Production enhancement and characterization of the polyhydroxyalkanoate produced by Natrinema ajinwuensis (as synonym) ≡ Natrinema altunense strain RM-G10

Application of halophiles can decrease the cost of polyhydroxyalkanoate (PHA) production or bioplastic which are an alternative to the petroleum-derived plastic. Extremely halophilic archaeon, Natrinema ajinwuensis RM-G10 accumulated 61.02 +/- 0.68% PHA of its cell dry mass at 72 h in repeated batch cultures yielding 0.210 +/- 0.001 g L-1 h(-1) volumetric productivity after selection of the best cultivation conditions. Transmission electron microscopy showed the presence of PHA granules inside the archaeal cells. Characterization by gas chromatographic analysis, gas chromatographic-mass spectrophotometric analysis, thermogravimetric analysis, differential scanning calorimetric analysis, X-ray diffraction analysis, Fourier transform infra red spectroscopy and nuclear magnetic resonance spectroscopy revealed the polymer to be poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with 13.93 mol% 3-hydroxyvalerate content and having 35.45% crystallinity, -12.3 degrees C glass transition temperature, 143 degrees C and 157.5 degrees C melting temperatures and 284 degrees C degradation temperature. This is the first report on production enhancement (on a small scale) and characterization of the polyhydroxyalkanoate produced by Natrinema ajinwuensis (as synonym) Natrinema altunense strain RM-G10 and the Natrinema genus in general. (C) 2017 Elsevier B.V. All rights reserved.