牛粪高温堆肥过程中木质纤维素降解及相关生物学特性研究

为探明木质纤维素在堆肥过程中的降解情况，以牛粪和砻糠为原料，进行为期112 d的小型堆肥试验，在不同堆肥阶段测定物料的木质纤维素含量及相关降解酶活性，并在高温和降温阶段从物料中分离鉴定纤维素降解菌。结果表明，堆肥过程中物料的纤维素与半纤维素含量逐步降低，总降解率分别为5626%和6147%；而木质素的相对含量略有增加；与木质纤维素降解相关的纤维素酶和木聚糖酶的活性均呈现先增高后降低的趋势，其酶活均在第42天达到峰值，分别为8575 μg glucose·g-1·DW·h-1 和16565 μg·reducing sugar·g-1·DW·h-1，而β 葡聚糖苷酶的活性在22～42 d之间维持在较高水平(279～330 μmol pNPG·g-1·DW·h-1)；此外，在堆肥的高温和降温腐熟阶段均分离并鉴定出Pseudoxanthomonas，Bacillus，Paenibacillus，Ureibacillus和Geobacillus等5个属的可培养高温纤维素降解菌。

Lignocelluloses degradation and related biological characteristics during thermophilic composting of cow dung

In order to improve the understanding of lignocelluloses degradation during composting， a small scale composting for 112 d was carried out with cow dung and rice chaff as raw materials. The contents of lignocelluloses and the enzyme activities of cellulase， xylanase and β glucosidase were determined， and microorganisms related to cellulose degradation were isolated during the composting process. It was shown that the degradation rates of cellulose and hemicellulose after composting were 5626% and 6147%， respectively， but the content of lignin increased at last. Activities of cellulase and xylanase both increased firstly and reached the maximum value (8575μg glucose·g-1 DW·h-1 and 16565 μg reducing sugar·g-1 DW·h-1, respectively) at the 42nd day， and then decreased till the end of composting. However， the activity of β glucosidase stayed at a relatively high level (279-330 μmol pNPG·g-1 DW·h-1) from day 22 to 42. Microorganisms including Pseudoxanthomonas， Bacillus， Paenibacillus， Ureibacillus and Geobacillus were isolated and identified related to the thermopilic cellulose decomposing process．