Abstract:Delignification is crucial in the energy utilization process of lignocellulose materials. In this study, efficiency of biological pretreatment of corn straw using different carriers of precolonized fungis, including Trametes versicolor, Trichoderma chromospermum, Trichoderma atroviride and combined fungi (T. versicolor + T. chromospermum, T. versicolor + T. atroviride) was investigated under unsterilized condition. Results showed that nearly negligible lignin degraded in the process of direct fungal pretreatment of unsterilized corn straw within 30d. It seems that inoculum of fungi cannot compete to the indigenous microorganisms of unsterilized corn straw, resulting in low lignin degradation rate. However, the degradation rates of 34.0%, 38.1%, 38.1%, 39.1% and 40.3% lignin in the sterilized corn straw were observed after 30d of cultivation by T. versicolor, T. chromospermum, T. atroviride, T. versicolor + T. chromospermum and T. versicolor + T. atroviride, respectively. To decrease the cost of sterilization, corn straw was pretreated by T. versicolor + T. atroviride and T. versicolor + T. atroviride with 1∶9, 1∶4 and 1∶1 of the ratio of precolonized carrier and substrate for 30d. During T. versicolor + T. chromospermum and T. versicolor + T. atroviride, pretreatment with an inoculum/substrate ratio of 1∶9, 1∶4 and 1∶1, the degradation rate of lignin were 30% ~ 40%. Therefore, precolonized carrier inoculum is an effective pretreatment method to decrease cost due to precolonized carrier can adjust the unsterilized condition and degrade lignin effectively.