Research

Culture independent molecular analysis of bacterial communities in the mangrove sediment of Sundarban, India

Abhrajyoti Ghosh^1,3* , Nirmalya Dey^1,4* , Amit Bera¹ , Amit Tiwari^1,5 , KB Sathyaniranjan¹ , Kalyan Chakrabarti² and Dhrubajyoti Chattopadhyay¹

¹  Department of Biochemistry and Department of Biotechnology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata- 700019, West Bengal, India

²  Department of Agricultural Chemistry & Soil Science, Institute of Agricultural Science, University of Calcutta, 35, Ballygunge Circular Road. Kolkata- 700019, West Bengal, India

³  Current address: Max Planck Research Group "Molecular Biology of Archaea", Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Strasse, D-35043 Marburg, Germany

⁴  Current address: Division of Nephrology Department of Medicine, 7703 Floyd Curl Drive, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229 3900, USA

⁵  Current address: Institute of Molecular Cancer Research, University of Zurich, 17 K 28, Winterthurerstrasse 190, Zurich-8057, Switzerland

author email corresponding author email* Contributed equally

Saline Systems 2010, 6:1doi:10.1186/1746-1448-6-1

Published:	17 February 2010

Abstract

Background

Sundarban is the world's largest coastal sediment comprising of mangrove forest which covers about one million hectares in the south-eastern parts of India and southern parts of Bangladesh. The microbial diversity in this sediment is largely unknown till date. In the present study an attempt has been made to understand the microbial diversity in this sediment using a cultivation-independent molecular approach.

Results

Two 16 S rRNA gene libraries were constructed and partial sequencing of the selected clones was carried out to identify bacterial strains present in the sediment. Phylogenetic analysis of partially sequenced 16 S rRNA gene sequences revealed the diversity of bacterial strains in the Sundarban sediment. At least 8 different bacterial phyla were detected. The major divisions of detected bacterial phyla were Proteobacteria (alpha, beta, gamma, and delta), Flexibacteria (CFB group), Actinobacteria, Acidobacteria, Chloroflexi, Firmicutes, Planctomycetes and Gammatimonadates.

Conclusion

The gammaproteobacteria were found to be the most abundant bacterial group in Sundarban sediment. Many clones showed similarity with previously reported bacterial lineages recovered from various marine sediments. The present study indicates a probable hydrocarbon and oil contamination in this sediment. In the present study, a number of clones were identified that have shown similarity with bacterial clones or isolates responsible for the maintenance of the S-cycle in the saline environment.