Bacillus tropicus and Bacillus safensis: A Potential Siderophore Producing Rhizospheric Bacteria: Its Characterisation and Optimisation.

Siderophore-Producing Rhizobacteria (SPR) have emerged as a viable approach to plant protection and crop health management in agriculture. It brings iron molecules into bacterial cells for use in a variety of metabolic processes, with applications in agriculture, medicine, industry, and the environment. In this study, 22 bacteria were isolated and screened for siderophore production from maize field soil. Seven of the 22 bacterial isolates showed discrete zones of orange colour, indicating siderophore production. However, only two potent siderophore-producing strains, Bacillus safensis (BMS-01) and Bacillus tropicus (BMS-15), were optimised and identified using physiological characteristics and 16S rDNA sequencing. After optimising siderophore production with glucose and sucrose as carbon sources and NaNO3 and (NH4)2NO3 as nitrogen sources, Bacillus safensis (BMS-01) and Bacillus tropicus (BMS-15) were found to have a significant ability to yield siderophore (60%-70% units) under ideal conditions of pH 8, 28°C. The study concludes that the strains Bacillus safensis and Bacillus tropicus show potential for siderophore production, which may warrant further investigation as biocontrol agents and plant growth promoters in future field trials.