PHB Production with Wastes

PHAs can substitute petroleum-derived polymers, can be produced from renewable resources and are harmless to the environment due to their biodegradability. However, the major hurdle facing commercial production and application of PHA in consumer products is the high cost of bacterial fermentation. It makes bacterial PHA production 5 10 times more expensive than the petroleum-derived polymers such polyethylene and polypropylene. The significant factor of the production cost of PHA is the cost of substrate (mainly carbon source). In order to decrease this cost, the use of cheap carbon sources as substrates have been developed. The researches have been carried out to develop recombinant strains utilizing a cheap carbon source, while corresponding fermentation strategies have been developed and optimized. 

The percolate from the organic wet fraction (OWF) of household waste is considered the most suitable substrate for PHA production. It has a very high volatile fatty acid concentration, is available in large quantities and can be transported easily. The heavy metal content can be removed by precipitation. There are also several reports on the production of volatile fatty acids from anaerobically treated pahn oil mill effluent (POME) and utilization of these organic adds for the production of PHA.  

The uses of alternative carbon sources and corresponding strain developments have been reported. These include glycerol as co-product of many industrial processes using P. oleovoram wastewater using activated sludge, 

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