Strategy for 4-Hydroxyvalerate Production Enhancement in Pseudomonas putida KT2440

Abstract

Levulinic acid (LA) is one of starting material for valuable C5 chemical. Because LA has a commercially high potential because it has a relatively low price and a growing market. Thus, many bacteria including LA catabolic pathway is very attractive as industrial host strain. Pseudomonas putida KT2440 is also one of them. P. putida KT2440 has high resistance to toxicity of organic solvent and oxygen stress, less side pathway and relatively low maintenance energy for growth. Above all, LA catabolic operon was already identified, and it includes 4-hydroxyvaleric-Coa, which can be converted to 4-hydroxyvalerate, which is a precursor of Gamma-valerolactone. Because Gamma-valerolactone is platform chemical that is convert to other valuable product such as green solvent or bio-fuel, we determined 4HV as the target product and regulated metabolic pathway of P. putida for accumulation of 4HV. We also tried to maximize the production of 4HV by detection and strengthening the side pathway involved in 4HV production by adaptive laboratory evolution and developing novel genetic engineering system for P. putida. As a result, we could construct fast growing P. putida strain in minimal media include LA, and increased 4HV production in P. putida.