Enhanced Degradation of Corn Straw for Methane Production Via a Novel Composite Fungal Agent

Abstract

<b>Highlights</b> <list list-type=bullet><list-item> A novel composite fungal agent was used to pretreat straw. </list-item><list-item> Scanning electron microscopy showed that the lignocellulosic structure was obviously damaged by the composite fungal agent. </list-item></list> <list list-type=bullet><list-item> The methane yield per g of straw was 51.7% higher than that of the untreated group. </list-item><list-item> The T80 (time taken to reach 80% gas production) was shortened by 31.8%. </list-item></list> <b>Abstract</b>. In this study, the fungal agent consisting of Phanerochaete chrysosporium (Pc) and Trametes gallica (Tg) were studied. The effects pretreatment temperature, pretreatment time, fungi liquid addition, and fungi ratio had on the degradation of corn straw were studied. The anaerobic methane production performance of untreated and composite fungal agent treated corn straw was evaluated. To maximize the gas production, the response surface method was used to determine the optimal parameters of the pretreatment of straw by the composite fungal agent, The proportion of the fungi was Tg: Pc= 3:1, and the amount of fungi added was 6%. The pretreatment temperature was 28.5℃ and the pretreatment time was 11 d. The cellulose content in the corn straw pretreated by this condition was (29.6±1.4)%, the hemicellulose content was (22.0±1)%, the lignin content was (8.9±0.6)%, and the gas production after pretreatment was (232.9±4.8) mL/gstraw, the gas production was increased by 51.7% compared with the untreated control group, and the T80 (time taken to reach 80% gas production) was shortened by 31.8%. In addition, the degradation effect of composite fungal agent pretreatment under scanning electron microscope (SEM) was observed. The SEM showed that the bundle structure of cellulose was obviously damaged, indicating that the composite fungal agent had a significant effect on straw degradation.