One-pot synthesis of arginine decarboxylase@ZIF-8 using intrinsic pyridoxal 5′-phosphate cofactor for agmatine production

Agmatine is an important basic drug and nutritional supplements, which exhibits significant physiological activities. Traditional methods, such as whole-cell catalysis, require substantial pyridoxal 5′-phosphate (PLP) addition, which accounts for 15 % of production costs. In this study, we utilized purified arginine decarboxylase (AdiA-M2) that leverages the intrinsic PLP cofactor, without the need for additional PLP supplementation, and ZIF-8 was employed to enhance the pH tolerance. The successful incorporation of AdiA-M2 into the ZIF-8 structure was confirmed through scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The immobilized arginine decarboxylase demonstrated markedly enhanced performance under alkaline conditions, along with improved thermal stability and storage activity compared to its free enzyme counterpart. Specifically, the immobilized AdiA@ZIF-8 system achieved an initial conversion rate of 95.16 %, after five recycles the titer attained 266.69 g/L without the extra PLP addition, which is 1.67 times higher than the best current production approach. The adopted enzyme-catalysis system eliminated the need for additional cofactors, thereby lowering costs and providing valuable insights for the industrial production of agmatine.