title: Lignin degradation in corn stalk by combined method of H2O2 hydrolysis and Aspergillus oryzae CGMCC5992 liquid-state fermentation.
abstract: BACKGROUND
  Lignin peroxidase (LiP) is the primary enzyme responsible for lignin degradation. In our previous work, in order to shorten the pretreatment time and increase the lignin degradation, we have pretreated the corn stalk (CS) using a combination of Aspergillus oryzae CGMCC 5992 solid-state fermentation and H2O2 treatment.
  
  
  RESULTS
  In the present study, one-factor-at-a-time design and response surface design were applied to optimize the nutritional constituents for LiP production in liquid-state fermentation by A. oryzae CGMCC 5992 and the conditions for CS degradation by A. oryzae CGMCC 5992. The optimal medium included CS of 30 g/L, glucose of 4.6 g/L, sodium nitrate of 1.2 g/L, corn steep liquor of 1 g/L, yeast extract of 1.2 g/L, and vitamin B1 of 0.15 g/L. Under these optimal conditions, the LiP production reached its maximum of 652.34 U/L. The optimal condition for CS degradation included CS of 20 g, A. oryzae CGMCC 5992 broth of 50 mL, 1.5 % H2O2 solution of 80 mL, H2O2 flow rate of 0.4 mL/min, water volume of 240 mL (water/material ratio of 12:1), hydrolysis temperature of 39 °C, and hydrolysis time of 8 h. Before hydrolysis, CS and water were pretreated at 113 °C for 11 min. Under these optimal conditions, the sugar yield reached its maximum of 46.28 %.
  
  
  CONCLUSIONS
  Our newly developed method had great advantages in pretreatment of CS due to its quickness, convenience, safety, no special equipment and high sugar yield.Graphical abstractThe schematic diagram of corn straw hydrolysis.
authors.affiliation: Institute of Agro-production Processing Engineering, Jiangsu University, Zhenjiang, 212013 People's Republic of China ; Beijing Green Technology and Natural Biotechnology Co., Ltd., Beijing, 102300 People's Republic of China.
authors.forename: Zhicai
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Institute of Agro-production Processing Engineering, Jiangsu University, Zhenjiang, 212013 People's Republic of China.
authors.forename: Lili
authors.initials: L
authors.lastname: Xia
authors.affiliation: Institute of Agro-production Processing Engineering, Jiangsu University, Zhenjiang, 212013 People's Republic of China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: Institute of Life Science, Jiangsu University, Zhenjiang, 212013 People's Republic of China.
authors.forename: Peng
authors.initials: P
authors.lastname: Lv
authors.affiliation: Institute of Agro-production Processing Engineering, Jiangsu University, Zhenjiang, 212013 People's Republic of China.
authors.forename: Maxiaoqi
authors.initials: M
authors.lastname: Zhu
authors.affiliation: Institute of Agro-production Processing Engineering, Jiangsu University, Zhenjiang, 212013 People's Republic of China.
authors.forename: Jinhua
authors.initials: J
authors.lastname: Li
authors.affiliation: Institute of Life Science, Jiangsu University, Zhenjiang, 212013 People's Republic of China.
authors.forename: Keping
authors.initials: K
authors.lastname: Chen
keywords: Biofuel; Corn stalk; Fermentation; Hydrolysis; Lignin peroxidase; Sugar yield