Genetic marker gene, recQ, differentiating Bacillus subtilis and the closely related Bacillus species

Whole genome sequencing of the poly-γ-glutamic acid-producing novel Bacillus subtilis Tamang strain, isolated from spontaneously fermented kinema

Kinema, a traditional fermented soybean food from the Himalayas, is well-liked for its sticky texture and flavourful umami taste. Among 175 bacterial strains from spontaneously fermented kinema samples, Bacillus subtilis Tamang strain stood out for its high stickiness and viscosity. The strain's Poly-γ-glutamic acid (γ-PGA) contains various groups of glutamic acid and has a molecular weight of 660 kDa. It demonstrates the ability to solubilize iron, preserve ferritin in Caco-2 cells, and exhibit antibacterial properties. The genome of B. subtilis Tamang is devoid of plasmid elements but does feature nine insert elements. Noteworthy is the presence of unique secondary metabolites with potential antimicrobial effects, such as amyloliquecidin GF610, bogorol A, and thermoactinoamide A. A total of 132 carbohydrate-active enzymes (CAZy) were identified, hinting at possible prebiotic characteristics. The genome analysis revealed genes responsible for γ-PGA production via the capBCA complex. Furthermore, genes associated with fibrinolytic activity, taste enhancement, biopeptides, immunomodulators, and vitamins like B12 and K2 were found, along with probiotics and various health benefits. The genetic material for L-asparaginase production, known for its anti-cancer properties, was also detected, as well as CRISPR-Cas systems. The absence of virulence factors and antimicrobial resistance genes confirms the safety of consuming B. subtilis Tamang as a food-grade bacterium.

Deficiency in Opu Systems Imparts Salt-Sensitivity to Weizmannia coagulans

Weizmannia coagulans can be used as a starter strain in fermented foods or as a probiotic. However, it is salt-sensitive. Here, W. coagulans genomes were compared with the genomes of strains of Bacillus species (B. licheniformis, B. siamensis, B. subtilis, and B. velezensis) that were isolated from fermented foods and show salt tolerance, to identify the basis for the salt-sensitivity of W. coagulans. Osmoprotectant uptake (Opu) systems transport compatible solutes into cells to help them tolerate osmotic stress. B. siamensis, B. subtilis, and B. velezensis each possess five Opu systems (OpuA, OpuB, OpuC, OpuD, and OpuE); B. licheniformis has all except OpuB. However, W. coagulans only has the OpuC system. Based on these findings, the opuA and opuB operons, and the opuD and opuE genes, were amplified from B. velezensis. Expression of each of these systems, respectively, in W. coagulans increased salt-tolerance. W. coagulans expressing B. velezensis opuA, opuD, or opuE grew in 10.5% NaCl (w/v), whereas wild-type W. coagulans could not grow in 3.5% NaCl. The salt resistance of B. subtilis was also increased by overexpression of B. velezensis opuA, opuB, opuD, or opuE. These results indicate that the salt-susceptibility of W. coagulans arises because it is deficient in Opu systems.

Microbiological evaluation of the indigenous fermented condiment okpeye available at various retail markets in the south-eastern region of Nigeria

In Africa, indigenous fermented condiments contribute to food security as a low-cost source of protein. Okpeye is an indigenous fermented condiment produced from Prosopis africana seeds. The reliance on spontaneous fermentation processes and unhygienic practices during production often results in the contamination of the final product with microbial hazards. A microbiological evaluation of 18 commercial samples of okpeye purchased from six markets in two cities in southeastern Nigeria was conducted. Fifty-nine (59) bacteria were isolated and identified at the species level by phenotyping and sequencing the 16S rRNA, gyrB and rpoB genes. Bacillus (47.4 %) and Staphylococcus (42.3 %) were the predominant bacterial genera in okpeye. Overall, B. amyloliquefaciens and S. simulans were the most frequently occurring bacteria and were present in all samples. In addition, B. cereus was isolated in samples obtained from all markets. Other bacterial species included B. velezensis, Oceanobacillus caeni, S. cohnii, Escherichia fergusonni and Vagacoccus lutrae. The B. cereus isolates (10) were screened for the presence of 8 enterotoxin genes (hblA, hblC, hblD, nheA, nheB, nheC, cytK, entFM) and one emetic gene (cesB). The non-haemolytic enterotoxin (nheABC) and haemolytic enterotoxin (hblABD) complexes were present in 70 % and 50 % of B. cereus respectively. The positive rate of cytK and entFM genes was 70 %, while the cesB gene was 30 %. Antibiotic susceptibility assessment showed that most of the isolates were susceptible to gentamicin, tetracycline, streptomycin, and erythromycin but resistant to ciprofloxacin and vancomycin. These findings highlight the need for further controls to reduce contamination with potential pathogenic bacteria in indigenous fermented condiments such as okpeye. There is also a need to educate producers regarding hygienic practices to safeguard public health and food security.

Draft Genome Sequence of Bacillus velezensis Strain Marseille-Q1230, Isolated from a Stool Sample from a Severely Malnourished Child

Bacillus velezensis, a species first described in 2005, has been mostly associated with plants and the environment. To date, there is no genome available for this species from human samples. In this announcement, we present the genome of Bacillus velezensis strain Marseille-Q1230, which was isolated from a stool sample from a child suffering from severe acute malnutrition. The genome assembled into 15 contigs and had a size of 3,861,152 bp, with a GC content of 46.6%. A total of 3,716 protein-coding genes, including 3 antibiotic resistance genes and 92 RNAs, were predicted.

Current Perspectives on the Physiological Activities of Fermented Soybean-Derived Cheonggukjang

Cheonggukjang (CGJ, fermented soybean paste), a traditional Korean fermented dish, has recently emerged as a functional food that improves blood circulation and intestinal regulation. Considering that excessive consumption of refined salt is associated with increased incidence of gastric cancer, high blood pressure, and stroke in Koreans, consuming CGJ may be desirable, as it can be made without salt, unlike other pastes. Soybeans in CGJ are fermented by Bacillus strains (B. subtilis or B. licheniformis), Lactobacillus spp., Leuconostoc spp., and Enterococcus faecium, which weaken the activity of putrefactive bacteria in the intestines, act as antibacterial agents against pathogens, and facilitate the excretion of harmful substances. Studies on CGJ have either focused on improving product quality or evaluating the bioactive substances contained in CGJ. The fermentation process of CGJ results in the production of enzymes and various physiologically active substances that are not found in raw soybeans, including dietary fiber, phospholipids, isoflavones (e.g., genistein and daidzein), phenolic acids, saponins, trypsin inhibitors, and phytic acids. These components prevent atherosclerosis, oxidative stress-mediated heart disease and inflammation, obesity, diabetes, senile dementia, cancer (e.g., breast and lung), and osteoporosis. They have also been shown to have thrombolytic, blood pressure-lowering, lipid-lowering, antimutagenic, immunostimulatory, anti-allergic, antibacterial, anti-atopic dermatitis, anti-androgenetic alopecia, and anti-asthmatic activities, as well as skin improvement properties. In this review, we examined the physiological activities of CGJ and confirmed its potential as a functional food.