Biosynthesis and characterization of polyhydroxyalkanoates in the polysaccharide-degrading marine bacterium Saccharophagus degradans ATCC 43961

The marine bacterium Saccharophagus degradans was investigated for the synthesis of polyhydroxyalkanoates (PHAs), using glucose as the sole source of carbon in a two-step batch culture. In the first step the microorganism grew under nutrient balanced conditions; in the second step the cells were cultivated under limitation of nitrogen source. The biopolymer accumulated in S. degradans cells was detected by Nile red staining and FT-IR analysis. From GC-MS analysis, it was found that this strain produced a homopolymer of 3-hydroxybutyric acid. The cellular polymer concentration, its molecular mass, glass transition temperature, melting point and heat of fusion were 17.2 +/- 2.7% of dry cell weight, 54.2 +/- 0.6 kDa, 37.4 +/- 6.0 degrees C, 165.6 +/- 5.5 degrees C and 59.6 +/- 2.2 J g(-1), respectively. This work is the first report determining the capacity of S. degradans to synthesize PHAs.