High-efficiency production of 5-aminovalerate in engineered Escherichia coli controlled by an anaerobically-induced nirB promoter.

Biobased production of 5-aminovalerate (5AVA) from biomass can support a sustainable and economic biorefinery process to produce bio-based nylon 5 for food packaging materials. Cost-competitive production of 5AVA from biomass is a key factor in the successful commercialization of nylon 5. Bioproduction of 5AVA is a promising candidate for the industrial process to the current petrochemical route. In this study, we developed an artificial 2-keto-6-aminocaproate-mediated pathway for cost-competitive and high efficiency production of 5AVA in engineered Escherichia coli. Firstly, the combination of native l-lysine α-oxidase (RaiP) from Scomber japonicas, α-ketoacid decarboxylase (KivD) from Lactococcus lactis and aldehyde dehydrogenase (PadA) from Escherichia coli could efficiently convert l-lysine into 5AVA. Moreover, the engineered strains ML03-P-RKP, ML03-P-RKP, ML03-P-RKP induced by anaerobic condition, temperature-induced, constitutive expression instead of expensive isopropyl β-D-thiogalactoside were constructed, respectively. The use of nirB promoter induced by anaerobic condition not only could attain a higher titer of 5AVA than PL-PR and M1-93 promoters, but omit cost of expensive exogenous inducers. After the replacement of industrial materials, 5AVA titer successfully reached 33.68 g/L in engineered strain ML03-P-RKP via biotransformation. This biotransformation process conduces to the cosmically industrial 5AVA bioproduction.