Chemistry Reference
In-Depth Information
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CHAPTER 3
Recovery and Extraction of
Polyhydroxyalkanoates (PHAs)
MITRA MOHAMMADI*
a
AND
MANSOUR GHAFFARI-MOGHADDAM
b
a
Department of Environmental Science, Kheradgerayan Motahar Institute
of Higher Education, Mashhad, Iran;
b
Department of Chemistry,
Faculty of Science, University of Zabol, Zabol, Iran
*Email: m.mohammdi@motahar.ac.ir; mitramohammadi@gmail.com
3.1 Introduction
The cost of PHA production is mainly affected by downstream processing
and therefore, the development of PHA extraction methods is required to
make the overall process much simpler and cheaper.
1
Improved bio-
separation systems are essential for biotechnology as separation is the
limiting parameter for the success of biological processes.
2
The recovery
system may affect the amount of product recovery, the convenience of the
subsequent purification steps and the quality of the final product. Cell
separation from fermentation broth is the preliminary step of the recovery
method.
3
Figure 3.1 shows the morphology of PHA granules in a bacteria cell
when observed using a transmission electron microscope (TEM). In order to
recover the PHA granules, it is necessary to rupture the bacterial cell and
remove the protein layer that coats the PHA granules. Alternatively, the PHA
has to be selectively dissolved in a suitable solvent. Generally, two methods
are usually utilized for the recovery and purification of PHA from a cell
biomass, which include PHA solubilization or non-PHA cell mass (NPCM)
dissolution. In the first one, PHA granules are dissolved in a suitable organic
.
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