A New Facultative Alkaliphilic, Potassium Solubilizing, Bacillus Sp. SVUNM9 Isolated from Mica Cores of Nellore District, Andhra Pradesh, India

A new facultative alkaliphilic Bacillus species isolated from mica mines of Nellore district of Andhra Pradesh, India. This strain is gram positive, rod shaped, motile bacteria capable of growth in aerobic conditions up to pH 12.0 exhibiting optimum growth at pH 10.0. The strain is oxidative, catalase positive, urease positive, able to hydrolyse starch, gelatine, able to utilize lactose, Dglucose and sucrose and produce acids. It also converts nitrate into nitrite. Further, exhibited positive results for methyl red and Voges Proskauer reaction. The strain showed optimum growth at 0.5% NaCl and able to thrive even at higher concentration of sucrose. The 16S rDNA sequence showed 99% similarity with Bacillus sp19(HQ433576) and closest relative is Bacillus amyloliquifaciens (JN086147).The efficiency of this strain for potassium dissolution from insoluble mica was evaluated in vitro. Modified Alexandrov’s medium supplemented with 0.1% mica powder was used to investigate the potassium solubilising activity of the Bacillus spSVUNM9 strain. Final pH, total acidity, soluble K content and released organic acids were determined in culture media after 21days of incubation. The K content was increased to 2.5times greater than the control. Mineral potassium solubilisation was directly related to the pH drop by the strain. The analysis of the culture medium by high pressure liquid chromatography identified gluconic acid as the main organic acid released by Bacillus sp.SVUNM9.This study is the first report on the isolation and characterization of native potassium solubilising bacteria from mica ore.