Immobilization of Nickel by Bacterial Isolates from the Indian Ridge System and the Chemical Nature of the Accumulated Metal

Abstract

Bacterial isolates from Carlsberg-Ridge waters were tested for their ability to immobilize Ni. For this, test cultures were suspended for 60 d in seawater with and without added Ni at concentrations of 10 to 10,000 μ M. At an initial concentration of 100 μ M, isolates CR35 and CR48 caused a 89.8 and 6.95 μ M decrease in dissolved Ni at 28 2°C and a 14.75 and 6.38 μ M at 3 1°C. Analyses showed the contribution of hydroxyl, carbonyl, sulfide and phosphoryl groups in Ni binding. The study proves that Ni immobilization can occur even in the absence of Mn and suggests their plausible role in the ridge ecosystem.

Keywords:

• Carlsberg Ridge
• energy dispersive x-ray
• immobilization
• infrared spectroscopy
• nickel
• scanning electron microscope
• X-ray powder diffraction

We thank the Director, NIO for providing the required facilities to conduct this research work. The work has been carried out under the project “Preliminary exploration of cobalt-rich seamount crusts in the northern Indian Ocean” funded by the Ministry of Earth Sciences (Government of India) lead by Dr. V.K. Banakar. Dr. V.P. Rao helped with XRD and Dr. Keisham Sarjit Singh and Divya Shridhar with IR analysis. Dr. M.P. Tapaswi gave us unstinting support with required literature. Dr. Maria Judith B.D. Gonsalves critically went through the manuscript. SPP acknowledges the Council of Scientific and Industrial Research, New Delhi-India, for the award of Senior Research Fellowship. We thank the two anonymous reviewers who critically reviewed the manuscript and helped us to improve the contents. This manuscript has NIO contribution No. 4644.