broth were significantly upregulated, including 2-phenyl ethanol, hesperidin, N-acetylornithine and L-methionine, which were upregulated by 3169.6, 228.36, 271.22, and 55.67 times, respectively, thereby enriching the sensory and nutritional value of yogurt. Moreover, the manufacture of unpleasant volatile flavor substances was masked, making the product more compatible with consumers' tastes.

Metabolomics Approaches for the Comprehensive Evaluation of Fermented Foods: A Review

Fermentation is an important process that can provide new flavors and nutritional and functional foods, to deal with changing consumer preferences. Fermented foods have complex chemical components that can modulate unique qualitative properties. Consequently, monitoring the small molecular metabolites in fermented food is critical to clarify its qualitative properties and help deliver personalized nutrition. In recent years, the application of metabolomics to nutrition research of fermented foods has expanded. In this review, we examine the application of metabolomics technologies in food, with a primary focus on the different analytical approaches suitable for food metabolomics and discuss the advantages and disadvantages of these approaches. In addition, we summarize emerging studies applying metabolomics in the comprehensive analysis of the flavor, nutrition, function, and safety of fermented foods, as well as emphasize the applicability of metabolomics in characterizing the qualitative properties of fermented foods.

Antioxidant Effect of Lactobacillus fermentum CQPC04-Fermented Soy Milk on D-Galactose-Induced Oxidative Aging Mice

The aim of this study is to evaluate the changes in soy isoflavones and peptides in soy milk after lactic acid bacterial fermentation, and explore the positive effects of fermented soy milk on an oxidative aging mouse model induced with D-galactose. We found that free soybean isoflavones and peptides increased after soy milk was fermented by Lactobacillus fermentum CQPC04. The in vivo results indicated that L. fermentum CQPC04-fermented soy milk enhanced the organ index of the liver and spleen, and improved the pathological morphology of the liver, spleen, and skin. L. fermentum CQPC04-fermented soy milk increased the enzymatic activity of glutathione peroxidase (GSH-Px), total superoxide dismutase (T-SOD), and catalase (CAT), increased glutathione (GSH), but decreased the levels of nitric oxide (NO) and malondialdehyde (MDA) in serum, liver, and brain tissues of oxidative aging mice. The above mentioned fermented soy milk also increased the levels of collagen I (Col I), hyaluronic acid (HA), and collagen III (Col III), and decreased the levels of advanced glycation End products (AGEs) and hydrogen peroxide (H₂O₂). The RT-qPCR results showed that L. fermentum CQPC04-fermented soy milk upregulated the mRNA expression of nuclear factor erythroid 2?related factor (Nrf2), heme oxygenase-1 (HMOX1), quinone oxido-reductase 1 (Nqo1), neuronal nitric oxide synthase (NOS1), endothelial nitric oxide synthase (NOS3), Cu/Zn–superoxide dismutase (Cu/Zn-SOD), Mn–superoxide dismutase (Mn-SOD), and CAT, but downregulated the expression of inducible nitric oxide synthase (NOS2) and glutamate cysteine ligase modifier subunit (Gclm) in liver and spleen tissues. Lastly, the fermented soy milk also increased the gene expression of Cu/Zn-SOD, Mn-SOD, CAT, GSH-Px, matrix metalloproteinases 1 (TIMP1), and matrix metalloproteinases 2 (TIMP2), and decreased the expression of matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9) in skin tissue. In conclusion, L. fermentum CQPC04-fermented soy milk was able to satisfactorily delay oxidative aging effects, and its mechanism may be related to the increase in free soy isoflavones and peptides.