Effects of Physiological Variables on Growth of Organohalide Respirers

Abstract

There is a group of bacteria that is capable of the reductive dechlorination of chlorinated compounds, such as PCEs, by energetically using the chlorines in the compounds as terminal electron acceptors when oxygen is not present. Most experiments are conducted with the basic growth conditions that are needed to grow Dehalococcoides spp., because of its ability to completely dechlorinate PCE compounds to ethane, and other similar organohalide respiring bacteria and the terminal electron acceptor, the pollutant, is what is being tested and changed, but there has not been much research on optimizing or testing the growth conditions of these organohalide respiring bacteria. For this particular experiment, three different variables were changed: salinity, carbon source, and temperature, as well as looking at the differences between the effects of adding oak or pine based organochlorines. Methanol seems to be a better carbon source to use when trying to enrich organohalide respiring bacteria quickly and the carbon source that seemed to enrich the bacteria the least was acetate. Also, the temperature of 30°C seems to be the best temperature in which to enrich the bacteria as well, shown both by the results here and by the studies observed. There is a fair amount of OTUs present that are unique to the microcosms that were grown at 45°C. The ARISA results show an effect from the amendment of organochlorines compared to the non-chlorinated controls implying that organohalide respiring bacteria where enriched at those certain conditions.