Synthesis and characterization of cross-linked lipase-metal hybrid nanoflowers on graphene oxide with increasing the enzymatic stability and reusability

In the current study, a purified lipase from Enterobacter sp. MG10 has been immobilized in three approaches, including lipase nano-flower (LNF), LNF/graphene oxide (GLNF), and cross-linked GLNF (CGLNF). The encapsulation yield (EY) and activity recovery (AR) were obtained in the range of 40.5 % to 81.0 % and 71.5 % to 132.2 % for lipase MG10, respectively. The best activity recovery was found (132.2 % for 0.02 mg ml(-1) enzyme) in the presence of 200 mM of Cu2+ for 72 h incubation at 4 degrees C. The CGLNF showed broader pH and temperature activities compared to free lipase. Moreover, the CGLNF displayed a 60 % improvement in lipase activity after 28 days of incubation, compared to free lipase. Remarkably, the K-m value of CGLNF was 0.980 mM toward the pNPP substrate, whereas the K-m value of free lipase was 17.11 mM at the same condition. Furthermore, the catalytic efficiency of CGLNF was 430.45 S-1 mM(-1), compared with 21.32 S-1 mM(-1) for the free lipase. The CGLNF showed 93 % efficiency in converting prosopis stephanina oil to biodiesel, whereas it found 63 % for the free lipase. Overall, these results showed the high potential of CGLNF nanobiocatalyst in synthetic biotechnology, especially in biodiesel production.

Automated summary

In the study, a purified lipase from Enterobacter sp. MG10 was immobilized using different methods, with CGLNF showing broader activity, higher efficiency, significantly reduced K-m value towards pNPP substrate, and high efficiency in converting prosopis stephanina oil to biodiesel. The results indicate the high potential of CGLNF nanobiocatalyst in synthetic biotechnology, particularly in biodiesel production.