Exogenous enzyme supplements to promote treatment efficiency in constructed wetlands
Authors: Shackle, V., Freeman C., Reynolds, B.,
Year of publication:2006
Journal: Science of the Total Environment, , Volume: 361(1-3), Pages: 18-24.
Publisher: Elsevier Science Bv; Po Box 211
Extracellular enzymes play a central role in the breakdown of organic pollutants. In wetlands constructed to treat waste-waters, supplementing the naturally occurring soil enzymes may result in faster pollutant removal, or breakdown of novel pollutants, but only if the added enzymes could retain their catalytic activity. In this study, the persistence of exogenous enzyme supplements was investigated. Adding cellobiohydrolase and -glucosidase to sterilised soil increased enzyme activity (range 375-4210%); although the increased activity began to decline after just 10-15 days. Thus, without an active microbial population, enhanced enzyme activity is unlikely to be long lived. However, with the naturally occurring soil microbes present to maintain the improved biodegradative capacity, cellobiohydrolase and beta-glucosidase additions created significant increases (range 173-530%) in activity and these persisted for more than 6 weeks. These findings therefore support the proposal that enzyme additions can enhance enzymic biodegradation processes, and suggest that this may be achieved primarily through a 'pump-priming' mechanism. (c) 2005 Elsevier B.V. All rights reserved.