Table 1.
The CCD design and the observed responses for MG decolorization.
Fig 1.
Response surface plots of the interaction between different variables.
(A) Concentrations of enzyme and MG. (B) Concentration of enzyme and time. (C) Concentration of MG and time.
Table 2.
ANOVA for the response surface quadratic model.
Fig 2.
UV-visible spectra of MG before and after treatment with LacA.
Fig 3.
LC-TOF MS analysis of MG degraded by LacA.
(A) MG control. (B) MG degradation after 60 min. (C) MG degradation after 180 min.
Fig 4.
The mass spectra of MG and its degradation products.
(A) MG, m/z 329.20 (retention time 7.23 min). (B) desmethyl MG, m/z 315.18 (retention time 7.01 min). (C) didesmethyl MG, m/z 301.17 (retention time 6.84 min). (D) tridesmethyl MG, m/z 287.16 (retention time 6.65 min). (E) tetradesmethyl MG m/z 273.14 (retention time 6.53 min). (F) (dimethyl amino-phenyl)-phenyl-methanone, m/z 226.12 (retention time 9.14 min). (G) (methyl amino-phenyl)-phenyl-methanone, m/z 212.11 (retention time 8.48 min). (H) (amino phenyl)-phenyl methanone, m/z 198.09 (retention time 7.80 min).
Fig 5.
Proposed mechanism of LacA-mediated MG degradation.
i, pathway I; ii, pathway II.
Table 3.
Phytotoxicity study of MG and the degradation products.