Application Of The Polyhydroxyalkanoate Synthase Of Chromobacterium Sp. Usm2 For The Production Of Biodegradable Plastics
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Date
2010-05
Authors
Bhubalan, Kesaven
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
A local isolate, Chromobacterium sp. USM2 was found to synthesize
polyhydroxyalkanoate (PHA) with very high molar fractions of 3-hydroxyvalerate
(3HV) monomer under certain culture conditions. The PHA synthase gene of this
isolate was cloned and expressed in a mutant Cupriavidus necator PHB−4. Interestingly,
the synthase was able to incorporate 3-hydroxyhexanoate (3HHx) monomer when this
transformant was cultured with palm oil as the sole carbon source. In this study, the
PHA synthase of Chromobacterium sp. USM2 (PhaCCs) was characterized via in vivo
and in vitro assays using Escherichia coli JM109 to better understand its ability to
synthesize PHA. Results from the in vitro assays showed that the expression level of
PhaCCs was higher compared to the PHA synthase of C. necator H16 (PhaCCn) which
was used as a positive control. This phenomenon was clearly exhibited in the SDSPAGE
and Western blot analyses. The total enzyme activity of PhaCCs (2132 U/g) was
nearly 8-fold higher compared to that of PhaCCn (253 U/g). These findings were further
supported by the results obtained from in vivo assay whereby the E. coli transformant
was able to produce 76 ± 2 wt% of poly(3-hydroxybutyrate) homopolymer within 24 h
of cultivation with glucose.
Description
Keywords
Polyhydroxyalkanoate Synthase , Chromobacterium Sp. Usm2