堆肥中纤维素降解菌的筛选及复配菌降解性能研究

Screening of Cellulose Degrading Microorganisms in Composting Process and Study on Degrading Performances of Composite Strains

为加快堆肥过程中秸秆纤维素的降解速率,本研究从玉米秸秆堆肥中分离纤维素分解菌,并通过测定羧甲基纤维素酶(CMCase)活力、滤纸条崩解能力及兼容性,筛选出优良菌株,进而构建复合菌系,并对降解性能进行评价。结果共获得29株纤维素分解菌,对其中的高效菌株进行配伍,构建了6组复合菌系。除复合菌系F外,其他复合菌系的滤纸酶活力均显著高于单一菌株(P<0.05),尤以复合菌系B(xw1、xw3、xw8)、D(xw16、xw21、xw31)的酶活力最高,分别为22.8、20.4 U·mL^(-1),比其中的最强单菌株xw3、xw21高出58.3%、68.6%,且所产酶具有耐高温(40~55℃)性。复合菌系B、D培养5 d可将滤纸条崩解为糊状,10 d内对秸秆的降解率达24.5%、21.9%,较单菌株xw8、xw31增加9.4和4.7个百分点。经16S rDNA分子鉴定,复合菌系B由微杆菌属(Microbacterium sp.)、类芽孢杆菌属(Paenibacillus sp.)组成,复合菌系D由芽孢杆菌属(Bacillus sp.)、类芽孢杆菌属(Paenibacillu sp.)组成。本研究结果进一步丰富了纤维素降解菌种资源,为农业废弃物处理特别是堆肥接种剂的开发提供了借鉴。

To accelerate the degradation rate of straw cellulose during composting,strains that efficiently degrade cellulose were screened from corn straw compost by the Congo red staining method.The carboxymethyl cellulase(CMCase)activity,filter paper degradation effects,and compatibility of isolates were detected to screen the excellent strains that used to construct composite strains.Moreover,the degradation performances of composite strains were evaluated.The results showed that a total of 29 strains were isolated,among which the excellent strains were selected to construct six composite strains.The filter paper enzyme activities of compound strains were significantly higher than that of the single strain(P<0.05),except for community F.Especially,communities B(xw1,xw3,xw8)and D(xw16,xw21,xw31)had the highest enzyme activity of 22.8 and 20.4 U·mL^(-1),respectively,which were 58.3%and 68.6%higher than those of strains xw3 and xw21.And their enzymes were resistant to high temperature(40~55℃).The communities B and D could disintegrate the filter paper strip into paste after 5 d of fermentation,and they degraded 24.5%and 21.9%of corn straw after 10 d of fermentation,which were 9.4 and 4.7 percentage points higher than those of strains xw8 and xw31.16S rDNA identification showed that community B consisted of Microbacterium sp.and Paenibacillus sp.,while community D consisted of Paenibacillus sp.and Bacillus sp.The study further enriches the resources of cellulose-degrading strains and provides reference for the development of compost inoculants.