title: Identification of a new polyhydroxyalkanoate (PHA) producer Aquitalea sp. USM4 (JCM 19919) and characterization of its PHA synthase.
abstract: Aquitalea sp. USM4 (JCM 19919) was isolated from a freshwater sample at Lata Iskandar Waterfall in Perak, Malaysia. It is a rod-shaped, gram-negative bacterium with high sequence identity (99%) to Aquitalea magnusonii based on 16S rRNA gene analysis. Aquitalea sp. USM4 also possessed a PHA synthase gene (phaC), which had amino acid sequence identity of 77-78% to the PHA synthase of Chromobacterium violaceum ATCC12472 and Pseudogulbenkiania sp. NH8B. PHA biosynthesis results showed that wild-type Aquitalea sp. USM4 was able to accumulate up to 1.5 g/L of poly(3-hydroxybutyrate), [P(3HB)]. The heterologous expression of the PHA synthase gene of Aquitalea sp. USM4 (phaCAq) in Cupriavidus necator PHB-4 had resulted in PHA accumulation up to 3.2 g/L of P(3HB). It was further confirmed by1H nuclear magnetic resonance (NMR) analysis that Aquitalea sp. USM4 and C. necator PHB-4 transformant were able to produce PHA containing 3-hydroxyvalerate (3HV), 4-hydroxybutyrate (4HB) and 3-hydroxy-4-methylvalerate (3H4MV) monomers from suitable precursor substrates. Interestingly, relatively high PHA synthase activity of 863 U/g and 1402 U/g were determined in wild-type Aquitalea sp. USM4 and C. necator PHB-4 transformant respectively. This is the first report on the member of genus Aquitalea as a new PHA producer as well as in vitro and in vivo characterization of a novel PHA synthase from Aquitalea sp. USM4.
authors.affiliation: Ecobiomaterial Research Laboratory, School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia.
authors.forename: Lee-Mei
authors.initials: LM
authors.lastname: Ng
authors.affiliation: Ecobiomaterial Research Laboratory, School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia; Centre for Chemical Biology, Universiti Sains Malaysia, 10 Persiaran Bukit Jambul, Bayan Lepas, 11900 Penang, Malaysia. Electronic address: ksudesh@usm.my.
authors.forename: Kumar
authors.initials: K
authors.lastname: Sudesh
mesh_terms: D000217:Acyltransferases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D002861:Chromobacterium / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D003001:Cloning, Molecular; D020118:Cupriavidus necator / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D005618:Fresh Water / Q000382:microbiology; D010421:Pentanoic Acids / Q000378:metabolism; D010802:Phylogeny; D011091:Polyesters / Q000378:metabolism; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis*; D012336:RNA, Ribosomal, 16S / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D010421:Pentanoic Acids; D011091:Polyesters; D054813:Polyhydroxyalkanoates; D012336:RNA, Ribosomal, 16S; C042993:3-methylvaleric acid; D000217:Acyltransferases; C077225:poly(3-hydroxyalkanoic acid) synthase
keywords: Aquitalea; PHA producer; PHA synthase; PHA synthase activity; Polyhydroxyalkanoate; Substrate specificity