Abstract:
Polyhydroxyalkanoate (PHA) is scientifically acclaimed as a naturally biosynthesised,
biodegradable and biocompatible biopolymer that presents as an alternative to
petroleum-based plastic. Recognised as a bacterial hotspot, the marine sponge is an
acknowledged resource of novel natural products and genetic material, hence is a
desirable target for PHA-producing bacteria or PHA-polymerising genes. However,
due to the difficulty in cultivating sponge-associated bacteria plus the emergence of
bioinformatics and metagenomics tools, the medically and biotechnologically
appealing genes are increasingly exploited by bioengineering prior to biosynthesis.
Therefore, in this study, the bacterial diversity and PHA synthase genes (phaC) of
locally abundant yet underexplored sponges, explicitly Aaptos aaptos and
Xestospongia muta from Pulau Bidong along with A. aaptos from Pulau Redang, were
investigated. After metagenome extraction, bacterial diversity was analysed using
culture-independent 16S ribosomal ribonucleic acid (16S rRNA) amplicon sequencing.
Then, the phaC genes were screened, sequenced, identified and published in the
GenBank database. Three phaC labelled 2, 2B and 1B were closely similar to the phaC
of Pseudomonas sp., Rhodocista sp., and bacterium AR5-9d_16. Out of ninety-nine
dominant genera, twenty-six PHA-producing genera were detected among the three
bacterial communities. Geographical factors rather than host species notably
influenced sponge-associated bacterial communities.
