What is microbial bioenergetics? The application of thermodynamics to quantitatively describe energy production and transformation in microbes. ∆G catabolism ∆G growth { { { e - µ ATP electron donor (ED) ED ox electron acceptor (EA) EAred ∆G maintenance Energy production vs. consumption The Gibbs energy of catabolism gained from fermentation or respiration (e.g., denitrification) is used for growth and maintenance. = + X - - % AC + / - Research and Applications ∆G met = ? ∆G main = ? ∆G cat= = ? ∆G growth = ? F i e l d T h e o r y D e v e l o p m e n t M o d e l i n g L a b o r a t o r y Y = ? CH 4 acetate time concentration d CH 4 dt d acetate dt d biomass dt biomass Heat + ∆S Apply fundamental thermodynamic principles to describe the bio- chemical processes driving both growth and non-growth in micro-organisms. Bioenergetics- informed models explicitly account for energy and microbial growth to predict rates. Range in complexity from black box models to genome- informed models. d CH 4 dt d CO 2 dt d CO 2 dt d CH 4 dt Examine the impact of energy on a process (e.g., waste- water treatment). Typically includes batch, chemostat, and soil columns. Calorimetry may be used to quantify the heats of reaction. Bioenergetics is used combined with transport, geo- chemical, and microbiological data to predict biogeo- chemical rates. For example, the rate of methane production. UWaterloo Microbial Bioenergetics Workshop, July 2018, Christina Smeaton