Screening, Characterization, and Identification of Microbial Probiotic Extracts From Wastewater Treatments Plants Using 16S rDNA Sequencing

The performance of probiotic microorganisms is strongly affected by their environment. Bile and pH are crucial properties of the probiotic as they arbitrate the ability of the bacteria to survive in the intestine. It was, therefore, important to assess the tolerance of the abovementioned factors when screening microorganisms for their probiotic potential. This study is aimed at identifying and characterizing probiotic bacteria strains isolated from wastewater treatment plants in South Africa. This study presents the very first extraction of probiotic extracted from wastewater using Lowenstein Jensen agar in South Africa. The isolates were identified and screened using cell morphology SEM, rDNA sequencing, pH and bile salt resistance test, cell surface hydrophobicity, autoaggregation, antimicrobial activity, and antibiotic assay. The 16S rDNA sequencing confirmed the bacterial strains to be Lactiplantibacillus plantarum spp., Lactobacillus paracasei , Bacillus subtilis spp., Bacillus cereus , Enterococcus faecium , Enterococcus faecalis , Enterococcus durans , Pediococcus acidilactici , and Aneurinibacillus aneurinilyticus . The morphologies of bacteria on SEM were mostly rods as suggested by the literature. Among the 10 isolates, nine showed high sensitivity of chloramphenicol, penicillin, gentamicin, streptomycin, erythromycin, ampicillin, vancomycin, tetracycline, and kanamycin antibiotics. The isolates also had moderate sensitivity towards acid resistance, high bile tolerance, and moderate autoaggregation, as well as good solvent adhesion. Probiotic bacteria strains were successfully extracted from wastewater through culturing and then successfully identified by 16S rDNA sequencing. The strains are lucrative microbial resources which could be potentially utilized for the development of pharmaceuticals and food preservatives and for wastewater recycling purposes.