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Lignin degradation in corn stover catalyzed by lignin peroxidase from Aspergillus oryzae broth: Effects of conditions on the kinetics

Fan, Yajuan, Zhang, Zhicai, Wang, Feng, Li, Jinhua, Hu, Kunya, Du, Zhuorong
Renewable energy 2019 v.130 pp. 32-40
Aspergillus oryzae, biomass, buffers, corn stover, hydrogen peroxide, lignin, lignin peroxidase, liquid state fermentation, models, oxidation, pH, renewable energy sources, sodium, temperature
In the present study, we aimed to explore the action mechanism of various factors on oxidation degradation reaction of lignin in the corn stover (CS) catalyzed by LiP from Aspergillus oryzae CGMCC5992 broth and optimize the oxidative degradation reaction conditions. The Michaelis-Menten (MM) analogous model suitable for oxidation degradation reaction of lignin containing two parameters, including the apparent maximum rate (μa,max) and apparent Michael constant (ka,m), was deduced. The reaction condition to obtain the maximum μa,max based on the orthogonal array designs was as follows: pretreatment temperature of 120 °C, pretreatment time of 5 min, reaction temperature of 30 °C, enzyme amount of 3.75 U/100 mL, 50 mmol/L sodium lactate-hydrochloric acid buffer of pH 1.5, H2O2 concentration of 20 mM and H2O2 amount of 1 mL, respectively. Under the optimized condition, the maximum μa,max achieved 1.68 (mg/mL)/min, and the ka,m was 0.37 mg/mL. The oxidation degradation of lignin in lignocellullosic biomass in a dilute solution system followed the MM analogous model. The study laid the foundation for improving pretreatment efficiency using a combination of Aspergillus oryzae CGMCC 5992 liquid-state fermentation and H2O2 treatment.