Spore-forming Bacillus species are gaining interest in human health recently, due to their ability to withstand the harsh environment of the gastrointestinal tract. The present study explores probiotic features of Bacillus paranthracis strain MHSD3 through genomic analysis and in vitro probiotic assays. The draft genome of strain MHSD3 contained genes associated with tolerance to gastrointestinal stress and adhesion. Cluster genes responsible for the synthesis of antimicrobial non-ribosomal peptide synthetases, bacteriocins, and linear azole-containing peptides were identified. Additionally, strain MHSD3 was able to survive in an acidic environment, had the tolerance to bile salt, and exhibited the capability to tolerate gastric juices. Moreover, the isolate was found to possess strong cell surface traits such as high auto-aggregation and hydrophobicity indices of 79 and 54%, respectively. Gas chromatography–mass spectrometry analysis showed that the strain produced secondary metabolites such as amino acids, phenolic compounds, and organic acid, known to exert health-promoting properties, including the improvement of gastrointestinal tract health.

Microbial symbioses deal with the symbiotic interactions between a given microorganism and another host. The most widely known and investigated microbial symbiosis is the association between leguminous plants and nitrogen-fixing rhizobia. It is one of the best-studied plant–microbe interactions that occur in the soil rhizosphere and one of the oldest plant–microbe interactions extensively studied for the past several decades globally. Until recently, it used to be a common understanding among scientists in the field of rhizobia and microbial ecology that the root nodules of thousands of leguminous species only contain nitrogen-fixing symbiotic rhizobia. With the advancement of molecular microbiology and the coming into being of state-of-the-art biotechnology innovations, including next-generation sequencing, it has now been revealed that rhizobia living in the root nodules of legumes are not alone. Microbiome studies such as metagenomics of the root nodule microbial community showed that, in addition to symbiotic rhizobia, other bacteria referred to as non-rhizobial endophytes (NREs) exist in the nodules. This review provides an insight into the occurrence of non-rhizobial endophytes in the root nodules of several legume species and the beneficial roles of the tripartite interactions between the legumes, the rhizobia and the non-rhizobial endophytes (NREs).

Although intense research has gone into the exploration of various Combretaceae species towards the discovery of therapeutic relevant compounds, their endophytes have never been explored as potential repositories of alternative sources of novel and medically beneficial equivalents. In the present study, five bacterial endophytes (Lysinibacillus, Staphylococcus, Enterobacter, Pseudomonas and Bacillus species) were isolated from different parts (hard stem, leaves and soft stem) of Combretum molle and identified to species level using morphological data and sequencing of the 16S rRNA. Four of the five endophytes showed varying degrees of antimicrobial characteristics against Bacillus cereus, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Key words: Bacterial endophytes, bioactive compounds, Combretum molle, phylogenetic analysis, medicinal plant.

The digestive process and intestinal protein absorption are influenced by a variety of factors. Due to their numerous health advantages, including potential favorable effects on protein digestion and absorption, probiotics have gained increased attention in recent years. Probiotics can control the intestinal microflora, which in turn affects the intestinal bacteria responsible for proteolysis. Additionally, certain probiotics can release exoenzymes that aid in the digestion of proteins and others can stimulate the host’s digestive protease and peptidase activity. By boosting transport and enhancing the epithelium’s capacity for absorption, probiotics can also improve the absorption of tiny peptides and amino acids as well as lessen detrimental protein fermentation, which lowers the toxicity of metabolites. The present study explored the production of enzymes by Bacillus paranthracis strain MHDS3, a probiotic candidate isolated from Pellaea calomelanos. Bacillus paranthracis displayed enzyme activities of amylase (31,788.59 IU), cellulase (4487.486 IU), and pectinase (13.98986 IU) through submerged fermentation. The CAZyme analysis of B. paranthracis revealed 16 CAZyme gene clusters associated with cellulose, amylase, and pectinase activity. Thus, B. paranthracis is a promising probiotic strain that can produce enzymes with biotechnological applications.

Prolonged inoculation of soya bean (Glycine max L.) farms with exotic strains of Bradyrhizobium species starting in the 1960s resulted in the establishment of populations of Bradyrhizobium strains in the soils of several soya bean farms in South Africa. With the increasing number of new soya bean genotypes in the country, it is challenging to determine which genotypes are highly compatible with a given rhizobium strain. In this study, we investigated the symbiotic compatibility of native rhizobial isolates and the strains from the South African Rhizobium Culture Collection (SARCC) on ten selected locally available soya bean genotypes. A glasshouse soil trap experiment using soil samples collected from Lothair, Bothaville, and Standerton was performed on five cultivars. The trapped rhizobial strains were further screened in the glasshouse to authenticate their nodulation compatibility with the different soya bean cultivars. The rhizobial strains showed significant nodulation compatibility with the selected cultivars. These strains were also tested for beneficial traits in vitro and characterized using DNA sequencing methods to elucidate their taxonomic identity. Some of the most nodulation-compatible strains characterized as Bradyrhizobium and Sinorhizobium species exhibited significant symbiotic performance in terms of plant biomass, nodule number, and nodule dry weight. The study generated valuable data that provide information on the extent of symbiotic compatibility of some of the existing cultivars used in South Africa with native rhizobia and whether inoculation of soya bean with commercial products is vital on some soya bean farms.