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| 秸秆降解放线菌的分离鉴定及其降解特性 |
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张晶1,2,3,钱玉婷1,曲萍1,2,3,曹云1,2,3,王秋君1,2,3,黄红英1,2,3*
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| (1.江苏省农业科学院 农业资源与环境研究所, 南京 210014;2.江苏省有机固体废弃物资源化协同创新中心, 南京 210095;3.农业农村部长江下游平原农业环境重点实验室, 南京 210014) |
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| 摘要: |
| 为获得优良秸秆降解放线菌，解析其秸秆降解特性，从森林土壤和秸秆堆肥环境中采集样品，采用富集培养方法筛选目标菌株，通过培养特征观察、生理生化鉴定和16S rDNA序列比对分析确定降解菌分类地位，结合扫描电镜技术分析降解过程中菌株对秸秆物理和化学性质的影响，考察培养温度、初始pH和氮源种类等培养条件对菌株降解秸秆的影响规律，以天然纤维素为底物测定菌株胞外纤维素酶活力动态变化。结果表明:1)本研究筛选获得的菌株ZY-2经鉴定为娄彻氏链霉菌(Streptomyces rochei)；2)Streptomyces rochei ZY-2在7 d内对秸秆的降解率可达29.23%，且能同时降解半纤维素、纤维素和木质素，3种组分的降解率分别为42.82%、47.05%和13.63%；3)菌株降解秸秆时，温度控制在35~45 ℃，初始pH控制在6.0~8.0，以有机氮为氮源生长时降解效果较好；4)菌株胞外能同时检测到内切纤维素酶和外切纤维素酶活性，生长前期内切纤维素酶活力较高，第4天达到峰值(0.12 U/mL)，而生长后期外切纤维素酶活力较高，第6天达到峰值(0.23 U/mL)。本研究筛选的菌株ZY-2是一株木质纤维素多组分降解放线菌，可为秸秆快速腐解提供优良菌种资源。 |
| 关键词: 秸秆降解 菌株鉴定 木质纤维素 纤维素酶 |
| DOI：10.11841/j.issn.1007-4333.2023.12.07 |
| 投稿时间：2023-04-06 |
| 基金项目:江苏省农科院资环所2022年度青年联合创新项目(ZCX(2022)22) |
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| Screening, identification and degradation characteristics of one straw degrading actinomycete strain |
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ZHANG Jing1,2,3,QIAN Yuting1,QU Ping1,2,3,CAO Yun1,2,3,WANG Qiujun1,2,3,HUANG Hongying1,2,3*
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| (1.Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China;2.Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing 210095, China;3.Key Laboratory of Agro-Environment in Downstream of Yangtze Plain, Ministry of Agriculture and Rural Affairs, Nanjing 210014, China) |
| Abstract: |
| The purpose of this study was to obtain excellent straw degrading actinomycetes and analyze their degradation characteristics. Target strains were screened by enrichment culture method with samples collected from forest soil and straw compost environment. The classification status of degrading strain was determined by observation of culture characteristics, physiological and biochemical identification, and comparative analysis of 16S rDNA sequence. Combined with scanning electron microscope technology, the changes of physical and chemical properties of straw during degradation were analyzed. The effects of culture temperature, initial pH and nitrogen source type on straw degradation were investigated. The dynamic changes of extracellular cellulase activity were measured with natural cellulose as substrate. The results showed that: 1)The strain ZY-2 screened in this study was identified as Streptomyces rochei; 2)The straw degradation rate of Streptomyces rochei ZY-2 could reach 29. 23% within 7 days, and the degradation rates of hemicellulose, cellulose and lignin were 42. 82%, 47. 05% and 13. 63%, respectively; 3)The optimal straw degradation conditions of ZY-2 were as follows: incubation temperature 35-45 ℃, initial pH 6. 0-8. 0, organic nitrogen as nitrogen source; 4)The strain could secrete both endo- and exo-cellulase. Endo-cellulase activity was higher at the early stage of growth and reached the peak(0. 12 U/mL)on the 4th day, while the exo-cellulase activity was higher at the late stage of growth and reached the peak(0. 23 U/mL)on the 6th day. In conclusion, the strain ZY-2 screened in this study is a multi-component lignocellulose degrading actinomycete, which can be used as excellent bacterial resource for the rapid decomposition of straw. |
| Key words: straw degradation strain identification lignocellulose cellulase |
