Lignin degradation in corn stalk by combined method of H(2)O(2) hydrolysis and Aspergillus oryzae CGMCC5992 liquid-state fermentation

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 H(2)O(2) 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 B(1) 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 % H(2)O(2) solution of 80 mL, H(2)O(2) 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. [Figure: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13068-015-0362-4) contains supplementary material, which is available to authorized users.