Polyamine biosynthesis-driven CO2 capture for sustainable applications

Carbon dioxide (CO₂) is a major greenhouse gas, with significant emissions from fossil fuel combustion and biological activities. CO₂ emissions from biological processes are particularly dispersed and variable, making capture and carbon utilization challenging. In this study, by coupling the engineered biosynthesis of polyamine with self-driven in situ CO₂ capture, we successfully achieved efficient CO₂ fixation. In particular, an acid-resistant cadaverine-producing lysine decarboxylase (CadA) was transformed using surface engineering to yield the effective alkali-resistant mutant CadA-M2, which exhibited the lowest K m and highest k cat /K m in the range of pH 7.0 to 10.0. Then 297.0 g/L of cadaverine was achieved in a 5 L single-batch bioreactor, the highest reported titer to date, while 85% of released CO₂ was converted to bicarbonate and utilized to synthesize C 3 compound malonic acid, yielding diamines and dicarboxylic acids of the two key nylon precursors. This integrated approach seamlessly combined cadaverine production with efficient CO₂ capture and conversion, providing a groundbreaking pathway for utilizing CO₂ from biological processes in sustainable chemical manufacturing and advanced carbon management technologies.