Production of PHA in Microorganisms and Plants

Selection of suitable carbon substrates is also another critical factor that determines the overall performance of the fermentation process as well as significantly influencing the cost of the final product. Therefore, the simplest approach 

Spirulina platensis Jau etal., 2004) Chlorogloea fritschii(Can etal., 1966) 

PHA is produced by different bacterial strains. One of the most studied strain is C. necator (formerly known as Wautersia eutropha, Ralstonia eutropha or Alcaligene eutrophus). It was used in industrial production by Imperial Chemical Industries (ICI PLC) to produce P(3HB-co-3HV) under the trade name of BiopoF. The Biopol patents have now been acquired by Metabolix Inc. (USA) (Verlinden et al. 2007). Until now, C. necator is still being used widely for bacterial fermentation as it is an efficient strain. Other important strains that have been studied for PHA production are Bacillus spp., Alcaligenes spp.. Pseudomonas spp., Aeromonas hydrophila, Rhodopseudomonas palustris, recombinant Escherichia coli, Burkholderia sacchari, and Halomonas boliviensis (Verlinden et al. 2007). 

necator is the model bacterium for the biosynthesis of PHA. This strain generally initiates the synthesis of PHA when either nitrogen or phosphorous is limited during growth (Kahar et al. 2004). A similar phenomenon occurs in several other PHA producers including Burkholderia cepacia (Zazali and Tan 2005 Mitomo et al. 1999), Pseudomonas sp. (Choi et al. 2003), and A. hydrophila 

The approach of producing P(3HB) from CO2 is probably the ideal way of maintaining the carbon balance in the ecosystem (System B in Fig. 2.7). The idea is commercially attractive because it is based on the concept of sustainability and the utilization of the cheapest renewable source as the starting material. Higher plants naturally could not accumulate P(3HB) due to the absence of key enzymes 

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