Characterization of probiotic potential of Bacillus species isolated from a traditional brine pickle

Fermented foods are known for their potential as main source of probiotics. The present study aimed at investigating the probiotic properties of bacteria isolated from fermented mango pickle. Non-hemolytic fermenting microbiota isolated from mango pickle was screened in vitro for their basic probiotic properties such as acid tolerance, bile salt, lysozyme and salt tolerance. They were also tested for their beneficial characters like cholesterol removal, bacterial adhesion to hydrocarbons, auto-aggregation, antimicrobial activity, β-galactosidase activity, exopolysaccharide production and adhesion to HT-29 cell line. Outputs of these parameters were subjected to principal component analysis (PCA) and these results were interpreted to select prospective bacterial isolates that can be used as potential probiotics. Out of eight isolates, PUFSTP35 (Bacillus licheniformis), PUFSTP38 (Bacillus amyloliquefaciens) and PUFSTP39 (Bacillus subtilis) showed similar trend to Weissella cibaria (MTCC 9814) that was used as a reference strain for profiling probiotic properties. B. licheniformis PUFSTP35 from fermented mango pickle appear to be the most potential candidate for use as a beneficial probiotic.

An investigation on the diversity of mosquitocidal bacteria and its relationship with incidence of vector borne diseases

Control of mosquitoes is the most important aspect of public health, as mosquitoes transmit many human diseases, including the fatal infection, Japanese encephalitis. This paper addresses the isolation of new mosquitocidal bacteria from soil samples in the Union Territory of Pondicherry, India, where, no clinical cases of vector borne infections have been reported. Bacterial isolates from soil samples were screened for potential mosquitocidal strains and bioassays against mosquito vectors (Culex quinquefasciatus, Anopheles stephensi and Aedes aegypti) were carried out. Genomic DNA of potential mosquitocidal isolates was amplified and species identification was carried out using BLASTn program (NCBI). Phylogenetic analysis of 16S rRNA sequences of mosquitocidal bacteria revealed seven potential isolates. SDS-PAGE results have shown that there was considerable difference in the protein profiles. Numerical analysis revealed 4 distinct groups at similarity level 25%. The relationship between VBDs and prevalence of soil mosquitocidal bacteria in the study sites has elicited considerable interest in the diversity of mosquitocidal bacteria and their application for mosquito borne diseases control.

Isolation of mosquitocidal bacteria (Bacillus thuringiensis, B.sphaericus and B. cereus) from excreta of arid birds

Mosquitocidal bacteria are environmentally friendly alternatives to chemical insecticides for controlling mosquitoes and therefore, there have been tremendous world-wide efforts to identify novel mosquitocidal bacteria from natural environment. In the present study, excreta from arid-birds were analyzed for identifying mosquitocidal bacteria. The selection of sample for bacterial screening is significant, because, arid-birds are the unique living species and gathering the foods from variety of sources from environment. Out of 1000 samples examined, twelve bacterial strains were identified as mosquitocidal and the 16S rRNA gene sequence alignment depicted that these isolates belonged to Bacillus species (Bacillus thuringiensis, B.sphaericus and B. cereus). Toxicity assay against mosquito vectors have shown that these isolates are potential. The B. sphaericus VCRC-B547 (NCBI: JN377789) has shown a higher toxicity against Cx. quinquefasciatus, An. stephensi, and Aed. aegypti. Result from SDS-PAGE has shown that there was considerable difference in the protein profiles among the new bacterial isolates. Phylogenetic tree with branch length 0.05 revealed three distinct groups with homology among the closely related Bacillus strains. This study therefore throws considerable interest on the diversity of microbial organisms from arid birds and its application in mosquito control.

Purification and characterization of keratinase from feather degrading bacterium useful for mosquito control--a new report

Every day, food processing industries release wastes, which are environmental menance. Chicken feathers have been discarded in bulk as waste from poultry industries, globally. Degrading these wastes, as unused disposals, without acquiring any additional benefits has led to an idea to develop a new technology. We have reported earlier that Bacillus thuringiensis serovar israelensis (Bti) can be used for biodegradation of feather waste for biopesticide production. In the present study, purification and characterization of keratinase from feather degrading bacterium (Bti) is reported. Protein precipitate obtained at Ammonium sulphate saturation at 60% level and Sephacryl S-200 column chromatography resulted in 2.3 and 11.68 fold purification of the enzyme respectively. The purity was revealed in SDS-PAGE by a single band of molecular weight of 40 kDa and it was characterized. The optimum pH of the enzyme shifted to a more neutral range (6.0-8.0) with the highest activity (7.0). The optimum temperature of the reaction was determined to be 30ºC. The keratinase enzyme retained 51% residual activity (303 U/mg protein) at 70ºC (60 min) and the half-lives of the enzyme were 130 minutes at 40ºC, 90 min at 50ºC and of 60 min at 70ºC, respectively. Keratinase activity was enhanced by calcium and magnesium ions while EDTA, PMSF, β- mercaptoethanol and manganese inhibited the activity. This is the first report investigating the keratinase from Bti degraded chicken feathers for the bio-synthesis of mosquitocidal toxins.