Published July 6, 2017 | Version v1
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Photosynthetic poly-β-hydroxybutyrate accumulation in unicellular cyanobacterium Synechocystis sp. PCC 6714

  • 1. Technical University Vienna
  • 2. University of Applied Sciences Technikum Vienna


Poly-β-hydroxybutyrate (PHB) production from CO2 has the potential to reduce the production cost of this biodegradable polyesters,  and also to make the material more sustainable compared to utilization of sugar feedstocks. In this study the unicellular  cyanobacterium, Synechocystis sp. PCC 6714 has been identified as an unexplored potential organism for production of PHB.  Synechocystis sp. PCC 6714 was studied under various cultivation conditions and nutritional limitations. Combined effects of  nitrogen and phosphorus deficiency led to highest PHB accumulation under photoautotrophic conditions. Multivariate experimental  design and quantitative bioprocess development methodologies were used to identify the key cultivation parameters for PHB  accumulation. Biomass growth and PHB accumulation were studied under controlled defined conditions in a lab-scale  photobioreactor. Specific growth rates were fourfold higher in photobioreactor experiments when cultivation conditions were  controlled. After 14 days of cultivation in nitrogen and phosphorus, limited media intracellular PHB levels reached up to 16.4% from  CO2. The highest volumetric production rate of PHB was 59 ± 6 mg L−1 day−1. Scanning electron microscopy of isolated PHB granules of Synechocystis sp. PCC 6714 cultivated under nitrogen and phosphorus limitations showed an average diameter of  0.7 μm. The results of this study might contribute towards a better understanding of photoautotrophic PHB production from  cyanobacteria.



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