Development of an integrated process for the production of high-purity cadaverine from lysine decarboxylase

BACKGROUND Cadaverine is a natural polyamine that can replace fossil-derived hexamethylene diamine to produce bio-based polyamide. Despite huge developments in cadaverine bioproduction, an econo"mically attractive purification process is a highly important part of the production of high-purity cadaverine. RESULTS This study utilized l -lysine hydrochloride as a substrate for the production of high-purity cadaverine via a litre-scale integrated process incorporating fermentation, bioproduction, deprotonation, extraction and rectification. First, 8.24 U mg –1 lysine decarboxylase activity and 205 g L –1 cadaverine with a yield of 91.61% were achieved through the fermentation of low-cost industrial culture by engineered Escherichia coli and the bioproduction of cadaverine by lysine decarboxylase. Secondly, four integrated purification methods – deprotonation-evaporation, pH adjustment-deprotonation-evaporation, deprotonation-extraction-evaporation and deprotonation-extraction-rectification – were explored, and the conditions of each unit operation in the chosen method (deprotonation-extraction-rectification) were optimized. Then the optimized method was applied to a 2-L purification system, resulting in 99% purity of cadaverine with a yield of 87.47%. Furthermore, the n -butanol recovery ratio reached 91.25%, effectively avoiding the waste of resources and environmental pollution, and thus reducing purification costs. CONCLUSION The proposed experimental approach proves that this integrated process leads to the production of high-purity cadaverine. In the 2-L-scale integrated process, 358.64 g cadaverine of 99% purity was produced at a cost of US$3.99 (US$1.11 per 100 g), which is far below its market price (US$784.71 per 100 g). This integrated process provides a potential way for the industrial-scale production of bio-based cadaverine. © 2020 Society of Chemical Industry