PROBIOTIC CHARACTERIZATION OF BACILLUS SUBTILIS STRAIN ISOLATED FROM INFANT FECAL MATTER REVEALED BY 16S rRNA GENE AND PHYLOGENETIC ANALYSIS

Objective: The rationale of our study was to isolate and identify the putative probiotic strain from infant fecal matter exhibiting a broad range of antimicrobial activity and to analyze the effect of different culturing conditions on its probiotic properties and the production of antimicrobial metabolites. Methods: In the present study, bacterial strains were screened for probiotic properties and antimicrobial activity from infant fecal matter (6 months–2 years). The effect of varying culture conditions such as tolerance to acid, bile salt, phenol, NaCl, pH, incubation period, and temperature along with autoaggregation assay, hydrophobicity, and hemolysis was studied. The characterization of the potent strain was studied by morphological, biochemical, and 16S rRNA gene sequencing along the phylogenetic affiliation of the strain was studied. Results: Two putative probiotic bacteria (DAM and IFM) were isolated, identified, characterized, and predicted at pH 2.0, 3.0, and 4.0, the isolate IFM had 50%, 60%, and 70% survivability, while isolate DAM had 55%, 63%, and 75% survivability, respectively. At a bile salt concentration of 0.5%, both isolates had a 75% survival rate. The isolates exhibited a high percentage of hydrophobicity and autoaggregation. The isolates also had non-hemolytic activity and were susceptible to many clinical tested antibiotics (tetracycline, erythromycin, ampicillin, gentamycin, penicillin, etc.). The isolate showed antimicrobial activity against enteric pathogens such as Staphylococcus aureus, Escherichia coli, and Shigella dysenteriae. The accession number of Bacillus subtilis MT279753 and MK453362 was submitted to NCBI. Conclusion: The result revealed that isolates have potent probiotic properties and possess a direct influence on the production of antimicrobial metabolites. These parameters can be modified for the improvement of the potentiality of the isolates

Lactic acid production from cassava fibrous residue using lactobacillus plantarum mtcc 1407

Abstract: During extraction of starch from cassava, fibrous residue is a major waste released into the environment. Owing to the high starch content (60-65% on dry weight basis) and organic matter of cassava fibrous residue (CFR), an attempt has been made to utilize it for the production of lactic acid (LA) in semi-solid state fermentation using Mann Rogassa Sharpe medium containing [5 % (wv -1 )] CFR in lieu of glucose [2 % (wv -1 )] as the carbon source. Response Surface Methodology (RSM) was used to evaluate the effect of main variables, i.e. incubation period, temperature and pH on LA production. The experimental results showed that the optimum incubation period, temperature and pH were 120 hr, 35 0 C and 6.5, respectively. Maximum starch conversion by Lactobacillus plantarum MTCC 1407 to LA was 63.3%. The organism produced 29.86 g of (L+) LA from 60 g of starch present in 100 g of CFR. The LA production yield (i.e. mass LA produced mass starch present in CFR -1 x 100) was 49.76 %