Part:BBa_K2963039

Producing γ-PGA with different D/L glutamate monomer ratio(R).

Usage and Biology

The BCA genes from Bacillus sp. encode a γ-PGA synthetase located on the cell membrane which is capable of polymerizing glutamic acid to form poly-γ-glutamic acid. In Bacillus licheniformis BCA are called capBCA. We mutated the B gene into B*. The racE gene is derived from Bacillus subtilis and it encodes a racemase which can converts L-glutamate to D-glutamate.

We used this part to produce different D/L monomer ratios of γ-PGA. We assembled the capB*CA genes and racE gene (BBa_K2963032) together to construct this part using plasmid PZM1.

Characterization

We transferred this part into our chassis microorganism Corynebacterium glutamicum using plasmid PZM1. And we using HPLC to detect the D/L monomer ratio of γ-PGA.The result shows as below.

Picture1 is the L-glutamate monomer ratio in γ-PGA we have produced using part BBa_K2963009 and the result reaches about over 90%.

Picture2 is the result of BBa_K2963039. This part contains capBCA genes and racE gene which is under the control of tac promoter with one lacO. The L-glutamate monomer ratio reaches about 32%.

This part is working. All the results show that we have achieved the goal of producing different D/L glutamate monomer ratio of γ-PGA preliminary.