再生水滴灌系统灌水器堵塞的微生物拮抗控制机理及调控模式

Reclaimed water drip irrigation is an important measure to alleviate the imbalance between supply and demand of water resources in China, however, which is vulnerable to the formation and attached biofilm in emitter consequently leads to clogging. clogging has become a bottleneck that restricted the application and popularization of this technology. Therefore, the objective of this project is to control the growth of microorganism in attached biofilm in drip irrigation emitters, and effectively solve the emitter bio-clogging with the help of microbial antagonistic technology. Two type of microbial antagonists with the function of rhizosphere promoting and biocontrol effects were used to control drip emitter bio-clogging and the emitter clogging characteristics, the key components of emitter clogging substance was monitored. The mechanism of antagonistic agents on biofilm microbial content, community structure and interaction would be revealed. Then, the composition, structure, biochemical metabolism and signaling pathways of extracellular polymers secreted by microorganisms would be identified after using of antagonists. Strive to reveal the whole process chain of molecular ecological mechanism for “microbial community structure/quorum sensing - gene expression - extracellular polymer secretion - biofilm removal” by application of microbial antagonistic technology. Establish a technology model for safe and more efficient application of microbial antagonist antimicrobial agents that comprehensively consider the clogging effect, technical cost, environmental safety and other multi-objective optimization of reclaimed water drip irrigation system emitters clogging control. The study aims of to provide theoretical and technical support for safe and efficient reuse of urban reclaimed water.

再生水滴灌技术是缓解水资源供需矛盾的重要举措。然而，再生水中大量的微生物、氮、磷等极易引起灌水器附生生物膜的形成，已成为制约该技术应用推广的瓶颈。传统加氯等控制方法往往存在长期应用效果不佳和土壤环境污染等问题，微生物拮抗是一种靶向控制生物膜中关键微生物生长的方法，前期研究表明两种根际促生拮抗菌剂有效地控制了灌水器生物堵塞。为此，本项目拟研究微生物拮抗菌剂对再生水滴灌系统灌水器堵塞特性、堵塞物质形成及关键组分的控制效应；摸清拮抗菌剂对生物膜微生物含量、群落结构以及互作关系的作用机理；明确拮抗菌剂施用后微生物分泌的胞外聚合物组成、结构及其生化代谢和信号分子传导路径。力求揭示微生物拮抗技术“微生物群落结构/群体感应-基因表达-胞外聚合物分泌-生物膜清除”的全过程链分子生态学机理，建立适宜再生水滴灌系统的微生物拮抗菌剂安全高效应用技术模式。旨在为城市再生水的安全、高效回用提供理论和技术支撑。

再生水滴灌技术是缓解水资源供需矛盾的重要举措。然而，再生水中大量的微生物、氮、磷等极易引起灌水器附生生物膜的形成，已成为制约该技术应用推广的瓶颈。传统加氯等控制方法往往存在长期应用效果不佳和土壤环境污染等问题，微生物拮抗是一种靶向控制生物膜中关键微生物生长的方法。基于16S高通量测序、X-ray diffraction、蛋白组学、糖组学等技术明确了拮抗菌剂对再生水滴灌系统内生物膜的去除能力和路径。结果表明施加BT后能有效去除已形成的污垢，污垢干重去除率达58.9% - 74.3%，管道流量恢复84.9%-92.0%。苏云金芽孢杆菌（BT）主要是通过诱导自身及污垢内的微生物分泌有机酸，直接溶解了碳酸钙等化学沉淀来清除灌水器内堵塞物质。碳酸钙的清除也导致生物-化学复合污垢的骨架发生崩塌，从而使得生物污垢，胞外聚合物发生了脱落。BT施加后生物膜内代谢过程、细胞过程、催化活性和BIRding MF蛋白的数量均显著下调，并通过拮抗作用显著改变了微生物群落的组成，进而影响蛋白质和多糖的组成。最终，促进了灌水器内堵塞物质的去除。通过对再生水滴灌系统施加解淀粉芽孢杆菌、枯草芽孢杆菌等拮抗菌应用模式研究发现，两周/次施加频率、施加浓度为108 CFU/mL是适宜的菌剂施加频率和浓度，并建议在滴灌系统堵塞程度下降至50%以内时施用。该研究为清除废水系统污垢难题提供了新的视角，对废水资源的回收高效利用具有潜在意义；为城市再生水的安全、高效回用提供了理论和技术支撑。