Phosphorus (P) is an essential nutrient for plant growth but the global supply is limited, and over-reliance on chemical phosphate fertilizers can lead to soil pollution and ecological imbalance. Phosphate-solubilizing bacteria (PSB) can convert insoluble P in the soil into plant-available forms and enhance the P utilization efficiency of crops. The application of PSB can also improve the soil ecological environment and contribute to the sustainable development of agriculture. This review systematically summarizes the diversity and distribution of PSB. It comprehensively investigates the mechanisms through which PSB enhance soil P utilization efficiency, focusing on the following aspects: the acid-mediated solubilization of inorganic P, the enzymatic hydrolysis of organic P, the interactions between PSB and plant roots, and the interactions between PSB and rhizosphere microorganisms. Furthermore, recent advances in the development and application of PSB-based biofertilizers are also reviewed. Potential future research directions and the anticipated challenges within this field are also discussed, to develop innovative strategies for alleviating P deficiency in agricultural soils.

With the increasing awareness of health, more people have shown a preference for low-alcohol beverages. Seeking various methods to improve the quality of kiwi wine is now a major research interest in the wine industry. In this study, kiwi wine was fermented by Saccharomyces cerevisiae and different non-Saccharomyces strains (Torulaspora delbrueckii, Kluyveromyces thermotolerans, Pichia fermentans) in three methods (pure fermentation, simultaneous, and sequential co-fermentation). The physicochemical characteristics, color parameters, phenolic profiles, total phenolic content (TPC), antioxidant activities, organic acids, and taste sense of the different wines were evaluated to determine the effects of different yeasts and fermentation methods on the quality of the kiwi wine. Results indicated that co-fermentation reduced the contents of alcohol while enhancing the lightness of the kiwi wine. The TPC of sequential co-fermentation with K. thermotolerans/S. cerevisiae was significantly higher than that of their simultaneous co-fermentation. Compared to K. thermotolerans/S. cerevisiae, the antioxidant activities were increased by co-fermentation of T. delbrueckii/S. cerevisiae and P. fermentans/S. cerevisiae. Principal component analysis showed that kiwi wines fermented by different yeasts and inoculation methods could be separated and grouped. Correlation analysis presented positive correlations of phenolic composition, antioxidant activities, and color intensity. This study provided theoretical guidance for co-fermentation of non-Saccharomyces/S. cerevisiae and accelerated the industrialization process of kiwi wine.

Weizmannia coagulans BC99, a Gram-positive, spore-forming, lactic acid-producing bacterium is renowned for its resilience and health-promoting properties, W. coagulans BC99 survives harsh environments, including high temperatures and gastric acidity, enabling effective delivery to the intestines. The consequences of chronic sleep deprivation (SD) include memory deficits and gastrointestinal dysfunction. In this study, a chronic sleep deprivation cognitive impairment model was established by using a sleep deprivation instrument and W. coagulans BC99 was given by gavage for 4 weeks to explore the mechanism by which BC99 improves cognitive impairment in sleep-deprived mice. BC99 improved cognitive abnormalities in novel object recognition tests induced by chronic sleep deprivation and showed behavior related to spatial memory in the Morris water maze test. W. coagulans BC99 reduced the heart mass index of sleep-deprived mice, increased the sleep-related neurotransmitters 5-HT and DA, decreased corticosterone and norepinephrine, and increased alpha diversity and community similarity. It reduced the abundance of harmful bacteria such as Olsenella, increased the abundance of beneficial bacteria such as Lactobacillus and Bifidobacterium, and promoted the production of short-chain fatty acids (SCFAs). W. coagulans BC99 also inhibits LPS translocation and the elevation of peripheral inflammatory factors by maintaining the integrity of the intestinal barrier and inhibiting the expression of the NLRP3 signaling pathway in the jejunum, thereby inhibiting the NLRP3 inflammasome in the brain of mice and reducing inflammatory factors in the brain, providing a favorable environment for the recovery of cognitive function. The present study confirmed that W. coagulans BC99 ameliorated cognitive impairment in chronic sleep-deprived mice by improving gut microbiota, especially by promoting SCFAs production and inhibiting the NLRP3 signaling pathway in the jejunum and brain. These findings may help guide the treatment of insomnia or other sleep disorders through dietary strategies.

Acute alcoholic liver injury (AALI) remains a significant global health concern, primarily driven by oxidative stress. This study investigated the protective mechanisms of Weizmannia coagulans BC99 against alcohol-induced oxidative stress using a dual model in rats and Caenorhabditis elegans. In rats, excessive alcohol was predominantly metabolized via the CYP2E1 pathway, leading to severe oxidative stress. However, intervention with BC99 suppressed CYP2E1 expression and enhanced antioxidant enzyme activities through the Nrf2/SKN-1 pathway, thereby alleviating oxidative stress. Additionally, BC99 treatment elevated glutamate and aspartate levels while reducing glycerate and glucose, which collectively increased glutathione levels and mitigated oxidative stress triggered by glucose metabolism disorders. In C. elegans, BC99 reduced excessive ROS by upregulating Nrf2/skn-1, daf-16, and their downstream antioxidant genes, consequently alleviating the biotoxicity associated with alcohol-induced oxidative damage. The protective effects of BC99 were markedly diminished in the skn-1 mutant (GR2245) and daf-16 mutant (CF1038), further confirming the pivotal roles of SKN-1 and DAF-16 pathways in BC99-mediated antioxidant protection. Taken together, these findings reveal that BC99 mitigates alcohol-induced oxidative stress by activating the Nrf2/SKN-1 pathway and regulating liver metabolites to eliminate excess ROS, thereby providing a theoretical basis for the application of probiotics in preventing acute alcoholic liver injury.

Adequate protein consumption is essential for optimal physical fitness and enhancing athletic performance. This study explored the impact of Weizmannia coagulans BC99 on protein-supplemented male fatigued mice, examining aspects such as protein digestion, exercise endurance, fatigue-related biochemistry, oxidative stress, and gut microbiota alterations. Results indicate that the synergistic effect of probiotics and protein significantly boosts the activity of protein-digesting enzymes, enhances protein absorption, and reduces serum levels of urea nitrogen, lactate, lactate dehydrogenase, creatine kinase, malondialdehyde, and the inflammatory cytokines interleukin-1β and interleukin-6 in skeletal muscle. Additionally, serum catalase, glutathione, superoxide dismutase levels, interleukin-4 in skeletal muscle, and glycogen stores in muscle and liver were notably increased. The study also found elevated mRNA expression levels of Nrf2 and HO-1 in skeletal muscle. Furthermore, an increase in short-chain fatty acids was observed in the probiotic treatment group, and 16S rDNA sequencing revealed that Weizmannia coagulans BC99 enhanced gut microbiota diversity and augmented beneficial bacterial populations including Roseburia, Mucispirillum, Rikenella, and Kineothrix. Collectively, these findings suggest that combining BC99 with protein supplementation can effectively improve gut flora, thereby enhancing exercise capacity and exerting potent anti-fatigue effects. Our research provides a new possibility for alleviating exercise-induced fatigue.

The increased emission and accumulation of microplastics pose a severe threat to humans and the environment. As effective biological agents for alleviating the effects of microplastics, the mechanism of action of probiotics remains unclear. In this study, based on the successful establishment of a reproductive virulence model of Caenorhabditis elegans (C. elegans), we explored the effect and mechanism of Weizmannia coagulans CGMCC 9951 (W. coagulans CGMCC 9951) on the reproductive toxicity of C. elegans. Our results showed that the gonad area and the number of offspring increased but the number of germ cells undergoing apoptosis decreased by 14% and 24% in C. elegans, after CGMCC 9951 treatments. Antioxidant test results showed that CGMCC 9951 increased the activity of Superoxide Dismutase (SOD), Catalase (CAT), and the content of Glutathione (GSH) in C. elegans. In addition, it was found by qPCR and mutagenesis experiments verified that CGMCC 9951 alleviated reproductive toxicity through the DNA checkpoint signaling pathway. Our findings suggested that CGMCC 9951 could alleviate the reproductive toxicity of polystyrene microplastics in C. elegans by enhancing antioxidant capacity and inhibiting DNA damage checkpoint signaling pathway. The above results suggest that probiotics can be used as a potential approach to alleviate the reproductive toxicity induced by polystyrene microplastics in humans.