Background The involvement of probiotic cultures in food fermentation guarantees enhanced organoleptic properties and maximum consumer health benefits. In this study, isolated Bacillus cultures used in the fermentation of African locust bean seeds “Parkia biglobosa” into the food condiment “daddawa” were evaluated for probiotic attributes. Bacillus cereus strains BC1 and BC2 were tested for tolerance to acid, common salt (NaCl), and bile salt. Auto-aggregation and adhesion to epithelial cells, antibiotic sensitivity profile, hemolytic pattern, and antibacterial activity were also evaluated. To demonstrate further health benefit, spores of strain BC1 were investigated for anti-inflammatory potential employing the rat paw edema technique. Results Both Bacillus cereus strains showed antagonistic activity against pathogenic Escherichia coli and Staphylococcus aureus. BC1 was more acid-stress tolerant than BC2, maintaining 107.6% viability after 3 h incubation in MRS broth of pH 2.5. However, at 97.74% viability after incubation for 3 h, BC2 was more tolerant to 0.4 % bile salt. The Bacillus cereus strains were susceptible to all antibiotics tested with the exception of norfloxacin and thrived under high saline stress. Both strains were protease producers and non-hemolytic on sheep blood agar. The edema inhibition study revealed that spores of Bacillus cereus strain BC1 had anti-inflammation potential and produced no physiological toxicity on the animals. Conclusion These results indicate that the Bacillus cultures for “daddawa” production are good candidates for probiotics and have the potential for application in both animal and human formulations for increased health benefit to consumers.

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Bacteria remodel their plasma membrane lipidome to maintain key biophysical attributes in response to ecological disturbances. For Halanaerobium and other anaerobic halotolerant taxa that persist in hydraulically fractured deep subsurface shale reservoirs, salinity, and hydraulic retention time (HRT) are important perturbants of cell membrane structure, yet their effects remain poorly understood. Membrane-linked activities underlie in situ microbial growth kinetics and physiologies which drive biogeochemical reactions in engineered subsurface systems. Hence, we used gas chromatography–mass spectrometry (GC–MS) to investigate the effects of salinity and HRT on the phospholipid fatty acid composition of H. congolense WG10 and mixed enrichment cultures from hydraulically fractured shale wells. We also coupled acyl chain remodeling to membrane mechanics by measuring bilayer elasticity using atomic force microscopy (AFM). For these experiments, cultures were grown in a chemostat vessel operated in continuous flow mode under strict anoxia and constant stirring. Our findings show that salinity and HRT induce significant changes in membrane fatty acid chemistry of H. congolense WG10 in distinct and complementary ways. Notably, under nonoptimal salt concentrations (7% and 20% NaCl), H. congolense WG10 elevates the portion of polyunsaturated fatty acids (PUFAs) in its membrane, and this results in an apparent increase in fluidity (homeoviscous adaptation principle) and thickness. Double bond index (DBI) and mean chain length (MCL) were used as proxies for membrane fluidity and thickness, respectively. These results provide new insight into our understanding of how environmental and engineered factors might disrupt the physical and biogeochemical equilibria of fractured shale by inducing physiologically relevant changes in the membrane fatty acid chemistry of persistent microbial taxa.GRAPHICAL ABSTRACTSalinity significantly alters membrane bilayer fluidity and thickness in Halanaerobium congolense WG10.

The abilities of three species of freshwater microalgae to grow in, and desalinate untreated and undiluted seawater were investigated. The salinities of the seawater were reduced from 37.5g/L to 26.25 ± 1.33, 27.19 ± 1.33 and 30.0 ± 0.00 g/L by Desmodesmus subspicatus LC172266, Desmodesmus armatus LC172263 and Dictyosphaerium spp. LC172264 on the fourth, eighth and tenth week of the experiment, respectively, while the control had no change in the salinity. D. subspicatus cell concentration initially dropped from 1.25 × 106 cells/ml to 9.68 × 105 cells/ml and then gradually increased to 4.86 × 107 cells/ml by the tenth week. With D. armatus and Dictyosphaerium spp., the cell concentrations increased steadily from 1.25 × 106 cells/ml to 4.97 × 108 cells/ml and 3.25 × 108 cells/ml, respectively. There were increases in the pH during desalination by the three species. This demonstrates the halotolerant potentials of these species and their abilities to reduce the salinity of seawater.