Journal of Environmental Biology

Phosphate solubilizing actinomycetes in the estuarine environment: An inventory

Maloy Kumar Sahu¹, K. Sivakumar*¹, T. Thangaradjou¹ and L. Kannan²

*aurosiva@yahoo.co.uk

¹Centre of Advanced Study in Marine Biology, Annamalai University, Parangipettai-608 502, India

²Thiruvalluvar University, Vellore - 632 004, India

(Received: October 12, 2005 ; Revised received: May 10, 2006 ; Accepted: June 17, 2006)

Abstract: Sediment samples were collected from different stations of the Vellar estuary for isolation of total actinomycetes and phosphate solubilizing actinomycetes. Phosphatase activity in the sediments was also investigated. Consistently, a higher number of actinomycetes, phosphate solubilizing actinomycetes and phosphatase activity were recorded from the clay sediments than the sandy sediments at all the stations. In all, 7 strains showed positive phosphatase activity. Among them, one strain PS-3 exhibited good activity and was further investigated for optimum phosphorus solubilization at different pH (6, 6.5, 7, 7.5 and 8) and incubation (1^st day to 20^th day) periods. The solubilizing activity was maximum at the pH 7 and an incubation period of 13 days was required for an appreciable quantity of phosphorus to be leached into the medium. Based on the chemotaxonomical and conventional methods of identification, the strain PS-3 has been tentatively identified as Streptomyces galbus. The present study indicates that phosphatase enzyme and S. galbus along with other actinomycetes species would play a major role in solubilizing the phosphate in the estuarine ecosystem and increasing the soluble phosphate concentration thereby enhancing the productivity.

Key words:    Vellar estuary, Sediments, Actinomycetes, Phosphatase

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