Antibody recognition of an 18 kDa protein possibly involved in phosphate removal by activated sludge

Phosphate in wastewater effluent is implicated in eutrophication of water r eserves. Enhanced biological phosphate removal by activated sludge is attri buted to polyphosphate accumulating bacteria, which release phosphate durin g anaerobiosis and reincorporate it during aerobiosis. The aim of the study was to investigate whether the process of phosphate removal by activated s ludge could be probed immunochemically. Antigen preparations from the aerob ic and preceding anoxic zones of a phosphate removing system contained inta ct and lysed bacterial cells. Neither conventional nor subtractive immunisa tion strategies, the latter employing cyclophosphamide to immunofocus on un ique epitopes in the zones, provided antibodies capable of distinguishing b etween these Zones. However, a putatively protein-directed monoclonal antib ody could distinguish between the aerobic zones of two activated sludge sys tems, differing only in phosphate removal ability: immunoblot showed Eve di screte bands, with molecular weights appearing to be multiples of 18 kDa, u nique to the system successful at phosphate removal. (C) 2000 Elsevier Scie nce Ltd. All rights reserved.