Part:BBa_K2533049

RBS-lldP-RBS-ldhA

L-lactate permease & D-lactate dehydrogenase

Usage and biology

It encodes L-lactate permease and D-lactate dehydrogenase, which could produce and transport lactate. mleS could convert malic acid to L-lactate. lldP could transport lactate out of the cell. In this way, Rhodopseudomonas palustris could efficiently transport produced lactate out of the cell, which later will be used by Shewanella.

Characterization

This is one section for lactate utilization part.

Figure1:RBS-lldP-RBS-ldhA

DNA Gel Electrophoretic

To make sure that we get the target gene, we did the DNA gel electrophoretic to separate different gene. And here is the result.

Figure2:Verification of successful transformation of pSB1C3-RBS-lldP-RBS-ldhA

Our target genes are 2690bp, and as the marker is DS5000, we could be sure that the bright bands in this picture are our target genes.

Electrogenesis

By comparing the ability of producing electricity, we might find out whether dld could effectively help Shewanella to produce more electricity.

Figure3:shows that our modification is effective. Every gene circuits can help strains produce lactate, and mleS-lldP-ldhA is the most efficient one. Therefore, our construction of gene circuits achieves the goal to help strains produce lactate.

It could be demonstrated that targeted genes could be expressed in the engineered cells. More NADH has been produced by engineered bacteria, which helps to produce more electricty.