Selection and Characterization of Microbial Communities to Improve Swine manure methansiation at Low Temperature

Psychrophilic anaerobic digestion may offer many advantages for livestock farms in temperate climate but it is limited by the long time required for microbial community adaptation to low temperature. The first part of this study focused on selecting a so called psychrophilic inoculum producing methane at 13°C. Among 4 different manure sources, stored swine manure gave the best result with a yield of 42 L CH4/kg VSsubstrate·day after a 9 month period of acclimation. The second part of the study focused on the understanding of archaeal communities’ adaptation of this psychrophilic inoculum to temperature changes (35° - 25°C - 15°C - 5°C). Methane production rates were monitored and coupled with archaeal community analysis to link microbial populations to methane production. The results show that adaptation to low temperature requires archaeal populations’ shifts within the community with species potentially better fitted to lower temperatures.