Improvement of ectoine productivity by using sugar transporter-overexpressing Halomonas elongata

• Ectoine productivity from glucose was improved by using b3657 overexpressing H. elongata.
• Ectoine productivity from xylose was improved by using HEO_0208 overexpressing H. elongata.
• The transport of sugar is important for efficient ectoine production.
• We demonstrated that the HEO_0208 is the major xylose transporter in H. elongata.

We successfully enhanced the productivity of ectoine with Halomonas elongata by improvement of the transport of sugar. First, we carried out screening for sugar transporters capable of improving glucose and xylose consumption. We found two transporters: b3657 from Escherichia coli, which is capable of improving glucose consumption, and HEO_0208 from H. elongata, which is capable of improving xylose consumption. Using transporter-overexpressing strains, the productivity of ectoine was improved. These results indicate that sugar consumption is important for efficient ectoine production. As result of phenotypic analysis of a HEO_0208 deletion strain, we discovered that HEO_0208 is the major xylose transporter in H. elongata. This is the first report demonstrating improvement of ectoine productivity by enhancing the transport of sugar.