| Manufacturing
technology of PHA |
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Recommedation Tech |
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Manufacturing technology of PHA |
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Polyhydroxyalkanoate
(PHA) is one of storage polyesters synthesized
in some bacterial cells under unbalanced nutrient
conditions (e.g. short of nitrogen, or phosphorus,
or magnesium), functions as starch in plants
and fat in animals. It has been found to occur
in over 300 genera of bacteria, encompassing
Gram-positive and Gram-negative species. Over
90 kinds of PHA have been characterized, the
majority of them are composed of D-(-)-poly-3-hydroxyalknoic
acid monomers ranging from C3 to C14 (figure
1). With different R groups, chain lengths,
and site of hydroxyl group in monomers, various
PHAs are formed.
PHA can be classified
into three groups: short-chain-length PHA
with C3-C5 monomers, such as poly-3-hydrobutyrate(PHB);
medium-chain-length PHA with C6-C14 monomers,
such as poly-3-hydroxyoctanoate(PHO); and
copolymer by different monomers, such as poly-3-hydroxybutyrate-co-3-hydroxyvalerate(PHBV).
The water insoluble
PHA exhibits high molecular weight, thermoplastic
and/or elastomeric features as well as other
interesting physical and material properties.
Therefore, they have attracted increasing
attention from scientific and industrial communities
due to their interesting properties including
biodegradability, biocompatibility and piezoelectricity.
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