Highly active nanobiocatalysis in deep eutectic solvents via metal-driven enzyme-surfactant nanocomposite.

Metal-driven papain-surfactant nanocomposite (PA@MSNC), a novel soft nanobiocatalyst, was successfully prepared via one-pot self-assembly technique in aqueous solution for the biosynthesis of N-(benzyloxycarbonyl)-L-alanyl-L-glutamine (Z-Ala-Gln) dipeptide in deep eutectic solvents (DESs). The metal-driven self-assembly process generated PA@MSNC as nanospheres of ˜130 nm in diameter, with high protein loading and relative enzyme activity of 420 mg/g and 80% (4270 U/g protein), respectively. PA@MSNC showed high apparent substrate affinity and catalytic efficiency. The stability of PA@MSNC at high temperature and extreme pH was significantly higher than that of free PA. Catalysis efficiency for the biosynthesis of Z-Ala-Gln by PA@MSNC in choline chloride: glycerol reaction medium was 1.69-fold higher than that of free PA, achieving a high product yield of 75.7% within 4 h. PA@MSNC also showed better techno-economic performance. We propose that enzyme-surfactant nanocomposite via metal-driven dynamically reversible coordination interactions contribute simultaneously promotes catalytic flexibility and configurational stability. The generated PA@MSNC has potential practical implications for green synthesis of dipeptide in DESs.