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Extracellular‐enzyme activity in trout‐farm effluents and a recipient river
Author(s) -
Brown S E,
Goulder R
Publication year - 1996
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1046/j.1365-2109.1996.t01-1-00818.x
Subject(s) - biology , trout , extracellular , effluent , fishery , enzyme , enzyme assay , ecology , microbiology and biotechnology , fish <actinopterygii> , biochemistry , environmental engineering , engineering
Extracellular‐enzyme activity (i.e. external to cytoplasmic membranes) increased in water flowing through trout farms. Directly counted bacteria also increased, but partitioning of extracellular‐enzyme activity in outflow water by 0.2 μm filtration showed that a substantial proportion was often free rather than cell‐associated, and might have originated as free enzymes released by enriched sediments or by fish. Discharges from four trout farms caused marked increases in extracellular‐enzyme activity along a 13‐km length of river, which were sometimes sufficient to swamp native enzyme activity. The pollutant enzymes might have facilitated bio‐purification in the river. Artificially increased extracellular‐enzyme activity in the river was accompanied by increase in bacterioplankton and phytoplankton chlorophyll, but partitioning showed that most of the increases in leucine aminopeptidase and phosphatase activity were due to free enzymes. In contrast, increase in β‐glucosidase activity was perhaps more associated with bacterial and/or algal cells.