Jantima Teeka, Tsuyoshi Imai, Alissara Reungsang, Xuehang Cheng, Emma Yuliani, Jiruthakorn Thiantanankul, Nathaporn Poomipuk, Junki Yamaguchi, Anan Jeenanong, Takaya Higuchi, Koichi Yamamoto, Masahiko Sekine
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 179C°. 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. © Society for Industrial Microbiology and Biotechnology 2012.
Division of Environmental Science and Engineering, Yamaguchi University, Yamaguchi 755-8611, Japan; Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002, Thailand; Fermentation Research Center for Value Added Agricultural Products, Khon Kaen University, Khon Kaen 40002, Thailand; Water Resources Department, Faculty of Technology, Brawijaya University, Malang 65145, Indonesia; Medical Biotechnology Center, Department of Medical Sciences, Ministry of Public Health, Nonthaburi 11000, Thailand; UBE Technical Center (Asia) Limited, Muang Rayong district, Rayong 21000, Thailand; Division of Civil and Environmental Engineering, Yamaguchi University, Yamaguchi 755-8611, Japan
