Siderophores are small molecules that can easily bind to ferric iron. As a chelating agent, they transportiron molecules inside the bacterial cell for various biochemical reactions. Due to its various applicationsin medicinal, industrial and environmental related aspects, this paper deals with characterizationand optimization of few siderophores producing bacteria from the soil samples, collected from Chikkamagalurudistrict, Karnataka. The siderophores production was assayed qualitatively and quantitativelythrough Chrome Azurol S and the results showed positive for the strains VIT VK5 and VIT VK6 that grownin succinate medium. Further characterization and optimization results revealed that both the bacteriumhas the ability to yield siderophores ( ∼60–80% units) in the optimum condition of pH 8, at 37 °C withglucose and sucrose as a carbon source and NaNO3 as a nitrogen source. Thus, the study concludes thatstrains VITVK5 and VITVK6 can be promising candidates for the siderophores production which can playmajor applications in medicinal and industrial aspects.

The nano-sized particles make an imprint on us in our daily lives and it has great importance in the nu- merous fields of biotechnology like the food industry, medical and industrial field. Gold nanoparticles are one of the widely used particles as it has many therapeutic applications, such as drug delivery system for many diseases like cancer, cardiovascular diseases, diabetes mellitus etc. biosensors, and environmental applications of dye degradation, bioremediation of toxic chemicals present in the environment (soil and atmosphere). Gold nanoparticles synthesis by the green route has become the latest development, be- cause of the bioavailability of sources like plants or microorganisms, and it also reduces the utilization of toxic chemicals. This review explains the various microorganisms like bacteria, algae, fungi, actinomycetes and yeast involved in the synthesis of these nanoparticles also elucidate the size, shape and functional groups involved in the synthesis of nanoparticles and its applications.