Immunological methods for the study of Zoogloea strains in natural environments

Since Zoogloea ramigera has been considered to be important in aerobic wast ewater treatment, we have evaluated several methods for detecting and enume rating Z. ramigera in water and wastewater samples. Indirect immunoassay me thods for the detection of Zoogloea strains were developed using polyclonal antibodies against the cells or the isolated exocellular polymer (EP) of t he neotype Zoogloea ramigera strain 106 (ATCC 19544). The primary antibodie s reacted with the cells and the exopolymer associated with finger-like zoo gloeal projections, but not with other bacteria from natural samples. These antibodies allowed detection of Z. ramigera in environmental samples. Scan ning electron microscopy (SEM) was used to show that the cells and the exoc ellular polymer of naturally occurring zoogloeal projections are antigenica lly and structurally related to those of Z. ramigera 106. Both immunologica l procedures and probes complementary to regions on the 16S rRNA could dete ct Z. ramigera in natural samples but the immunological procedures were eas ier to use. RT-PCR was also used to detect Z. ramigera in natural samples. These methods were also used to identify Z. ramigera in biofilms that devel oped over wastewater samples as part of an MPN procedure that was used to q uantitate Z. ramigera at different stages of the wastewater treatment proce ss and in different lakes. Z. ramigera could be found in all stages of wast ewater treatment processes, from raw wastewater to chlorinated effluent. Th e highest concentration of Z. ramigera was found in the mixed liquor stage of the a wastewater treatment plant. Additionally, Z. ramigera was found in all eutrophic and mesotrophic lakes and in some oligotrophic lakes. (C) 20 01 Elsevier Science Ltd. All rights reserved.