秸秆预处理白腐菌株的筛选及其对厌氧发酵的影响

Screen of straw pre-treatment white-rot fungi strain and effect of straw pre-treatment on the anaerobic digestion process

农作物秸秆含有大量难降解的木质素,难于直接被厌氧微生物利用,降低了农作物秸秆的厌氧消化效率。该研究从8株白腐菌中筛选出1株产漆酶活力高的白腐菌株B-18,优化了该菌株的培养条件,确定适宜菌株B-18产漆酶的培养基为2%秸秆粉、2%蛋白胨、0.3%KH2PO4,0.15%MgSO4·7H2O,VB1 0.01g/L,1 000 mL蒸馏水、pH为5.0。利用该培养基进行B-18菌株培养,培养液中的漆酶活力单位为2.89 U。利用该菌株的液体培养物进行秸秆预处理,可促进秸秆中木质素的降解,这种作用加快了秸秆的厌氧发酵进程,可使秸秆产气时间提前4 d,产气量提高11.36%,容积产气率达到1.168 mL/(mL·d),原料产气率达到506.3 mL/g。该研究的进行对促进我国秸秆的沼气资源化利用具有重要的意义。

The straw contains a high content of lignin, which is difficult to utilize by anaerobic mi- croorganism. Using biological pretreatment straw could be degraded in the anaerobic digestion pro- cess easily. In this paper, a strain B-18 of white-rot fungus was screened from white-rot fungi and the culture condition was optimized. At the optimal culture condition, the enzyme activity was 2.89 U. The optimal conditions were listed as follow： straw powder of 2%,peptone of 2%, KH2PO4 of 0.3%, MgSO4·7H2O of 0.15% , VB1 of 0.01 g/L, pH of 5.0 and distilled water of 1 000 mL. The culture of B-18 was used to pre-treat corn straw. The results showed that the pre-treatment could destroy the complex structure of the lignin. After pre-treatment of B-18, the lignin content in the straw was re- duced from 15.2% to 8.6%. The degradation of lignin in straw enhanced the anaerobic digestion pro- cess. Compared to CK, the biogas production was improved 11.36% and the time of biogas produc- tion was advanced 4 days, the volume biogas production of corn straw was 1.168 mL/（mL.d） and the TS biogas productivity was 506.3 mL/g. This research is very important to the utilization of straw resource.