Respirometry methods for assessing microbial activity of thermophilic bioleaching Archaea

摘要

Respirometery methods have been used for many years to assess the microbial activity of mainly heterotrophic bacteria. Using this technique, the consumption of oxygen and evolution of carbon dioxide, for heterotrophic carbon catabolism, can be used to assess microbial activity. In the case of autotrophic bioleaching bacteria carbon dioxide is used as a carbon source resulting in the consumption of both oxygen and carbon dioxide. The use of such respirometry techniques at high temperatures (up to 80℃) for the investigation of bioleaching Archaea, however, poses particular difficulties. At these elevated temperatures, the solubility of oxygen into the liquid phase is particularly poor. This work details specific methods by which high temperature constraints are overcome while monitoring the activity of thermophilic Archaea using a Micro-Oxymax respirometer (Columbus Instruments). The use of elevated headspace oxygen concentrations, in order to overcome low oxygen solubility, is demonstrated as well as the effect of such elevated oxygen concentrations on microbial oxygen consumption rates. In addition, this paper details methods by which respirometry data can be used to quantify inhibitory effects of potentially toxic compounds.