Studies on siderophore producing halophilic and halotolerant bacteria adhered to mangrove plant litter

Abstract

Mangroves are unique ecosystems due to their ability to thrive in salt and saline water. In this ecosystem the nutrient recycling occurs consistently with the formation of detritus. Microbes play a major role in recycling and therefore factors affecting their growth influence the rate of mineralization. One of the factors is the availability of iron, the availability of which is limited. Under such conditions bacteria produce iron sequestering ligands called siderophores which help to get iron in soluble form that can be used by the bacterial cell for its cellular and metabolic needs. A total of 34 isolates were obtained by plating on Zobell marine agar and NaCl-tryptone-yeast extract agar. Amongst these 68 percent were found to be halophilic and 32 percent were halotolerant bacteria based on their ability to grow in varied salt concentrations. Further screening of the selected isolates for production of siderophores using CAS medium showed that 97 percent produced siderophores. The 4 best isolates were further identified based on biochemical and molecular characterization and two were identified to be Halobacillus sp, and the other two as Acinetobacter schindleri and Brevibacterium casei.