Mining of aminotransferase genes for efficient bio-production of 1, 3-diaminopropane

With the increasing attention to environmental issues and sustainable development, bio-production of diamines from renewable raw materials is very important for the establishment of a sustainable nylon industry. A three carbon linear chain diamine, 1,3-diaminopropane (1,3-DAP), is an important platform chemical and has the potential for novel types of polyamides preparation. In this study, the C4 biosynthetic pathway for 1,3-DAP reported before was introduced into Escherichia coli W3110 and homolog mining of 2-ketoglutarate 4-aminotransferase genes was conducted to increase 1,3-DAP production. We demonstrated that aminotransferase RocD from Bacillus subtilis 168 was the most effective one among the candidates. Meanwhile, l-aspartate transporters such as GltP from E. coli, GltP and GltT from B. subtilis 168 were examined to further improve the 1,3-DAP production. Subsequently, the dual-vector systems were introduced to the host to co-express aminotransferases from different sources and the engineered E. coli W3110 could accumulate 302mg/L of 1,3-DAP with a yield of 0.31mol/mol (1,3-DAP/ l-aspartate) on the shake flask cultivation. The strategies reported here will be useful for the efficient and sustainable bio-based production of 1,3-DAP.