Effects of temperature, ultraviolet radiation and pectin methyl esterase on aerobic methane release from plant material

This study examines the effects of different irradiance types on aerobic methane (CH4) efflux rates from terrestrial plant material. Furthermore, the role of the enzyme pectin methyl esterase (PME) on CH4 efflux potential was also examined. Different types of plant tissue and purified pectin were incubated in glass vials with different combinations of irradiation and/or temperature. Purified dry pectin was incubated in solution, and with or without PME. Before and after incubation, the concentration of CH4 was measured with a gas chromatograph. Rates of CH4 emission were found to depend exponentially on temperature and linearly on UV-B irradiance. UV-B had a greater stimulating effect than UV-A, while visible light had no effect on emission rates. PME was found to substantially reduce the potential for aerobic CH4 emissions upon demethylation of pectin.