Detoxification of corn stalk pretreated with calcium hydroxide for true protein accumulation

Abstract

Alkaline pretreatment is essential in lignin degradation, but the inhibitors produced in this process affect microbial growth. To overcome the impacts of the phenolic compounds, detoxification was applied to corn stalk pretreated with calcium hydroxide.The results showed that ferulic acid degradation rate can reach 85.11% by laccase at the optimal conditions. Phanerochaete chrysosporium degraded most vanillin (77.19%) and p-hydroxybenzaldehyde (63.82%) but the degradation of ferulic acid (15.34%) was relatively weak. Laccase combined with Phanerochaete chrysosporium detoxified most of the phenolic compounds including 2- methoxy-4-vinylphenol (88.46%) and salicylic acid (58.13%) that hardly decompose alone after calcium hydroxide pretreatment in this study. These results inferred that Phanerochaete chrysosporium might generate some substance during the spore germination and growth period which may cooperate with laccase to decompose the phenolic compounds. After the fermentation of detoxified corn stalk by Neurospora crassa, the true protein content was increased by 2.73 times, and 21.17% lignin was degraded.