| 碳氮比对干黄秸秆贮存过程及后续甲烷产量的影响 |
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| 引用本文： | 崔宪,张乐平,孙辉,温啸宇,郭建斌,董仁杰.碳氮比对干黄秸秆贮存过程及后续甲烷产量的影响[J].农业工程学报,2019,35(23):250-257. |
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| 作者姓名： | 崔宪 张乐平 孙辉 温啸宇 郭建斌 董仁杰 |
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| 作者单位： | 1. 中国农业大学工学院,北京 100083;,1. 中国农业大学工学院,北京 100083;,1. 中国农业大学工学院,北京 100083;,2. 中共中央党校研究生院,北京 100091;,1. 中国农业大学工学院,北京 100083;,1. 中国农业大学工学院,北京 100083; 3. 中国农业大学烟台研究院,烟台 264670; |
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| 基金项目： | 国家自然科学基金青年科学基金项目（51608523）;"十二五"国家科技支撑计划项目（2015BAD21B04） |
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| 摘 要： | 采取一定技术手段实现秸秆的有效贮存,是保证秸秆沼气工程全年稳定运行的前提。干黄秸秆因其处于可溶性碳源与氮源双重缺乏状态,对贮存过程会有一定影响。该文以干黄玉米秸秆为原料,通过补充可溶性碳源（蔗糖）与蛋白氮源（豆粕）调节秸秆初始C/N比后,分析其对秸秆湿贮存过程及后续甲烷产量的影响。当原料初始C/N比分别为30:1、25:1和20:1时。经60 d湿贮存试验结果表明,与仅添加蔗糖处理组相比,对贮存过程的pH值和干物质损失无显著影响（P>0.05）,但有效降低了半纤维素含量,乳酸产量分别提高了19.0%、22.2% 和31.7%;通过分析贮存前后的细菌群落多样性,结果表明,可提高秸秆湿贮存过程中有益菌（乳酸菌）的相对丰度,腐败菌（梭菌属）的相对丰度降至0%;对湿贮存前后原料进行产甲烷潜力测试,结果表明,与贮存前相比,累积甲烷产量分别提高3.9%、6.1%和10.8%。综上所述,通过补充可溶性碳源与蛋白氮源调节干黄秸秆C/N比,可改善干黄秸秆湿贮存过程的品质、稳定性和生物可降解性,并有效提高后续甲烷产量。研究结果可为秸秆沼气工程的贮存环节提供技术支撑。
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| 关 键 词： | 秸秆 发酵 甲烷 干黄玉米秸秆 湿贮存 厌氧发酵 C/N比 乳酸 |
| 收稿时间： | 2019/8/11 0:00:00 |
| 修稿时间： | 2019/9/13 0:00:00 |
Effects of adjusting C/N ratio of wilted maize straw on wet storage process and subsequent methane production |
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| Cui Xian,Zhang Leping,Sun Hui,Wen Xiaoyu,Guo Jianbin and Dong Renjie.Effects of adjusting C/N ratio of wilted maize straw on wet storage process and subsequent methane production[J].Transactions of the Chinese Society of Agricultural Engineering,2019,35(23):250-257. |
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| Authors: | Cui Xian Zhang Leping Sun Hui Wen Xiaoyu Guo Jianbin and Dong Renjie |
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| Institution: | 1. College of Engineering, China Agricultural University, Beijing 100083, China;,1. College of Engineering, China Agricultural University, Beijing 100083, China;,1. College of Engineering, China Agricultural University, Beijing 100083, China;,2. Graduate college, Party School of the CPC Central Committee, Beijing 100091, China;,1. College of Engineering, China Agricultural University, Beijing 100083, China; and 1. College of Engineering, China Agricultural University, Beijing 100083, China; 3. Yantai Research Institute, China Agricultural University, Yantai 264670, China; |
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| Abstract: | In northern China, large amounts of wilted maize straw as agricultural waste are produced annually due to the cropping system, harvesting method and so on. Straw-biogas-fertilizer has become one of the promoted utilization modes in major grain-maize producing areas of northern China. Straw is anaerobically digested to produce methane while digestate (effluent of anaerobic digestion process) is utilized as organic fertilizer. Wet storage is always reported as a preferred strategy to preserve energy crops for methane production. It can control microbial activity by a combination of an anaerobic environment and a natural fermentation of sugars by lactic acid bacteria on the crop to achieve lower dry matter loss compared to hay or open-air storage. However, the C/N ratio of wilted maize straw is generally 100-60:1, not only affects the microbial activity during storage, but also is not conducive to the anaerobic digestion. In this study, the effects of adjusting the C/N ratio of wilted maize straw by adding sucrose and soybean meal on the storage quality and subsequent methane production were studied. Wilted maize straw has been stored for 60 days with five treatments, including CK group (without additives), S group (only sucrose and water were added where the water-soluble carbon content and moisture content were adjusted to 3.5% and 65%, respectively), S-SM1 group (sucrose, soybean meal and water were added where, the water-soluble carbon content, C/N ratio and moisture content were adjusted to 3.5%, 30:1 and 65%, respectively), S-SM2 group (sucrose, soybean meal and water was added where the water-soluble carbon content, C/N ratio and moisture content were adjusted to 3.5%, 25:1 and 65%, respectively), S-SM3 group (sucrose, soybean meal and water were added where the water-soluble carbon content, C/N ratio and moisture content were adjusted to 3.5%, 20:1 and 65%, respectively). The results of 60-day wet storage experiment showed that, when the C/N ratio of wilted maize straw was adjusted to 30:1, 25:1 and 20:1, there was no significant effect (P>0.05) on pH value and dry matter loss but decreased the hemicellulose content compared to S group. At the same time, the lactic acid content was increased by 19.0%, 22.2% and 31.7%, respectively. The acetic acid content was increased by 20.0%, 30.0% and 30.0%, respectively. The butyric acid content was decreased by 55.0%, 65.0% and 65.0%, respectively. The relative abundance of lactic acid bacteria (Lactobacillus, Weissella, Enterococcus, Pediococcus) was increased by 13%, 45% and 63%, respectively. The relative abundance of Clostridium was reduced to 0%. The results of LEfse analysis showed that Lactobacillus and Cellulosimicrobium become biomarker when the C/N ratio of wilted corn straw was 20:1. The results of biomethane potential test showed that, the specific methane yield of CK group, S group, S-SM1 group, S-SM2 group and S-SM3 group was increased by 5.2%, 3.7%, 3.9%, 6.1% and 10.8%, respectively, compared with treatment groups before wet storage. Simulating the anaerobic digestion performance by the modifying Gompertz equation shows that adjusting the C/N ratio of straw can reduce the lag period. In summary, by adding water-soluble carbon and protein nitrogen to adjust the C/N ratio of wilted maize straw, it can effectively improve the storage quality, biodegradability and specific methane yield of wilted corn straw. In practical engineering applications, in order to reduce the cost of the project, it is appropriate to supplement other agricultural wastes with high nitrogen content for mixed storage. |
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| Keywords: | straw fermentation methane wilted corn straw wet-storage anaerobic digestion C/N ratio lactic acid |
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