Abstract

CHARACTERIZATION AND IDENTIFICATION OF BIO-FILM FUNGAL CONSORTIA ISOLATED FROM DRINKING WATER PVC PIPELINES

N. Supraja*

ABSTRACT

Biofilm formation in drinking water PVC pipelines is due to many factors including pH, temperature, salt etc. In this study, microbiological aspects of biofilm formation and their role on electrochemical studies are presented. We report the design and evaluation of PCR primers ITS-1 and ITS-4 for amplification of rDNA genes from fungal isolates. Their specificity and efficacy were tested systematically with a variety of fungal species and environmental samples. They were found to be more useful for rDNA gene amplification in ecological and systematic studies than PCR amplimers that are currently more generally used. The primers showed good specificity for the fungal sp and the approximately 389-bp product was amplified exclusively. PCR sensitivity ranged from 100 fg to 10 ng for DNA extracted from all Fungal sp. Phylogenetic analysis of partially sequenced rDNA gene sequences revealed the diversity of fungal strains in the PVC pipeline scale samples; At least 5 different bacterial phyla were detected. PCR primers that target the bacterial rDNA gene were used to identify 8 putative fungal pathogens present in drinking water PVC pipelines. The occurrence of 5 fungal species namely Rhizopus oryzae strain, Aspergillus parvisclerotigenus strain, Meyerozyma caribbica strain, Tricoderma asperellum and uncultured fungus clone were identified. In addition, localized biofilm of the PVC pipeline in the presence of the consortia was observed by scanning electron microscopy analysis and morphology was seen in EPI fluorescence microscopy, Electrochemical studies were seen in impedance and polarization data. The dominant fungal species identified in the PVC pipeline biofilm samples were Aspergillus sp, respectively. Therefore, several types of fungi may be involved in biofilm arising and the potential role of each species in biofilm formation is discussed.

Keywords: PVC pipelines, Biofilm formation, Fungi, Phylogenetic tree construction, SEM analysis, Electro chemical studies.