碳氮比对猪粪和稻秆协同生物降解的影响

Effects of carbon to nitrogen ratio to synergistic degradation of pig manure and rice straw

农业废弃物猪粪和稻秆产量巨大,因缺乏有效的处置方式,从而造成了巨大的污染,阻碍了现代农业的可持续发展。本研究以猪粪和稻秆的协同高效降解为研究导向,首次采用纤维素分解复合菌系预处理技术进行协同降解。通过考察碳氮比为10∶1、13∶1、16∶1和19∶1等4个梯度下的猪粪和稻秆混合物协同降解情况,并测定不同碳氮比不同培养时间下降解液的关键参数,探讨了不同碳氮比条件下复合菌系对农业废弃物协同降解效果的影响。结果表明,该菌系在碳氮比为16∶1、固形物含量为6%、接种量为10%的条件下于55℃下培养96 h,对猪粪和稻秆混合物的降解效果最佳。在此条件下其失重率高达26.2%,降解过程中的关键酶——滤纸酶和羧甲基纤维素酶(CMC酶)酶活可分别达到3.2和10.8 IU。该复合菌系在对猪粪和稻秆混合物协同降解过程中除了添加少许氯化钠外,无需再额外添加其他营养物质,展现出了良好的实际应用前景,可进一步为其他种类的农业废弃物的高效生物处置提供一定的理论依据。

Agricultural waste in the forms of pig manure and rice straw occur in huge amounts every year. This has caused serious environmental pollution and hindered the development of modern sustainable agriculture due to the lack of an effective disposal technique. The synergistic and effective degradation of pig manure and rice straw was regarded as the research direction in this study. A pretreatment technology using a cellulolytic microbial consortium was used to synergistically degrade the two wastes for the first time. The synergistic degradation of pig manure and rice straw with four carbon-to-nitrogen ratios（ 10 ∶ 1,13 ∶ 1,16 ∶ 1,and 19 ∶ 1） was investigated.Meanwhile,by measuring the key degradation parameters of the degradation liquid with different carbon-to-nitrogen ratios after different incubation times,the synergistic degradation effect of agricultural wastes by this microbial consortium under different carbon-to-nitrogen ratios was investigated. The results indicate that this consortium has optimum effect for degradation of a mixture of pig manure and rice straw,when the incubation conditions are：carbon-to-nitrogen ratio 16 ∶ 1,solid content 6%,inoculum volume 10%,and incubation at 55 ℃ for 96 h. At that time,the weight losing ratio could reach 26. 2%,and the activities of key enzymes（ filter paper enzyme and carboxymethyl cellulose enzyme： CMC-ase） could reach 3. 2 and 10. 8 IU,respectively. In addition,no extra nutrients except for a small amount of Na Cl would need to be added to the cultures of mixed pig manure and rice straw when being synergistically degraded by this microbial consortium. This work provides a favorable prospect for practical application,and provides a clear theoretical basis for effective biological disposal of other kinds of agricultural waste.