Culture dependent and independent analysis and appraisal of early stage biofilm-fbrming bacterial community composition in the Southern coastal seawater of India

摘要

Microbial aggregation on artificial surfaces is a fundamental phenomenon in aquatic systems that lead to biofouling, corrosion and influence the buoyancy of plastic materials. Despite the maritime activities and with nearshore large industrial sector, Laccadive Sea in the Indian Ocean has rarely been investigated for characterizing early biofilm-forming bacterial community. The present investigation was aimed to catalogue the primary colonizers on artificial surfaces and their comparison with planktonic community in southern coastal seawater of India. Surface seawater samples and biofilm assembled on three artificial surfaces over a period of 72 h of immersion in the intake area of a nuclear power plant at Kudankulam, India were collected. The structure of surface assemblages and plankton were unveiled by employing culture dependent, DGGE and NGS methods. In static condition, a collection of aerobic heterotrophic bacteria was screened in vitro for their ability to form potent biofilm. Proteobacteria preponderated the communities both in seawater and natural biofilm and Gainmaproteobacteria accounted for 85% in the latter. Vibrionacene, Alteromonadaceae and Pseudoatteromonadaceae dominated the biofilm community and constituted for 41, 25 and 8%, respectively. In contrast to other studies that showed Rhodobacteracene family of Alphaproteobacteria as predominant component, we found Vibrionacene of Garnmaproteobacteria as dominant group in early stage of biofilm formation. Both DGGE and NGS data indicated that the attached community is noticeably distinct from those suspended in water column and form the basis for the proposed hypothesis of species sorting theory, that is, the local environmental conditions influence bacterial community assembly. Collectively, the data are testament for species sorting process that occur during initial assembly of bacterial community in marine environment and shed light on the structure of marine bacterial biofilm development. The outcome of the present study is of immense importance for designing long-term, efficient and appropriate strategies to control the biofouling phenomenon. (C) 2019 Elsevier B.V. All rights reserved.