Eradication of Microbial Contamination in Metal Working Fluids

在许多制造过程中，使用金属加工液以确保降低刀具磨损和工件质量。据估计，全球每年消耗的金属加工液超过5亿加仑。然而，微生物污染是这些流体降解的一个重要因素，导致设备的生物结垢和腐蚀，金属加工液的降解，产品质量的危害，并构成职业安全风险。一旦金属加工液受到微生物污染，去除细菌就是一项艰巨的任务。残留的细菌可以迅速重新滋生，即使经过仔细的清洁和充电程序也是如此。工作液系统中不可接触区域内的生物膜可能是清洗后快速重新繁殖的原因。生物膜是附着的微生物群落，其功能依赖于复杂的社会相互作用。群体感应为生物膜细胞提供了沟通和集体控制群体行为的手段。该奖项支持关于抑制生物膜形成的法定人数猝灭策略的基础研究。研究结果有助于提高金属加工液的可持续性，减少浪费，并有助于限制职业暴露于金属加工液中潜在的致病菌。第一个研究目标是建立法定猝灭剂浓度与该试剂消除生物被膜效果之间的关系。一套法定猝灭剂(即大黄素、酰基酶和α-淀粉酶)将在八行十二列的测试矩阵中进行研究。从制造商对浮游生物的建议剂量开始，浓度将有所不同。将使用在金属加工液中生长的生物膜生物模型(即荧光假单胞菌和枯草芽孢杆菌)。使用微板吸收光谱生物膜去除试验，通过该试剂对生物膜去除的最小抑制浓度来评价该制剂对生物被膜去除的效果。第二个研究目标是确定消除生物被膜的行动模式。目前尚不清楚法定人数猝灭剂是阻止了生物膜在表面的初始建立，还是破坏并去除了已经建立的生物膜。使用共聚焦激光显微镜和Imaris和Metamorph图像分析软件，将使用滴流反应器实时分析生物膜的形成和破坏。

In many manufacturing processes, metal working fluids are applied to ensure reduced tool wear and workpiece quality. Worldwide, more than half a billion gallons of metal working fluids are estimated to be consumed annually. However, microbial contamination is a significant factor in the degradation of these fluids, causing biofouling and corrosion of equipment, degradation of metal working fluids, imperilment of product quality, and posing occupational safety risks. Once metal working fluids are microbially contaminated, removing bacteria is a difficult task. Residual bacteria can quickly repopulate, even after meticulous cleaning and recharge procedures. Biofilms within the inaccessible regions of a working fluid system are likely responsible for the rapid post-cleaning repopulation. Biofilms are attached microbial communities whose function depends on complex social interactions. Quorum sensing provides the means for biofilm cells to communicate and collectively control group behavior. This award supports fundamental research on quorum quenching strategies to inhibit biofilm formation. Research results can help to increase the sustainability of metal working fluids, reduce waste, and help limit occupational exposure to potentially pathogenic bacteria inhabiting metal working fluids.The first research objective is to establish the relationship between the concentration of quorum quenching agent and the efficacy of the agent on biofilm eradication. A suite of quorum quenching agents (i.e., emodine, acylase, and a-amylase) will be studied in a testing matrix of eight rows and twelve columns. The concentration will be varied beginning with the manufacturer's suggested dosage for planktonic organisms. Model biofilm organisms (i.e., Pseudomonas fluorescens and Bacillus subtilis) grown in a metal working fluid will be used. The efficacy of an agent on biofilm eradication will be evaluated by the agent's minimal inhibition concentration for biofilm removal using a microplate absorption spectroscopy biofilm removal assay. The second research objective is to determine the action mode of biofilm eradication. It is unknown whether the quorum quenching agents prevent the initial establishment of biofilms on a surface or they disrupt and remove an already established biofilm. Using confocal laser microscopy and Imaris and MetaMorph image analysis software, biofilm formation and disruption will be analyzed in real-time using a drip flow reactor.