title: Characterization of polyhydroxyalkanoates (PHAs) biosynthesis by isolated Novosphingobium sp. THA_AIK7 using crude glycerol.
abstract: Biodiesel-contaminated wastewater was used to screen for PHAs-producing bacteria by using crude glycerol as the sole carbon source. A gram-negative THA_AIK7 isolate was chosen as a potential PHAs producer. The 16S rRNA phylogeny indicated that THA_AIK7 isolate is a member of Novosphingobium genus which is supported by a bootstrap percentage of 100% with Novosphingobium capsulatum. The 1,487 bp of 16S rRNA gene sequence of THA_AIK7 isolate has been deposited in the GenBank database under the accession number HM031593. Polymer content of 45% cell dry weight was achieved in 72 h with maximum product yield coefficient of 0.29 g PHAs g⁻¹ glycerol. Transmission electron micrograph results exhibited the PHAs granules accumulated inside the bacterial cell. PHAs polymer production in mineral salt media supplemented with 2% (w/v) of crude glycerol at initial pH 7 was extracted by the sodium hypochlorite method. Polymer film spectrographs from Nuclear magnetic resonance displayed a pattern of signal virtually identical to spectra of commercial PHB. Thermal analysis by Differential scanning calorimeter showed a melting temperature at 179°C. Molecular weight analysis by Gel permeation chromatography showed two main peaks of 133,000 and 700 g mol⁻¹ with weight-average molecular weight value of 23,800 and number-average molecular weight value of 755. Endotoxinfree of PHAs polymer was preliminarily assessed by a negative result of the gel-clot formation, Pyrotell® Single test vial, at sensitivity of 0.25 EU ml⁻¹. To our knowledge, this is the first reported test of endotoxin-free PHAs naturally produced from gram-negative bacteria which could be used for biomedical application.
authors.affiliation: Division of Environmental Science and Engineering, Yamaguchi University, Yamaguchi 755-8611, Japan.
authors.forename: Jantima
authors.initials: J
authors.lastname: Teeka
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Imai
authors.forename: Alissara
authors.initials: A
authors.lastname: Reungsang
authors.forename: Xuehang
authors.initials: X
authors.lastname: Cheng
authors.forename: Emma
authors.initials: E
authors.lastname: Yuliani
authors.forename: Jiruthakorn
authors.initials: J
authors.lastname: Thiantanankul
authors.forename: Nathaporn
authors.initials: N
authors.lastname: Poomipuk
authors.forename: Junki
authors.initials: J
authors.lastname: Yamaguchi
authors.forename: Anan
authors.initials: A
authors.lastname: Jeenanong
authors.forename: Takaya
authors.initials: T
authors.lastname: Higuchi
authors.forename: Koichi
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Masahiko
authors.initials: M
authors.lastname: Sekine
mesh_terms: D056804:Biofuels; D002152:Calorimetry, Differential Scanning; D002850:Chromatography, Gel; D005990:Glycerol / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis*; D042301:Sphingomonadaceae / Q000145:classification / Q000235:genetics / Q000378:metabolism*
chemical_list: D056804:Biofuels; D054813:Polyhydroxyalkanoates; D005990:Glycerol