| 摘要: |
| 【目的】筛选能高效降解水稻秸秆的细菌，为水稻秸秆降解提供菌种资源，进而为改善生态环境、加快农业绿色低碳发展提供参考。【方法】以采自四川绵阳水稻田中的腐烂秸秆与土壤混合物以及羌王竹海中的腐烂竹节与土壤混合物为研究对象，以羧甲基纤维素钠为唯一碳源，采用稀释涂布平板法分离纯化细菌，经刚果红和苯胺蓝染色法以及滤纸条崩解试验筛选水稻秸秆降解菌，并检测其酶活性，综合水稻秸秆降解率和降解产物表征分析对其降解能力进行评估。【结果】以羧甲基纤维素钠为唯一碳源，采用稀释涂布平板法从腐烂水稻秸秆与土壤混合物及腐烂竹节与土壤混合物中分离得到63株细菌，且有4株细菌出现刚果红和苯胺蓝脱色圈，其中菌株QZ67脱色圈直径与菌落直径的比值最大，且滤纸崩解最彻底。生物学鉴定结果表明，菌株QZ67为台中类芽孢杆菌（Paenibacillus taichungensis）。在30 ℃、pH 8条件下发酵8 d，菌株QZ67的滤纸酶、木聚糖酶、锰过氧化物酶、木质素过氧化物酶活性均达到最高，分别为4 455.87，2 742.53，1 239.60和10 824.18 U/L，漆酶活性在发酵第10天达到最高，为2 160.49 U/L。菌株QZ67在30 ℃、pH 8、160 r/min条件下处理水稻秸秆30 d，相对降解率可达28.95%。红外光谱分析结果表明，在菌株QZ67作用下，水稻秸秆中的纤维素、半纤维素和木质素被降解。X光射线衍射分析结果表明，与未接菌处理相比，菌株QZ67处理30 d后水稻秸秆的结晶度明显降低。扫描电镜观察结果表明，菌株QZ67处理30 d后，水稻秸秆受到严重破坏，原本成束的维管束组织破裂成蜂窝状，基本组织变得松散细碎，水稻秸秆表面的蜡质 硅化层基本脱落。【结论】筛选获得1株具有较强纤维素、木质素降解能力的台中类芽孢杆菌（Paenibacillus taichungensis）QZ67，该菌株能有效降解水稻秸秆，有利于农作物秸秆循环利用，促进绿色农业可持续发展。 |
| 关键词: 水稻秸秆 生物降解 纤维素酶 木质素降解酶 秸秆利用 |
| DOI：10.13207/j.cnki.jnwafu.2025.03.010 |
| 分类号: |
| 基金项目:四川省“十四五”农作物及畜禽育种攻关计划项目（2021YFYZ0006）；国家重点研发计划项目(2021YFD2200504_1，2021YFD2200505_2) |
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| Screening of a rice straw degrading bacteria strain and its degradation effect |
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GUO Qi, LIU Rui, XU Gang, CAO Ying, HU Shanglian, ZHAO Bo
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Bamboo Research Institute,School of Life Science and Engineering,Southwest University of Science and Technology,Mianyang,Sichuan 621010,China
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| Abstract: |
| 【Objective】The research focused on studying the bacterial strains capable of efficiently degrading rice straw,with decomposed rice straw and soil mixtures from rice fields in Manyang,Sichuan,and decomposed bamboo nodes and soil mixtures from Qiangwang Zhuhai as research subjects,to provide bacterial resources for rice straw degradation,thereby improving the ecological environment and accelerating the development of green and low-carbon agriculture.【Method】The dilution coating plate method was used for separation and purification with sodium carboxymethyl cellulose as the sole carbon source.Bacteria capable of degrading rice straw were screened using Congo red and aniline blue staining methods and filter paper degradation tests.Their enzyme activities were measured,and their degradation ability was evaluated through a comprehensive analysis of rice straw degradation rate and characterization of the degradation products.【Result】A total of 63 strains of bacteria were isolated from sodium carboxymethylcellulose as the only carbon source,and 4 strains of bacteria exhibited Congo red and aniline blue decolorization circles.Among these,strain QZ67 displayed the most significant ratio of decolorization circle to colony diameter and the most complete disintegration of filter paper,subsequently being identified as Paenibacillus taichungensis.After fermentation at 30 ℃ and pH 8 for 8 days,the activities of filter paper enzyme,xylanase,manganese peroxidase and lignin peroxidase of strain QZ67 were measured at 4 455.87,2 742.53,1 239.60 and 10 824.18 U/L,respectively.The laccase activity reached its peak on the 10th day,at 2 160.49 U/L.Strain QZ67 achieved a relative degradation rate of 28.95% when treating rice straw for 30 days under the conditions of 30 ℃,pH 8,and 160 r/min.The results of infrared spectrum analysis revealed the degradation of cellulose,hemicellulose,and lignin in rice straw under strain QZ67.The X-ray diffraction analysis demonstrated a significant reduction in the crystallinity of rice straw after 30 days of treatment with strain QZ67 compared to untreated samples.SEM images exhibited severe damage to the rice straw following 30 days of treatment with strain QZ67,including honeycomb-like fractures in vascular tissue,loosening and fineness in primary tissue,and substantial disruption of the waxy silicification layer on the surface.【Conclusion】A bacterium with strong cellulose and lignin degradation abilities was selected,which effectively degraded rice straw,promoting the recycling of crop residues and facilitating the sustainable development of green agriculture. |
| Key words: rice straw biodegradation cellulase lignin-degrading enzymes straw utilization |
