INTERACTIONS BETWEEN GEMS AND INDIGENOUS MICROORGANISMS IN AQUATIC ECOSYSTEM

This study was conducted to elucidate the interaction and biotic effec t of indigenous microorganisms, especially micro animals and bacteria on prosperity and decay of GEMs (genetically engineered microorganisms ). Bacterial interaction means competition for substrate to grow betwe en GEMs and indigenous bacteria, and prey-predator interaction means e ffect of micro animals on survival of GEMs. So, it is considered that basic part of environmental effects of GEMs will be made clear with an alysi of these phenomena. Escherichia coli HB101/pBR325 as GEM, its ho st strain E.coli HB101, and Bacillus cereus MC as one of dominant spec ies of indigenous bacteria were supplied. As predator the micro animal s, Tetrahymena thermophila (ciliata, filter feeder) and Aeolosoma hemp richi (oligochaeta, detritus feeder) were supplied. The results obtain ed from this study can be concluded as follows: 1) GEMs showed few pot entials to beat their host strains in their growth competition; 2) pre dation of micro animals influenced equally GEMs and their host strains , and these microorganisms, such as bacteria, were expected to decreas e in environment; 3) floculation enabled GEMs to escape from predation of micro animals, but GEMs were not expected to survive long-term bec ause various predator species of micro animals exist in environment; 4 ) effect of micro animals, especially their predation, on survival of GEMs was so important that more practical research should be conducted ; 5) it suggests that the results obtained from this study can be used to establish regular guidelines for environmental release of GEMs suc h as bioremediation technologies. Copyright (C) 1996 IAWQ.