|
(22-44) Rapid fluorescence techniques for the assessment of toxicological effects on bacterial populations within wastewater treatment plants. Forster, Scott*,1, Snape, Jason2, Lappin-Scott, Hilary1, Porter, Jonathan1, 1 School of Biological Sciences, Exeter, Devon UK2 Brixham Environmental Laboratory, Devon, UK ABSTRACT- Waste water treatment is one of the most important commercial biotechnological processes, yet the component bacteria (and their associated metabolic activities and chemical susceptibilities) are poorly understood. Fluorescent dye-based assays, combined with flow cytometric cell sorting, have been used to analyse bacterial communities from different stages in a typical plant, to determine bacterial group-specific activities during routine plant operation and when placed under chemical/toxicant stress. The novel dye hexidium iodide allowed assessment of Gram status. Differentiation between Gram positive and Gram negative waste water bacterial populations allowed simultaneous monitoring of the relative proportions of these two groups. Several direct fluorescence-based activity assays, including intracellular esterases, were used to monitor activated sludge populations after exposure to test compounds (including 3,5-dichlorophenol), for changes in population structure and population specific activities were monitored. Methods such as this, allowing rapid assessment of stress on bacteria responsible for waste breakdown may allow optimisation of treatment processes. The assessment of the effects of chemicals on specific bacterial groups will enable rapid pre-screening of effluent for toxicity prior to treatment, provide a method of post treatment assessment and will increase our understanding of microbial activity within treatment facilities. Moreover, this understanding will help maintain efficient process operation and could provide a method of assessing the effects of the final effluent on the natural microbiota in receiving water bodies. Key words: Flow Cytometry, Bacteria, Fluorescence, Stress |
