基于改性热解有机物制备高水合性植物益生菌载体的研究

There is sufficient interest and demand to maintain a burgeoning pyrogenic carbon sector in many countries with agriculture, across latitudes. Development of the pyrogenic carbon sector in agriculture requires new products with value-added benefits that work more consistently across regions, such as using pyrogenic carbon as carriers for plant growth promoting bacteria. Pyrogenic carbon is more often hydrophobic, which will result in water stress for plant growth promoting bacteria and their nutrient acquisition. There is limited knowledge in the formation of hydrophobicity in pyrogenic and the modification processes. We propose a framework working on relationships between thermal pyrolysis parameters and hydrophobicity of pyrogenic carbon, comparisons in biological and chemical modification of hydrophobicity by using nuclear magnetic resonance (NMR)、specific surface area analyzer and pressure membrane. We selected 3 plant growth promoting bacteria, 2 of which have been spiked by green fluorescent protein. Microbial aging process is expected to occur during composting; OH generated by UV/H2O2 will be used to replace hydrophobic functional groups on pyrogenic carbon. We expect to produce a hydrophilic pyrogenic carbon as carriers for plant growth promoting bacteria. This research is expected to provide theoretical evidence to the formation of hydrophobicity in pyrogenic carbon, and supply technical support to the development of industrialization of thermal pyrolysis.

全球范围内热解技术产业化发展迅速，利用热解有机物替代泥炭作为植物益生菌载体提高农业经济价值是当前研究热点。但热解有机物多具疏水性，这种性质会导致热解有机物孔径中植物益生菌遭受水胁迫，或者不利于营养获取。当前关于热解有机物疏水性成因以及调节机制方面研究较少。因此，本项目研究热解有机物水合性与制备指标间关系，利用堆肥过程活跃微生物老化热解有机物，利用臭氧/双氧水产生的羟基自由基置换热解有机物表面官能基团，通过核磁共振、比表面积分析以及压力膜法比较生物及化学改性增强水合能力效果，选用3种植物益生菌（2种经绿色荧光蛋白标记）测定在改性与未改性热解有机物中丰度，评价高水合性热解有机物提高干旱胁迫条件下作为植物益生菌载体的效果。预期实验为热解有机物斥水性成因提供理论依据，同时为热解有机物产业化应用提供技术支持。

根据项目所提出的科学问题，本项目主要研究两部分内容：1）改性微米级热解有机物对蚯蚓存活曲线的影响；2）热解有机物表面水和性对于功能微生物群体的影响。项目选材包括不同水和性热解有机物，改性过程包括腐殖酸以及rhamolipid。土壤微生物群体的响应主要基于第二代测序技术以及下游生物信息学分析。主要研究结果表明：1）培养试验发现微米级热解有机物可能通过吸附蚯蚓皮肤引起水溶解氧的获取。这种过程可能进一步影响蚯蚓生存曲线；2）微米级热解有机物主要在环境水含量较低时对蚯蚓存活产生影响。热解有机物中所含有的重金属可能不是引起蚯蚓存活率降低的原因。另外，土壤酸碱度也不是引起蚯蚓存活曲线变化的因素；3）表面水和性可以将热解有机物进行分类；4）热解有机物表面水和性选择性吸附水和性氮源如尿素，并且对土壤微生物尤其细菌群体结构产生选择压力。本研究中水和性-微生物群体响应表明目前关于热解有机物对土壤微生物影响需要重点考量表面水和性。鉴于可能存在潜在消极作用，利用热解有机物作为土壤添加物仍需要综合考虑土壤微生物以及土壤动物的响应。