10.22376/ijpbs.2019.10.1.p1-12 Volume 4 Issue 3 2013 (July - September) Natural population of lessThan i greaterThan Drosophila lessThan /i greaterThan lessThan i greaterThan ananassae lessThan /i greaterThan flies were captured from the locality of Burdwan (West Bengal, India) and were cultured under aseptic conditions. Midguts of the third instar larvae were dissected under a binocular microscope in laminar air flow for the isolation of the bacteria. The phenotyping, biochemical and 16S rRNA phylogeny identified the most prevalent bacteria as lessThan i greaterThan Paenibacillus nanensis lessThan /i greaterThan P012 (JQ782427) and lessThan i greaterThan Bacillus cereus lessThan /i greaterThan P013 (JQ782428) which was obtained all through the year. Both the bacteria were gram negative, spore forming, rod shaped, showed positive result for catalase, methyl red test, nitrate reduction, oxidase test, urease test but negative for indole production, Vogues-Proskauer test and starch hydrolysis. The antibiotic tetracycline (30µg), doxycycline hydrochloride (30µg), gatifloxacin (5µg), ofloxacin (5µg), levofloxacin(5µg) are sensitive and ampicillin(10µg), chloramphenicol (30µg) showed resistant by antibiotic sensitivity test. Phylogenetic affiliation of the bacteria (P012 and P013) was done by 16S rRNA gene sequence analysis and phylogenetic tree was constructed through multiple sequence alignments followed by a neighbor-joining analysis. PRIYANKA MAJI, CHANDRASEKHAR CHAKRABARTI AND SOUMENDRANATH CHATTERJEE Drosophila ananassae, gut-bacteria, Paenibacillus nanensis P012 (JQ782427), Bacillus cereus P013 (JQ782428), 16S rRNA gene sequence, Phylogenetic tree. 697-707