Journal of Environmental Biology

Development of polyvinyl chloride biofilms for succession of

selected marine bacterial populations

Author Details

V. Balasubramanian

Department of Marine Science, Bharathidasan University, Tiruchirappalli - 620 024, India

S. Palanichamy

Offshore Platform and Marine Electrochemistry Centre, Central Electro Chemical Research Institute,

Tuticorin Unit, Tuticorin - 628 004, India

G. Subramanian

Offshore Platform and Marine Electrochemistry Centre, Central Electro Chemical Research Institute,

Tuticorin Unit, Tuticorin - 628 004, India

R. Rajaram

(Corresponding author)

Department of Marine Science, Bharathidasan University, Tiruchirappalli - 620 024, India

e-mail: drrajaram69@rediffmail.com

Publication Data

Paper received:

26 June 2010

Revised received:

15 November 2010

Re-revised received:

29 December 2010

Accepted:

08 January 2011

Abstract

Present investigation was made to bring out the pattern of biofilm formation by heterotrophic bacteria on non-toxic material, polyvinyl chloride (PVC) sheet fitted wooden rack that was immersed in seawater and the study was conducted in Tuticorin coast. Samplings were made over a period of 7 days with the following time period intervals: 30 min, 1, 2, 4, 24, 48, 72, 96, 120 and 144 hr. Bacterial enumeration was made by spread plate method on nutrient agar medium and characterization of bacterial isolates up to generic level was done. Gram-negative bacteria like Pseudomonas sp., Enterobacter sp., Aeromonas sp., Cytophaga sp. and Flavobacterium sp. were found to be the pioneer in colonizing the surface within 30 min and seven genera were represented in the biofilm. Among them two genera were found belonging to Gram-positive groups which included Micrococcus and Bacillus sp. The early stage biofilm i.e. up to 24^th hr was wholly constituted by Gram-negative groups. However, the population density of Pseudomonas sp. was found to be higher (315 CFU) when compared to other Gram-negative forms. Occurrence of Gram-positive group was noted only at 48^th hr old biofilm (28 to 150 CFU). The period between 48 and 96^th hr was the transition where both the Gram-negative and Gram-positive groups co- existed. After 96^th hr, the biofilm was found constituted only by Gram- positive groups. The isolates of early stage biofilm were found to produce allelopathic substance like bacteriocin.

Key words

Marine biofilm, Bacterial succession, Biofouling

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