A review on enzyme-producing lactobacilli associated with the human digestive process: From metabolism to application

Microbiome's Universe: Impact on health, disease and cancer treatment

The human microbiome is a diverse ecosystem of microorganisms that reside in the body and influence various aspects of health and well-being. Recent advances in sequencing technology have brought to light microbial communities in organs and tissues that were previously considered sterile. The gut microbiota plays an important role in host physiology, including metabolic functions and immune modulation. Disruptions in the balance of the microbiome, known as dysbiosis, have been linked to diseases such as cancer, inflammatory bowel disease and metabolic disorders. In addition, the administration of antibiotics can lead to dysbiosis by disrupting the structure and function of the gut microbial community. Targeting strategies are the key to rebalancing the microbiome and fighting disease, including cancer, through interventions such as probiotics, fecal microbiota transplantation (FMT), and bacteria-based therapies. Future research must focus on understanding the complex interactions between diet, the microbiome and cancer in order to optimize personalized interventions. Multidisciplinary collaborations are essential if we are going to translate microbiome research into clinical practice. This will revolutionize approaches to cancer prevention and treatment.

Freshwater microalgae Nannochloropsis limnetica for the production of β-galactosidase from whey powder

This study investigated the first-ever reported use of freshwater Nannochloropsis for the bioremediation of dairy processing side streams and co-generation of valuable products, such as β-galactosidase enzyme. In this study, N. limnetica was found to grow rapidly on both autoclaved and non-autoclaved whey-powder media (referred to dairy processing by-product or DPBP) without the need of salinity adjustment or nutrient additions, achieving a biomass concentration of 1.05-1.36 g L-1 after 8 days. The species secreted extracellular β-galactosidase (up to 40.84 ± 0.23 U L-1) in order to hydrolyse lactose in DPBP media into monosaccharides prior to absorption into biomass, demonstrating a mixotrophic pathway for lactose assimilation. The species was highly effective as a bioremediation agent, being able to remove > 80% of total nitrogen and phosphate in the DPBP medium within two days across all cultures. Population analysis using flow cytometry and multi-channel/multi-staining methods revealed that the culture grown on non-autoclaved medium contained a high initial bacterial load, comprising both contaminating bacteria in the medium and phycosphere bacteria associated with the microalgae. In both autoclaved and non-autoclaved DPBP media, Nannochloropsis cells were able to establish a stable microalgae-bacteria interaction, suppressing bacterial takeover and emerging as dominant population (53-80% of total cells) in the cultures. The extent of microalgal dominance, however, was less prominent in the non-autoclaved media. High initial bacterial loads in these cultures had mixed effects on microalgal performance, promoting β-galactosidase synthesis on the one hand while competing for nutrients and retarding microalgal growth on the other. These results alluded to the need of effective pre-treatment step to manage bacterial population in microalgal cultures on DPBP. Overall, N. limnetica cultures displayed competitive β-galactosidase productivity and propensity for efficient nutrient removal on DPBP medium, demonstrating their promising nature for use in the valorisation of dairy side streams.

Postbiotics as Metabolites and Their Biotherapeutic Potential

This review highlights the role of postbiotics, which may provide an underappreciated avenue doe promising therapeutic alternatives. The discovery of natural compounds obtained from microorganisms needs to be investigated in the future in terms of their effects on various metabolic disorders and molecular pathways, as well as modulation of the immune system and intestinal microbiota in children and adults. However, further studies and efforts are needed to evaluate and describe new postbiotics. This review provides available knowledge that may assist future research in identifying new postbiotics and uncovering additional mechanisms to combat metabolic diseases.

Limosilactobacillus reuteri HCS02-001 Attenuates Hyperuricemia through Gut Microbiota-Dependent Regulation of Uric Acid Biosynthesis and Excretion

Hyperuricemia is a prevalent metabolic disorder that arises from abnormal purine metabolism and reduced excretion of uric acid (UA). The gut microbiota plays a significant role in the biosynthesis and excretion of UA. Probiotics capable of purine degradation possess the potential to prevent hyperuricemia. Our study aimed to screen probiotics in areas with abundant dairy products and longevity populations in China, which could attenuate the level of UA and explore the underlying mechanism. In this study, twenty-three lactic acid bacteria isolated from healthy Chinese infant feces and traditional fermented foods such as hurood and lump milk were evaluated for the ability to tolerance acid, bile, artificial gastric juice, and artificial intestinal juice to determine the potential of the candidate strains as probiotics. Eight strains were identified as possessing superior tolerance to simulated intestinal conditions and were further analyzed by high-performance liquid chromatography (HPLC), revealing that Limosilactobacillus reuteri HCS02-001 (Lact-1) and Lacticaseibacillus paracasei HCS17-040 (Lact-2) possess the most potent ability to degrade purine nucleosides. The effect of Lact-1 and Lact-2 on hyperuricemia was evaluated by intervening with them in the potassium oxonate and adenine-induced hyperuricemia Balb/c mice model in vivo. Our results showed that the level of serum UA in hyperuricemic mice can be efficiently reduced via the oral administration of Lact-1 (p < 0.05). It significantly inhibited the levels of liver inflammatory cytokines and hepatic xanthine oxidase through a TLR4/MyD88/NF-κB pathway across the gut-liver axis. Furthermore, UA transporters ABCG2 and SLC2A9 were substantially upregulated by the intervention of this probiotic. Fecal ATP levels were significantly induced, while fecal xanthine dehydrogenase and allantoinase levels were increased following probiotics. RNA sequencing of HT-29 cells line treated with Lact-1 and its metabolites demonstrated significant regulation of pathways related to hyperuricemia. In summary, these findings demonstrate that Limosilactobacillus reuteri HCS02-001 possesses a capacity to ameliorate hyperuricemia by inhibiting UA biosynthesis via enhancing gastrointestinal barrier functions and promoting UA removal through the upregulation of urate transporters, thereby providing a basis for the probiotic formulation by targeting the gut microbiota.

Environmental Evaluation on Toxicity, Toxic Mechanism, and Hydrolysis Behavior of Potential Acethydrazide Fungicide Candidates

The evaluation of toxicity and environmental behavior of bioactive lead molecules is helpful in providing theoretical support for the development of agrochemicals, in line with the sustainable development of the ecological environment. In previous work, some acethydrazide structures have been demonstrated to exhibit excellent and broad-spectrum fungicidal activity; however, its environmental compatibility needs to be further elucidated if it is to be identified as a potential fungicide. In this project, the toxicity of fungicidal acethydrazide lead compounds F51, F58, F72, and F75 to zebrafish was determined at 10 μg mL-1 and 1 μg mL-1. Subsequently, the toxic mechanism of compound F58 was preliminarily explored by histologic section and TEM observations, which revealed that the gallbladder volume of common carp treated with compound F58 increased, accompanied by a deepened bile color, damaged plasma membrane, and atrophied mitochondria in gallbladder cells. Approximately, F58-treated hepatocytes exhibited cytoplasmic heterogeneity, with partial cellular vacuolation and mitochondrial membrane rupture. Metabolomics analysis further indicated that differential metabolites were enriched in the bile formation-associated steroid biosynthesis, primary bile acid biosynthesis, and taurine and hypotaurine metabolism pathways, as well as in the membrane function-related glycerophospholipid metabolism, linolenic acid metabolism, α-linolenic acid metabolism, and arachidonic acid metabolism pathways, suggesting that the acethydrazide F58 may have acute liver toxicity to common carp. Finally, the hydrolysis dynamics of F58 was investigated, with the obtained half-life of 5.82 days. The above results provide important guiding significance for the development of new green fungicides.

Supplementation of Bacillus subtilis and Lactobacillus casei to increase growth performance and immune system of catfish (Clarias gariepinus) due to Aeromonas hydrophila infection

Background and Aim

Catfish has a high economic value and is popular among consumers. To ensure well-stocked catfish stocks, good fisheries management must also be ensured. The high demand for catfish must be supplemented by preventive measures against pathogenic bacterial infections using probiotics with high potential for Lactobacillus casei and Bacillus subtilis. The aim of this study was to determine the effect of probiotic supplementation consisting of a combination of L. casei and B. subtilis probiotics on the growth, immune system, water quality, proximate value of feed, and body composition of catfish infected with Aeromonas hydrophila.

Materials and Methods

This study used a completely randomized study with eight treatments and three replications. The manipulated factor was the probiotic concentration [0% (A), 0.5% (B), 10% (C), and 15% (D)] in groups of catfish infected and uninfected with A. hydrophila. Combination of B. subtilis, and L. casei that were used in a 1:1 ratio of 108 colony forming unit/mL. The study lasted for 42 days. On the 35th day, A. hydrophila was infected by intramuscular injection into fish. The Statistical Package for the Social Sciences (SPSS) software version 23.0 (IBM SPSS Statistics) was used to analyze data on growth, immune system, and water quality.

Results

Providing probiotics in feed can increase the nutritional value of feed based on proximate test results. There were significant differences in average daily gain (ADG), feed conversion ratio (FCR), and survival rate (SR) parameters in the group of catfish infected with A. hydrophila (p > 0.05); however, there were no significant differences in final body weight, specific growth rate (SGR), and percentage weight gain. Interleukin-1β (IL-1β) levels were significantly different between treatments C and D. The tumor necrosis factor (TNF) α parameters were significantly different between treatments A and C, whereas the phagocytic activity of treatment A was significantly different from that of treatment D. There was a significant difference (p > 0.05) in the growth parameters of SGR, ADG, and FCR in the group of fish that were not infected with A. hydrophila, with the best treatment being a probiotic concentration of 15%, but there was no significant difference in the SR parameters. IL-1β and TNF-α levels significantly differed between E and E0 (15% probiotics) but were not significantly different in terms of phagocytosis parameters.

Conclusion

Based on the results of this study, it can be concluded that using a combination of probiotics L. casei and B. subtilis can improve the growth, immune system, water quality, proximate value of feed, and body composition of catfish infected with A. hydrophila.

Effects of in vitro fermentation of Atractylodes chinensis (DC.) Koidz. polysaccharide on fecal microbiota and metabolites in patients with type 2 diabetes mellitus

Atractylodes chinensis (DC.) Koidz. polysaccharide (AKP) has been shown to have hypoglycemic activity. In this study, the effects of AKP on fecal microbiota and metabolites in healthy subjects and patients with type 2 diabetes mellitus (T2DM) were investigated using an in vitro simulated digestive fermentation model. AKP were isolated and purified from Atractylodes chinensis (DC.) Koidz. Its main component AKP1 (AKP-0 M, about 78 % of AKP) has an average molecular weight of 3.25 kDa with monosaccharide composition of rhamnose, arabinose, and galactosamine in a molar ratio of 1: 1.25: 2.88. Notably, AKP fermentation might improve the intestinal microbiota of T2DM patients by the enrichment of some specific bacteria rather than the increase of microbial diversity. The addition of AKP specifically enriched Bifidobacteriaceae and weakened the proportion of Escherichia-Shigella. Moreover, AKP also increased the levels of short-chain fatty acids without affecting total gut gas production, suggesting that AKP could have beneficial effects while avoiding flatulence. Metabolomic analysis revealed that ARP fermentation caused changes in some metabolites, which were mainly related to energy metabolism and amino acid metabolism. Importantly, ARP fermentation significantly increased the level of myo-inositol, an insulin sensitizer. In addition, a significant correlation was observed between specific microbiota and differential metabolites. This study has laid a theoretical foundation for AKP application in functional foods.

Draft genome sequence and probiotic functional property analysis of Lactobacillus gasseri LM1065 for food industry applications

Probiotics are defined as live organisms in the host that contribute to health benefits. Lactobacillus gasseri LM1065, isolated from human breast milk, was investigated for its probiotic properties based on its genome. Draft genome map and de novo assembly were performed using the PacBio RS II system and hierarchical genome assembly process (HGAP). Probiotic properties were determined by the resistance to gastric conditions, adherence ability, enzyme production, safety assessment and mobile genetic elements. The fungistatic effect and inhibition of hyphae transition were studied using the cell-free supernatant (CFS). L. gasseri LM1065 showed high gastric pepsin tolerance and mild tolerance to bile salts. Auto-aggregation and hydrophobicity were measured to be 61.21% and 61.55%, respectively. The adherence to the human intestinal epithelial cells was measured to be 2.02%. Antibiotic-resistance genes and putative virulence genes were not predicted in the genomic analysis, and antibiotic susceptibility was satisfied by the criteria of the European Food Safety Authority. CFS showed a fungistatic effect and suppressed the tricarboxylic acid cycle in Candida albicans (29.02%). CFS also inhibited the transition to true hyphae and damaged the blastoconidia. This study demonstrates the essential properties of this novel probiotic, L. gasseri LM1065, and potential to inhibit vaginal C. albicans infection.

Postbiotics as potential new therapeutic agents for sepsis

Sepsis is the main cause of death in critically ill patients and gut microbiota dysbiosis plays a crucial role in sepsis. On the one hand, sepsis leads to the destruction of gut microbiota and induces and aggravates terminal organ dysfunction. On the other hand, the activation of pathogenic gut flora and the reduction in beneficial microbial products increase the susceptibility of the host to sepsis. Although probiotics or fecal microbiota transplantation preserve gut barrier function on multiple levels, their efficacy in sepsis with intestinal microbiota disruptions remains uncertain. Postbiotics consist of inactivated microbial cells or cell components. They possess antimicrobial, immunomodulatory, antioxidant and antiproliferative activities. Microbiota-targeted therapy strategies, such as postbiotics, may reduce the incidence of sepsis and improve the prognosis of patients with sepsis by regulating gut microbial metabolites, improving intestinal barrier integrity and changing the composition of the gut microbiota. They offer a variety of mechanisms and might even be superior to more conventional 'biotics' such as probiotics and prebiotics. In this review, we present an overview of the concept of postbiotics and summarize what is currently known about postbiotics and their prospective utility in sepsis therapy. Overall, postbiotics show promise as a viable adjunctive therapy option for sepsis.

Exploring the Cholesterol-Modifying Abilities of Lactobacilli Cells in Digestive Models and Dairy Products

This study aimed to investigate the ability of lactic acid bacteria to remove cholesterol in simulated gastric and intestinal fluids. The findings showed that the amount of cholesterol removed was dependent on the biomass, viability, and bacterial strain. Some cholesterol binding was stable and not released during gastrointestinal transit. The presence of cholesterol affected the fatty acid profile of bacterial cells, potentially influencing their metabolism and functioning. However, adding cholesterol did not significantly impact the survival of lactic acid bacteria during gastrointestinal transit. Storage time, passage, and bacterial culture type did not show significant effects on cholesterol content in fermented dairy products. Variations in cell survival were observed among lactic acid bacteria strains in simulated gastric and intestinal fluids, depending on the environment. Higher milk protein content was found to be more protective for bacterial cells during gastrointestinal transit than fat content. Future research should aim to better understand the impact of cholesterol on lactic acid bacteria metabolism and identify potential health benefits.

Exploring the Core Microbiota of Four Different Traditional Fermented Beverages from the Colombian Andes

Fermentation is an ancient process used to prepare and preserve food. Currently, fermented beverages are part of the culture of people living in the Colombian Andean Region, and they are a vital part of their cosmology and ancestral vision. Chicha, Forcha, Champús, and Masato are some of the most common Colombian Andes region’s traditional fermented beverages. These drinks come from the fermentation of maize (Zea maize), but other cereals such as wheat or rye, could be used. The fermentation is carried out by a set of bacteria and yeasts that provide characteristic organoleptic properties of each beverage. In this work, the information collected from the metagenomics analyses by sequencing ITS 1-4 (Internal Transcriber Spacer) and the 16S ribosomal gene for fungi and the V3-V4 region of the rDNA for bacteria allowed us to identify the diversity present in these autochthonous fermented beverages made with maize. The sequencing analysis showed the presence of 39 bacterial and 20 fungal genera. In addition, we determined that only nine genera of bacteria and two genera of fungi affect the organoleptic properties of smell, colour, and flavour, given the production of compounds such as lactic acid, alcohol, and phenols, highlighting the critical role of these microorganisms. Our findings provide new insights into the core microbiota of these beverages, represented by Lactobacillus fermentum, Acetobacter pasteurianus, and Saccharomyces cerevisiae.

The Gut Microbiome and Its Implication in the Mucosal Digestive Disorders

The gastrointestinal (GI) tract is one of the most studied compartments of the human body as it hosts the largest microbial community including trillions of germs. The relationship between the human and its associated flora is complex, as the microbiome plays an important role in nutrition, metabolism and immune function. With a dynamic composition, influenced by many intrinsic and extrinsic factors, there is an equilibrium maintained in the composition of GI microbiota, translated as "eubiosis". Any disruption of the microbiota leads to the development of different local and systemic diseases. This article reviews the human GI microbiome's composition and function in healthy individuals as well as its involvement in the pathogenesis of different digestive disorders. It also highlights the possibility to consider flora manipulation a therapeutic option when treating GI diseases.

Current advances and research prospects for agricultural and industrial uses of microbial strains available in world collections

Microorganisms are an important component of the ecosystem and have an enormous impact on human lives. Moreover, microorganisms are considered to have desirable effects on other co-existing species in a variety of habitats, such as agriculture and industries. In this way, they also have enormous environmental applications. Hence, collections of microorganisms with specific traits are a crucial step in developing new technologies to harness the microbial potential. Microbial culture collections (MCCs) are a repository for the preservation of a large variety of microbial species distributed throughout the world. In this context, culture collections (CCs) and microbial biological resource centres (mBRCs) are vital for the safeguarding and circulation of biological resources, as well as for the progress of the life sciences. Ex situ conservation of microorganisms tagged with specific traits in the collections is the crucial step in developing new technologies to harness their potential. Type strains are mainly used in taxonomic study, whereas reference strains are used for agricultural, biotechnological, pharmaceutical research and commercial work. Despite the tremendous potential in microbiological research, little effort has been made in the true sense to harness the potential of conserved microorganisms. This review highlights (1) the importance of available global microbial collections for man and (2) the use of these resources in different research and applications in agriculture, biotechnology, and industry. In addition, an extensive literature survey was carried out on preserved microorganisms from different collection centres using the Web of Science (WoS) and SCOPUS. This review also emphasizes knowledge gaps and future perspectives. Finally, this study provides a critical analysis of the current and future roles of microorganisms available in culture collections for different sustainable agricultural and industrial applications. This work highlights target-specific potential microbial strains that have multiple important metabolic and genetic traits for future research and use.

Role of Postbiotics in Diet-Induced Metabolic Disorders

Although the prevalence of metabolic disorders has progressively increased over the past few decades, metabolic disorders can only be effectively treated with calorie restriction and improved physical activity. Recent research has focused on altering the gut microbiome using prebiotics, probiotics, and postbiotics because various metabolic syndromes are caused by gut microbial dysbiosis. Postbiotics, substances produced or released by microorganism metabolic activities, play an important role in maintaining and restoring host health. Because postbiotics have a small amount of literature on their consumption, there is a need for more experiments on short- and long-term intake. This review discusses current postbiotic research, categories of postbiotics, positive roles in metabolic syndromes, and potential therapeutic applications. It covers postbiotic pleiotropic benefits, such as anti-obesity, anti-diabetic, and anti-hypertensive qualities, that could aid in the management of metabolic disorders. Postbiotics are promising tools for developing health benefits and therapeutic goals owing to their clinical, technical, and economic properties. Postbiotic use is attractive for altering the microbiota; however, further studies are needed to determine efficacy and safety.