Background:
Zymomonas mobilis
, as a novel platform for bio-ethanol production, has been attractedmore attention
and it is very important to construct vectors for the efficient expression of foreign genes in this bacterium.
Results:
Three shuttle vectors (pSUZM1, pSUZM2 and pSUZM3)were first constructedwith the origins of replication
from the chromosome and two native plasmids (pZZM401 and pZZM402) of
Z. mobilis ZM4, respectively. The three
shuttle vectorswere stable in
Z. mobilis ZM4 and have 3, 32 and 27 copies, respectively. The promoter P
pdc (a), from
the pyruvate decarboxylase gene,was cloned into the shuttle vectors, generating the expression vectors pSUZM1(2,
3)a. The codon-optimized glucoamylase gene from
Aspergillus awamori
combined with the signal peptide sequence
from the alkaline phosphatase gene of
Z. mobilis was cloned into pSUZM1(2, 3)a, resulting in the plasmids
pSUZM1a-GA, pSUZM2a-GA and pSUZM3a-GA, respectively. After transforming these plasmids into
Z. mobilis
ZM4, the host was endowed with glucoamylase activity for starch hydrolysis. Both pSUZM2a-GA and
pSUZM3a-GA were more efficient at producing glucoamylase than pSUZM1a-GA.
Conclusions:
These results indicated that these expression vectors are useful tools for gene expression in
Z. mobilis
and this could provide a solid foundation for further studies of heterologous gene expression in
Z. mobilis.
