Cloning and characterization of poly(3-hydroxybutyrate) biosynthesis genes from Pseudomonas sp. USM 4-55
✍ Scribed by Yifen Tan; Pei-Chin Neo; Nazalan Najimudin; Kumar Sudesh; Tengku Sifzizul Tengku Muhammad; Ahmad Sofiman Othman; Razip Samian
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 411 KB
- Volume
- 50
- Category
- Article
- ISSN
- 0233-111X
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✦ Synopsis
Pseudomonas sp. USM 4-55 is a locally isolated bacterium that possesses the ability to produce polyhydroxyalkanoates (PHA) consisting of both poly(3-hydroxybutyrate) [P(3HB)] homopolymer and medium-chain length (mcl) monomers (6 to 14 carbon atoms) when sugars or fatty acids are utilized as the sole carbon source. In this study, the P(3HB) biosynthesis operon carrying the phbC Ps P(3HB) synthase was successfully cloned and sequenced using a homologous probe. Three open reading frames encoding NADPH-dependent acetoacetyl-coenzyme A reductase (PhbB Ps ), β-ketothiolase (PhbA Ps ) and P(3HB) synthase (PhbC Ps ) were found in the phb operon. The genetic organization of phb operon showed a putative promoter region, followed by phbB Ps -phbA Ps -phbC Ps . phbR Ps which encoded a putative transcriptional activator was located in the opposite orientation, upstream of phbBAC Ps . Heterologous expression of pGEM″ABex harboring phbC Ps in Escherichia coli JM109 resulted in P(3HB) accumulation of up to 40% of dry cell weight (DCW).