Amplification and sequence analysis of phaC gene of polyhydroxybutyrate producing Vibrio azureus BTKB33 isolated from marine sediments

Abstract

Vibrios have shown their potential as polyhydroxyalkanoates (PHAs) producers, but until recently little information was available about their PHA-related genes. The present study attempts to characterize the phaC genes from a potent PHA-accumulating bacterium, Vibrio azureus strain BTKB33, isolated from marine sediments. The molecular detection of class I PHA synthase gene in the V. azureus strain BTKB33 gave the required amplicon and was confirmed by subsequent seminested PCR; however, a class II PHA synthase gene was not detected. The in silico characterization of the PCR product helped to deduce the presence of class I PHA synthase, particularly a polyhydroxybutyrate polymerase. Sequence alignment of the nucleotide sequence of class I PHA synthase of strain BTKB33 and other related Vibrio sp. showed intra-generic variation within genus Vibrio and this is revealed in the dendrogram. The multiple sequence alignment of the in silico-translated phaC gene of BTKB33 with the protein sequence of PHA synthase of related organisms showed the conserved regions of protein sequences within the genus Vibrio and the dendrogram constructed showed the relatedness based on the deduced amino acid sequences.