Immobilization of laccase in N-doped carbon hollow spheres/chitosan composite film for electrochemical detection of kraft lignin

In this article, N-doped carbon hollow spheres (NCHS) were successfully synthesized through fastly and facilely thermally treating poly(o-phenylenediamine) (PoPD). The NCHS and chitosan composite (NCHS/Chi) provided a novel biosensing matrix for the immobilization of laccase due to its good conductivity, high stability and good biocompatibility. Based on this, an amperometric biosensor by entrapping laccase into the NCHS/Chi composite for industrial kraft lignin has been fabricated. Results displayed that the biosensor had high sensitivity and long-term stability in the presence of the mediator (2,2′-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS2−)) at pH 6.0. For practical applications, the methods used for the preparation of the biosensor should be simple, rapid, and reproducible.