Owing to their photosynthetic capabilities, there is increasing interest in utilizing cyanobacteria to convert solar energy into biomass. 2-Deoxy-scyllo-inosose (DOI) is a valuable starting material for the benzene-free synthesis of catechol and other benzenoids. DOI synthase (DOIS) is responsible for the formation of DOI from d-glucose-6-phosphate (G6P) in the biosynthesis of 2-deoxystreptamine-containing aminoglycoside antibiotics such as neomycin and butirosin. DOI fermentation using a recombinant Escherichia coli strain has been reported, although a carbon source is necessary for high-yield DOI production. We constructed DOI-producing cyanobacteria toward carbon-free and sustainable DOI production. A DOIS gene derived from the butirosin producer strain Bacillus circulans (btrC) was introduced and expressed in the cyanobacterium Synechococcus elongatus PCC 7942. We ultimately succeeded in producing 400 mg/L of DOI in S. elongatus without using a carbon source. DOI production by cyanobacteria represents a novel and efficient approach for producing benzenoids from G6P synthesized by photosynthesis.
Keywords: 2-deoxy-scyllo-inosose; 2-deoxy-scyllo-inosose synthase; Cyanobacteria; DOI: 2-deoxy-scyllo-inosose; DOIS: 2-deoxy-scyllo-inosose synthase; G6P: d-glucose-6-phosphate; HPLC: high-performance liquid chromatography; IPTG: isopropyl β-d-1-thiogalactopyranoside; OD: optical density; PAGE: polyacrylamide gel electrophoresis; SDS: sodium lauryl sulfate; d-glucose-6-phosphate; photosynthesis.