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Thermophilic production of polyhydroxyalkanoates by a novel Aneurinibacillus strain isolated from Gudao oilfield, China
Author(s) -
Xiao Zijun,
Zhang Yu,
Xi Lijun,
Huo Fangfang,
Zhao Jingyi,
Li Jing
Publication year - 2015
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.201400843
Subject(s) - polyhydroxyalkanoates , thermophile , fermentation , firmicutes , thermus , strain (injury) , mesophile , food science , bacteria , chemistry , 16s ribosomal rna , biochemistry , biology , enzyme , genetics , anatomy , gene
Polyhydroxyalkanoates (PHAs) are usually biosynthesized using mesophilic strains, but the fermentation processes often suffer from bacterial contamination. This work reports the screening of thermophilic bacteria capable of producing PHAs under elevated temperatures to reduce the contamination risk. Strain XH2 was isolated from an oilfield and identified as Aneurinibacillus sp. by morphology, physiological‐biochemical characterization, and 16S rDNA phylogenetic analysis. This strain can produce PHA granules, which was detected by Nile red staining and transmission electron microscopic imaging. At 55 °C, 111.6 mg l −1 of PHA was produced in a fermentation medium containing glucose, peptone, and yeast extract. If peptone was removed from the medium, the yield of PHA would be enhanced by 2.4 times. The main monomers of the PHA product were identified to be 3‐hydroxybutyrate and 3‐hydroxyvalerate with a molar ratio of 17.2:1 by gas chromatography‐mass spectroscopy (GC‐MS) and nuclear magnetic resonance analyses. Two minor homologues, 3‐hydroxyoctanoate, and 3‐hydroxy‐4‐phenylbutanoate, were tentatively identified by GC‐MS as well. This is the first report of thermophilic PHA bacterial producer from the Firmicutes phylum.