发酵床陈化垫料纤维素降解真菌的分离及其堆肥效果研究

采用CMC-Na平板法和刚果红染色法从猪发酵床陈化垫料中分离到1株纤维素高效降解真菌M6。该菌株测序后的ITS基因序列与NCBI数据库进行BLAST比对,并构建系统发育树,该菌株初步鉴定为草酸青霉。优化固态发酵产酶工艺,确定最佳产酶条件:以麸皮+羧甲基纤维素钠为碳源,豆粕为氮源,初始pH值为6.0,接种量为10%,发酵温度为30℃、发酵时间为96h,羧甲基纤维素酶酶活最高可达1 446U·g~(-1),是优化前的2.31倍。堆肥试验结果表明:接种M6组和EM菌剂组均在第3d进入高温期(50℃),且高温分别维持了10d和6d;菌株M6组、EM组、对照组纤维素降解率分别为41.1%、38.8%、14.8%。因此,菌株M6组高温维持时间长、纤维素降解率高,在发酵床陈化垫料堆肥腐熟发酵中具有潜在的应用前景。

Isolation and Composting Efficiency of Cellulose-degrading Fungus from Litter Fermentation Bed in Pig Pan

A fungus,M6,that displayed a powerful ability to degrade cellulose was isolated from the waste fermentation beds at pig farms using the CMC-Na plate and Congo red staining methods.ITS sequence of the isolated strain was blasted with those from NCBI database,and the phylogenetic tree constructed to arrive at a preliminary identification for the fungus as Penicillium oxalate.Subsequently,an optimized enzyme-producing fermentation process on a solid medium inoculated with the isolated fungi was established.It included the application of bran and CMC-Na as the carbon source,soybean meal as the nitrogen source,pH 6.0 at the start,10％ inoculation rate,and fermentation at 30℃ for 96 h.The carboxymethyl cellulase activity of the material increased 2.31 times due to the optimization that reached 1 446 U · g-1.In a composting experiment on the fermentation beds inoculated with M6,EM or control,M6 and EM raised the bed temperature to greater than 50℃ on the 3rd day after start of fermentation,and maintained at the level for 10 d and 6 d,respectively.The cellulose degradation rate was 41.1％ with M6,38.8％ with EM,and 14.8％ with control.It suggested that,among the 3 tested fungi,M6 was most efficient on the waste treatment for pig farms.