Biochemical and physiological characterizations of Bacillus subtilis

Abstract

An investigation entitled “Biochemical and physiological characterizations of Bacillus subtilis” was undertaken at Plant Pathology Section, College of Agriculture, Nagpur during the year s2017-18. Fifteen isolates of Bacillus subtilis were isolated from rhizospheric soil of different crops. Out of 15 samples only 7 samples yielded Bacillus subtilis on the King’s B medium. The isolates were characterized by standard biochemical and physiological characters viz. Gram reaction, cell shape, colony, H2S production, gelatin liquefaction, starch hydrolysis, catalase test, KOH test, acid and gas production, phosphate solubilization and IAA production test were carried out. The bacteria found to be Gram positive and rod shaped. All the isolates shows maximum growth at 30 and 35oC temperature and grew well in 6 to 8 pH range. All the isolates were found positive for catalase test (except BS-4), positive for gelatine liquefaction, negative for KOH test, positive for acid and gas production, positive for H2S test (except BS-1 and BS-6), positive for starch hydrolysis (except BS-2, BS-5, BS-7), negative for IAA production, positive for phosphate solubilization (except BS-4). In this investigation antagonistic study of Bacillus subtilis against Xanthomonas axonopodis pv. citri. Also done and BS-5 recorded maximum inhibition zone which is 16.60 mm followed by BS-2 which is 16.20 mm. Minimum inhibition zone was recorded by BS-6 which is 15.20 mm.