Patent ID: 8158389

Claim:
A method of producing R,R monatin by converting tryptophan to indole-3-pyruvate using a first aminotransferase, converting indole-3-pyruvate to R-2-hydroxy 2-(indole-3-ylmethyl)-4-keto glutaric acid (“R-monatin precursor”) using an R-specific aldolase, and converting R-monatin precursor to R,R monatin using either the first aminotransferase or a second aminotransferase, the method comprising: a) genetically engineering a bacteria to express: i) a nucleic acid that encodes the first aminotransferase; ii) where a second aminotransferase is present, a nucleic acid that encodes the second aminotransferase; iii), a nucleic acid that encodes the R-specific aldolase; and iv) a nucleic acid that encodes one or more polypeptide components of a multi-drug transporter system, wherein said polypeptide components are selected from the group consisting of AcrA, AcrB, EmrA, and EmrB, and wherein said multi-drug transporter system is capable of secreting R,R monatin; b) culturing the microorganism, wherein the microorganism expresses nucleic acids sufficient for the intracellular synthesis of R,R monatin; c) secreting R,R monatin using the one or more polypeptide components of the multi-drug transporter system; and d) collecting at least a portion of the secreted R,R monatin.