Method for degrading corn straws

A method for degrading corn straws is characterized by comprising the following steps: specifically mechanically crushing, sieving and drying the corn straws, then degrading lignin in the corn strawsby using immobilized laccase taking Cu2+ modified Fe3O4-NH2-PEI magnetic nanoparticles as carriers, recovering the immobilized laccase, boiling the degraded corn straws, then adding NaOH for washing,and adding cellulase for further degrading the cellulose. According to the method, the affinity between the immobilized laccase and a substrate is enhanced, the stability and the activity of the laccase in an application process are improved, thus, the degradation efficiency is improved, and the degradation rate of the lignin reaches 40.76% or above. Inhibition of the immobilized laccase and degradation products such as phenolic substances generated by degradation on the cellulase activity is eliminated, so that the cellulase activity is guaranteed, and the conversion rate of the cellulose isimproved, and reaches 46.85