Detection of siderophore production from hydrogen-oxidizing bacteria with CAS overlay plate method

Abstract:

[Objective] CAS(Chrome azurol S) overlay plate method was used for the detection of siderophore from hydrogen-oxidizing bacteria, to address the problem of growth inhibition for fungi and certain bacteria caused by hexadecyltrimethyl-ammonium bromide (HDTMA) in the popular CAS assay. [Methods] We just need to coverage the modified CAS medium on iron-free culture agar plates covered with colonies, then the problem of growth inhibition could be removed, due to the microorganisms tested with no direct contact with the hexadecyltrimethyl-ammonium bromide (HDTMA). [Results] Three strains of hydrogen-oxidizing bacteria, SDW-5, SDW-9, AaP-13 could form single colony, the siderophore halo around the colonies will form in an hour after a modified CAS medium is covered on iron-free culture agar plates. [Conclusion] This method successfully avoided growth inhibition problems, hence it could become a universal method for the detection of microorganisms siderophores.