IGEM:IMPERIAL/2009/Encapsulation/Phase2/Alginate Biosynthesis/Bacteria2

=A.vinelandii=

Properties of bacteria
A.vinelandii is non-pathogenic soil bacterium

In its lifecycle, forms a spherical dormant cyst with alginate being important component. The cyst is protective against dessication and environment.

The complete sequence of A. vinelandii genome has recently been sequenced. Alginate5

Metabolic engineering is currently underway to increase alginate production. Alginate1

Biosynthesis




basically similar to P.aeruginosa

Main difference is the presence of a larger number of epimerase genes.

Epimerase genes
seven homologous secreted mannuronan C-5 extracellular epimerases AlgE1-7

secreted by bacteria into extracellular environment and acts on polymannuronate

each epimerase produces introduce G with varying patterns


 * AlgE2 introduces G-blocks (gel-forming alginate).
 * AlgE1 and E6 are also G-block forming enzymes.
 * AlgE4 produces alternating MG blocks

the properties of the AlgE epimerases have been extensively studied in vitro after recombinant expression in Escherichia coli Alginate2

the AlgE epimerase has been cloned into E.coli to produce epimerase. The epimerase was purified and mixed with alginate to improve the G-block quality of alginate. Alginate3

transport of epimerase
In silico identification of Type I secretion machineries eexD-F required to transport AlgE epimerase out of cell Alginate3



inactivation of the genes (eexD–F) encoding a particular Type 1 protein transport system leads to blocked AlgE transport Alginate2

Useful Papers

 * 1) Alginate1 pmid=17306024


 * 1) Alginate2 pmid=18373676


 * 1) Alginate3 pmid=8188585


 * 1) Alginate4 pmid=16855245


 * 1) Alginate5 pmid=19429624