Background: Compared with lactic acid-producing probiotics, spore-producing probiotics such as Bacillus subtilis (BS) and Bacillus natto (BN) exhibited superior metabolic capacity and stress resistance and are more suitable for industrial applications. However, limited understanding of their nutritional and intestinal health mechanisms has constrained their food potential. Objectives: This review systematically expounded on the ‘triple mechanism’ of BS and BN and their effects on intestinal nutrition, immunity and metabolism benefit for the first time. Methods: We searched PubMed, Scopus, Web of Science, and Google Scholar for studies on livestock, model organisms, and human research from 2000 to 2025. After evaluating relevance and eligibility, 115 articles were included. Results: Firstly, by secreting various digestive enzymes, BS and BN directly enhanced the small intestine digestive and absorptive efficiency and promoted animal growth. In particular, BN significantly increases calcium absorption in postmenopausal women. Secondly, as the antigen carrier that induced intestinal mucosal immunity, BS and BN enhanced the host’s defense ability by strengthening the expression of tight junction proteins, mucins, and inflammatory factors and bidirectionally regulated constipation and acute diarrhea in the human body. Thirdly, they reshaped the structure of the intestinal microbiota and their metabolic profile in the form of the gut–liver/gut–adipose axis, including enriching beneficial bacteria, activating lipid metabolism pathways such as PI3K/AKT and AMPK/SREBP, and regulating liver targets such as PPAR and CD36, thereby reducing insulin resistance and liver injury and maintaining overall metabolic homeostasis. Conclusions: Bacillus subtilis and Bacillus natto mediated their probiotic benefits through a gut-centric, multi-system regulatory strategy, involving nutrient utilization, immune homeostasis, and microbial–host metabolic interactions. This integrated mechanism provided a robust foundation for their targeted application in functional formulations and fermented food science.

Min Yang, Yuguang He, Xinyu Miao, Mubai Sun, Honghong Niu , Mei Hua, Da Li, Hongyan Xu, and Jinghui Wang. J. Microbiol. Biotechnol. 2026;36:1-12. https://doi.org/10.4014/jmb.2510.10031

Obesity is characterized by abnormal adipose tissue expansion and energy metabolism imbalance. Browning of white adipose tissue (WAT), wherein white adipocytes acquire thermogenic properties similar to brown adipose tissue, represents a key mechanism for increasing energy expenditure. Although ginseng (Panax ginseng C.A. Meyer) is widely recognized as a health-promoting botanical, its role in WAT browning has not been fully elucidated. This review summarizes evidence that ginseng and its bioactive components regulate major thermogenic pathways, including β-adrenergic/cyclic adenosine monophosphate-protein kinase (cAMP-PKA) signaling, AMP-activated protein kinase (AMPK), and the peroxisome proliferator-activated receptor γ (PPARγ)/coactivator 1α (PGC-1α) axis, thereby upregulating key markers such as uncoupling protein 1 (UCP1), PR domain containing 16 (PRDM16) and type II iodothyronine deiodinase (DIO2). These effects promote mitochondrial function and fatty acid oxidation, reduce lipogenesis, alleviate inflammation, and improve insulin sensitivity, collectively fostering a microenvironment conducive to browning. Furthermore, fermentation has been found to enhance the bioactivity and thermogenic efficacy of ginseng. Recent evidence indicates that gut microbiota and their metabolites—such as short-chain fatty acids, unsaturated fatty acids, and bile acids—play a notable role in ginseng-induced thermogenesis via receptors including G-protein-coupled receptor 41/43 (GPR41/43), takeda G-protein-coupled receptor 5 (TGR5), and farnesoid X receptor (FXR). These multi-organ interaction networks involving the gut–fat, gut–liver, and gut–brain axes reflect the role of ginseng in integrating systemic metabolism. In summary, this review discusses the multi-level regulatory network through which ginseng promotes WAT browning, providing a mechanistic basis for its potential application in body weight and metabolic health management.

Background: Oxidative stress, induced by the aging process, has been demonstrated to engender a variety of deleterious effects on the organism. The effectiveness of selenium-enriched Rhodotorula mucilaginosa remains unproven. Methods: In this study, selenium-enriched Rhodotorula mucilaginosa JAASRY1 ( Se-RMSRY ) was comprehensively characterized. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy was employed to analyze its morphology and the elemental distribution of selenium. Furthermore, the specific chemical forms of biogenic selenium in Se-RMSRY were identified and quantified using high-performance liquid chromatography-inductively coupled plasma mass spectrometry. The potential of Se-RMSRY to exert antioxidant mechanisms for anti-aging effects was then systematically elucidated. Animal behavioral tests demonstrated behavioral differences induced by Se-RMSRY , thereby evaluating the improvement in aging phenotypes. Histopathological analysis of the hippocampus, liver, and intestine was performed to examine structural integrity and pathological changes. Intracellular reactive oxygen species (ROS) levels were detected using fluorescence-based assays to confirm oxidative stress mitigation. Western blotting was employed to validate the expression of aging-related proteins. Additionally, gut microbiome analysis via 16S rRNA sequencing was carried out to explore the composition and diversity of gut microbiota, thereby uncovering potential links between antioxidant activity and gut health in the anti-aging process. Results: The results showed that selenomethionine (SeMet) was the predominant bioselenium composition of Se-RMSRY , with a concentration of 1213.16 mg/kg. Furthermore, Se-RMSRY significantly enhanced intestinal homeostasis by enriching beneficial Lactobacillus sp. populations and reprogramming microbial metabolism toward carbohydrate utilization while suppressing amino acid metabolism in aging mice ( p < 0.05). Systemic antioxidant capacity was augmented via coordinated activation of the Nrf2/NQO1/HO-1 signaling pathway and glutathione metabolism, with concomitant reductions in hepatic and intestinal oxidative stress markers ( p < 0.05). The intervention attenuated apoptosis through Bcl-2/Bax pathway modulation and improved gut barrier integrity ( p < 0.05), while hippocampal CA1 neuronal preservation correlated with reduced anxiety-like behaviors and enhanced cognitive performance ( p < 0.05). Conclusion: These findings establish Se-RMSRY as a promising dietary intervention against age-related pathologies through gut–microbiota–organ axis regulation, thereby addressing the previously unproven efficacy of Se-RMSRY in counteracting aging-related oxidative stress.

Microbial fermentation is an important means to enhance the nutrition and functionality of food, and soybean fermentation has a long history and a wide variety of products. This study systematically compared the effects of fermentation and post-ripening processes of Bacillus subtilis natto JLCC513 on the nutritional components, active substances, and sensory characteristics of soybeans. The experimental results showed that, in terms of basic nutrition, fermentation led to a significant decrease in fat and reducing sugar content, followed by an initial increase and then a decrease in total protein content. In contrast, water-soluble protein continued to increase, and the total amount of free amino acids surged. The active nutritional indicators before and after soybean fermentation showed that nattokinase activity continued to increase during fermentation and post-ripening. At the same time, the number of viable bacteria decreased slightly during post-ripening. The increase in the proportion of easily absorbed aglycone-type isoflavones before and after soybean fermentation is accompanied by a sustained increase in vitamin K2 and gamma aminobutyric acid (GABA) content. In terms of sensory quality, color-difference analysis shows a decrease in brightness (L value) and an increase in redness (a value), resulting in the characteristic yellow-brown color of natto. In terms of texture characteristics, the hardness decreases, while the viscosity and elasticity are significantly enhanced. Through GC-IMS analysis of volatile aromas during soybean fermentation and post-ripening, it was found that esters (such as ethyl acetate) and pyrazines (such as 2,3-dimethylpyrazine) increased, and the product flavor shifted from grassy to fruity and nutty. In summary, natto bacteria enhance the digestibility, nutritional value, and sensory acceptance of soybeans through enzymatic hydrolysis and metabolic transformation. The post-ripening stage plays a key role in flavor maturation and further accumulation of active ingredients.