Pharmaceutical significance of Leuconostoc mesenteroides KS-TN11 isolated from Nile Tilapia, Oreochromis niloticus

Fermentation of Murta (Ugni molinae) Juice: Effect on Antioxidant Activity and Control of Enzymes Associated with Glucose Assimilation

Berries are rich in bioactive compounds, including antioxidants and especially polyphenols, known inhibitors of starch metabolism enzymes. Lactic acid fermentation of fruits has received considerable attention due to its ability to enhance bioactivity. This study investigated the effect of fermentation with L. mesenteroides of juice from the Chilean berry murta on antioxidant activity, release of polyphenols, and inhibitory activity against α-amylase and α-glucosidase enzymes. Three types of juices (natural fruit, freeze-dried, and commercial) were fermented. Total polyphenol content (Folin-Ciocalteu), antioxidant activity (DPPH and ORAC), and the ability to inhibit α-amylase and α-glucosidase enzymes were determined. Fermented murta juices exhibited increased antioxidant activity, as evidenced by higher levels of polyphenols released during fermentation. Inhibition of α-glucosidase was observed in the three fermented juices, although no inhibition of α-amylase was observed; the juice from freeze-dried murta stood out. These findings highlight the potential health benefits of fermented murta juice, particularly its antioxidant properties and the ability to modulate sugar assimilation by inhibiting α-glucosidase.

Microbial metabolism and health risk assessment of kitchen waste odor VOCs

Kitchen waste (KW) generates odors comprising complex volatile organic compounds (VOCs). We used gas chromatography-mass spectrometry to analyze VOCs, and 16S gene sequencing was used to analyze the microbial community composition and microbial metabolic mechanism. The results showed that the major odor-causing VOCs were hydrogen sulfide, methanethiol, methyl sulfide, dimethyl disulfide, and ethyl acetate. As the temperature increased, the VOCs and microbial community composition became more complex, and the microbial community related to VOC production included Leuconostoc, Pediococcus, Acetobacter, and Weissella. Based on PICRUSt2 analysis, the possibility of typical VOC interconversion by microbial metabolism was low. It was more likely that precursor substances were catalyzed by enzymes to generate the corresponding VOCs. Attention should be given to trichloromethane and 1,2-dichloroethane, which may cause adverse health effects through long-term inhalation. The study results provide guidance for controlling VOCs from KW.

Fermented fish and fermented fish-based products, an ever-growing source of microbial diversity: A literature review

Fermented fish and fermented fish-based products are part of the diet of many countries all over the world. Their popularity is not only due to the unique flavor, the distinct texture, and the good nutritional quality, but also to the easiness of the production process, that is commonly based on empirical traditional methods. Fish fermentation techniques ususally rely on the combination of some key steps, including salting, addition of spices or additives, and maintenance of anaerobic conditions, thus selecting for the multiplication of some pro-technological microorganisms. The objective of the present review was to provide an overview of the current knowledge of the microbial communities occurring in fermented fish and fish-based products. Specific information was collected from scientific publications published from 2000 to 2022 with the aim of generating a comprehensive database. The production of fermented fish and fish-based foods was mostly localized in West African countries, Northern European countries, and Southeast Asian countries. Based on the available literature, the microbial composition of fermented fish and fish-based products was delineated by using viable counting combined with identification of isolates, and culture-independent techniques. The data obtained from viable counting highlighted the occurrence of microbial groups usually associated with food fermentation, namely lactic acid bacteria, staphylococci, Bacillus spp., and yeasts. The identification of isolates combined with culture-independent methods showed that the fermentative process of fish-based products was generally guided by lactobacilli (Lactiplantibacillus plantarum, Latilactobacillus sakei, and Latilactobacillus curvatus) or Tetragenococcus spp. depending on the salt concentration. Among lactic acid bacteria populations, Lactococcus spp., Pediococcus spp., Leuconostoc spp., Weissella spp., Enterococcus spp., Streptococcus spp., and Vagococcus spp. were frequently identified. Staphylococcus spp. and Bacillus spp. confirmed a great adaptation to fermented fish-based products. Other noteworthy bacterial taxa included Micrococcus spp., Pseudomonas spp., Psychrobacter spp., Halanaerobium spp., and Halomonas spp. Among human pathogenic bacteria, the occurrence of Clostridium spp. and Vibrio spp. was documented. As for yeast populations, the predominance of Candida spp., Debaryomyces spp., and Saccharomyces spp. was evidenced. The present literature review could serve as comprehensive database for the scientific community, and as a reference for the food industry in order to formulate tailored starter or adjunctive cultures for product improvement.

In Vitro Evaluation of Leuconostoc mesenteroides Cell-Free-Supernatant GBUT-21 against SARS-CoV-2

The unprecedented health catastrophe derived from the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2 infection) met with a phenomenal scientific response across the globe. Worldwide, the scientific community was focused on finding a cure for the deadly disease. A wide range of research studies has consistently revealed the link between SARS-CoV-2 infection severity and abnormal gut microbiomes, suggesting its potential in developing novel therapeutic approaches. Probiotics have been extensively studied to promote health in human hosts and reestablish a balance in the dysbiotic gut microbiome; however, there is strong skepticism about their safety and efficacy. Consequently, the metabolic signatures of probiotics, often referred to as "postbiotics", could prove of paramount importance for adjuvant cures in patients with SARS-CoV-2. Postbiotics exhibit safety, enhanced shelf-life, and stability and, therefore, could be implemented in SARS-CoV-2 prophylactic strategies with no undue adverse side effects. The current study is a preliminary investigation of the antiviral properties of postbiotic metabolites derived from Leuconostoc mesenteroides GBUT-21. The study focuses on the potential biological role in inactivating SARS-CoV-2 and reducing related inflammatory pathways.

Characterization of New Probiotic Isolates from Fermented Ajwa Dates of Madinah and Their Anti-Inflammatory Potential

A total of 20 Lactobacillus strains isolated from fermented dates were tested for their probiotic potential by comparing their pH stability, resistance to low pH, and ability to tolerate bile salts. Out of 20 strains, 3 strains named as Lactobacillus pentosus KAU001, Lactiplantibacillus pentosus KAU002, and Lactiplantibacillus plantarum KAU003 had a high tolerance of acids and bile salts and the capability to adhere to the intestinal wall. In addition, the three isolates were tested for their anti-oxidation, anti-glucosidase inhibition, cholesterol-lowering, and anti-inflammation properties. Among them, strain KAU001 and KAU002 inhibited α-glucosidase, lowered cholesterol level, inhibited nitric oxide production, and showed a higher anti-oxidative ability that was significantly better than strain KAU003. Both strains also significantly inhibited the release of inflammatory mediators such as TNF-α, IL-6 and IL-10 induced by LPS on RAW 264.7 macrophages (p < 0.001). The results indicated that KAU001 and KAU002 have the highest probiotic potential, potentially modulating metabolic health and reducing pro-inflammatory cytokines in response to allergic reactions.

Potential Antiviral Activity of Lactiplantibacillus plantarum KAU007 against Influenza Virus H1N1

The development of antiviral resistance has exacerbated a growing threat to public health. As a result, there is increasing demand for unconventional antivirals that can effectively replace the presently in-use drugs. Lactic acid-producing bacteria (LAB) are among the most common bacteria used in the food industry. These bacteria play an essential role in the fermentation of many foods and feed. Additionally, these bacteria are considered more economical, efficient, and safe “nutraceuticals” in the health care arsenal. Therefore, we carried out the screening and molecular characterization of raw camel milk LAB isolates and tested their inhibitory activity against influenza virus H1N1. The strain that exhibited the highest antiviral activity against the H1N1 virus, confirmed by hemagglutination assay, was identified as Lactiplantibacillus plantarum KAU007. The study also confirmed the non-cytotoxic behavior of CFCS isolated from KAU007 against MDCK cells, approving its safety concern against the mammalian cells. Besides, CFCS at 5 and 10 mg/mL significantly decreased the level of IFN-γ (p < 0.001 and p < 0.001) and IL-6 (p < 0.001 and p < 0.005) in a dose-dependent manner, respectively. This is a preliminary report about the anti-influenza activity of KAU007 isolated from camel milk. This study reinforces that camel milk contains beneficial LAB isolates with antagonistic properties against the H1N1 influenza virus.