Microbial synthesis of cis,cis-muconic acid by Sphingobacterium sp. GCG generated from effluent of a styrene monomer (SM) production plant

Sphingobacterium sp. GCG was isolated from the sewage of a styrene monomer manufacturing factory in Taiwan. This bacterium could utilize benzoic acid to synthesize cis,cis-muconic acid. Production of cis,cis-muconic acid by Sphingobacterium sp. strain is growth-associated. It was found that the strain through the BS-type (benzoic acid/succinic acid) culture medium with succinic acid as a growth carbon source exhibits better growth rate than the other mediums. It was also found that glutamate used as a nitrogen source could optimize the production of cis,cis-muconic acid. In addition, an increment of ca. 75–100% of cis,cis-muconic acid could be obtained by adding EDTA–FeCl3 complex solution, since the enzyme catA, a necessary oxygenase to convert catechol to cis,cis-muconic acid, consists of 2 Fe(III) ions as the cofactor. On the other hand, a five-fold increase in the yield of cis,cis-muconic acid was observed when proceeded under fed-batch culture.