Article title: Ligninase-mediated Transformation of 4,4’-Dibromodiphenyl Ether

Journal name: Environmental Science and Pollution Research

Authors:Yiping Feng \and Liang Mao \and Yijun Chen \and Shixiang Gao

Address:Yiping Feng \and Liang Mao \and Yijun Chen \and Shixiang Gao\ at State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China

The e-mail address, telephone and fax numbers of the corresponding author(Shixiang Gao): \ Tel.: +86 -25 -89680359, Fax: +86 -25 -89680359 \\E-mail:

Supplemental Material:

Content:
SM-1 / Introduction / Schematic depiction of LiP catalytic cycle(Fig. SM-1)
SM-2 / Resultsand Discussion / The discussion of Enzymatic reaction kinetics (Fig. SM-2)
Effect of VA and NOM(Fig. SM-3)and Table SM-1

Introduction

Fig. SM-1:

Fig. SM-1 Schematic depiction of LiP catalytic cycle. The steps 1, 2 and 3 (in red) represent the catalytic cycle and the steps 4 and 5 (in black) denote LiP inactivation via LiPIII and step 6 (in blue) represent the mitigation of LiP inactivation in the presence of VA. (adapted from Mao et al.2010)

Results and Discussion

Enzymatic reaction kinetics

The Michaelis-Menten equation shows the relationship between initial velocity of enzymatic reaction and substrate concentration (Fig.SM-2.A). The simplified form can be described as:

,

where Vis the initial reaction rate for each initial substrate concentration and Kmis the substrate’s Michaelis constant, Vmaxcorresponds to the maximum reaction rate which can be achieved when substrate concentration is sufficiently to saturate all available enzymes. Usually, the conversion form of Michaelis-Menten equation, the Lineweaver-Burk equation:

,

is applied to derive Km andVmax. 1/V plot of 1/[S], obtained a straight line (Fig. SM-2.B). The absolute value of straight line intercept with the x-axis was 1/Km; and 1/Vmax was straight line intercept with the y-axis.

Fig. SM-2:

Fig. SM-2. Michaelis-Menten curves (A) and Lineweaver-Burk equation (B) for LiP-catalyzed BDE 15 reactionsExperiment conditions: [BDE 15] = 381.1 nM; [LiP] = 0.047 U mL-1, [H2O2] = 0.2 mM, [VA] = 2 mM, pH = 4 (10-mM CPBS), Reaction time = 40 seconds. Error bars represent standard deviations (n=3).Without NOM (in balck), with 8.41 mg (TOC) L-1NOM (in red).

Effect of VA and NOM on LiP-mediated BDE 15 transformation

Fig. SM-3:

Fig.SM-3. Rate of VA conversion by LiP in reaction system containing NOM at various concentration.

Experiment conditions: [NOM] = 0, 4.14, 8.41 and 12.68 mg (TOC) L-1. [LiP] = 0.031 U mL-1, [H2O2] = 0.2 mM, pH = 4 (10-mM CPBS), [VA] = 2 mM.

Table SM-1:

Kinetics parameter of BDE 15 transformation in LiP-mediated reaction system that containing VA and/or NOM. Experiment conditions: [LiP] = 0.047 U mL-1, [H2O2] = 0.2 mM, pH = 4 (10-mM CPBS), [VA] = 2 mM, [NOM] = 8.41 mg (TOC) L-1. Error bars represent standard deviations (n=3).

Treatment groups / k0 (min-1)a / y=k0x+b / R2
without VA or NOM / -2.02±0.27b / Y=-2.02x+341.26 / 0.97
with NOM / -1.99±0.16b / Y=-1.99x+342.22 / 0.97
with VA / -5.45±0.28 / Y=-5.45x+340.28 / 0.99
with VA and NOM / -4.19±0.05 / Y=-4.19x+346.83 / 0.98

aPseudo-first-order kinetic rate constant for LiP-mediated transformation of BDE 15.

bNo difference value was significant between the two (p < 0.05), and for others,differences between treatment groups were considered statistically significant at p < 0.05.

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