Effect of Triton X-100 on the removal of aqueous phenol by laccase analyzed with a combined approach of experiments and molecular docking

Abstract

Effects of Triton X-100 on the removal of aqueous phenol catalyzed by laccase were studied. The optimal concentration of Triton X-100 was 155 μM to improve phenol removal when the concentrations of phenol and laccase were 50 mg/L and 0.05 mg/mL, respectively. Laccase activity was increased with Triton X-100 at concentrations from 31 to 930 μM and the highest increase was about 17% by 930 μM Triton X-100. The removal efficiencies of phenol with 155 μM Triton X-100 were 1.2, 1.6, 3.4, 4.5, and 5.7 fold those of the control after 6h when the initial concentrations of phenol were 50, 100, 200, 400 and 600 mg/L, respectively. Molecular docking method was used to analyze the interactions between laccase and substrates. Docking results showed that phenol formed hydrogen bonds and hydrophobic interactions with laccase, whereas Triton X-100 formed hydrophobic interactions with laccase, which may increase the laccase activity and enhance phenol removal. The reaction of phenol removal was also characterized using UV spectra. The results indicated that the presence of low concentrations of Triton X-100 for phenol removal catalyzed by enzymes may be an alternative to the present phenol removal processes in water treatment or remediation.