The lysine decarboxylase and cofactor PLP were co-immobilized successfully.
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One-step immobilization and purification of lysine decarboxylase was achieved.
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PEI improved the stability and activity of lysine decarboxylase.
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A microreactor was fabricated for cadaverine bioconversion continuously.
Abstract
Cadaverine (1,5-diaminopentane) has widespread applications in industry, agriculture and medicine. Cadaverine can be biotransformed from l-lysine by lysine decarboxylasey which is a pyridoxal 5′-phosphate (PLP)-dependent enzyme. Herein, barium alginate microspheres were fabricated by electro-dripping and employed as immobilized metal ion affinity chromatography matrix to purify and immobilize engineered lysine decarboxylase CadA-EK. Besides, polyethyleneimine (PEI) was employed for co-immobilizing PLP and enzymes (cCadA-EK-PEI/PLP). The cCadA-EK-PEI/PLP can produced 184.53 g/L cadaverine with yield of 90.03% in 2 mol/L lysine solution. And the stability of co-immobilized CadA-EK was 1–4 times higher than that of iCadA-EK + PLP in environmental factors, and the catalytic efficiency kcat/Km was increased by 3.4-fold. Furthermore, a continuous flow microreactor with the co-immobilized enzymes and cofactors was developed to catalyze lysine, with 14.28 g/(L·h) productivity of cadaverine, which displayed great potential for cadaverine biosynthesis. This work provides alternative strategy for the one-step purification and co-immobilization of enzyme and cofactor.
