Short-Term Exposure to Thermophilic Temperatures Facilitates CO Uptake by Thermophiles Maintained under Predominantly Mesophilic Conditions

Document Type


Publication Date



Three phylogenetically and phenotypically distinct CO-oxidizing thermophiles (  CPP55 (Firmicutes),   PS4 (Deinococcus-Thermus) and   PM5 (Chloroflexi)) and one CO-oxidizing mesophile ( WA (Betaproteobacteria)) isolated from volcanic soils were used to assess growth responses and CO uptake rates during incubations with constant temperatures (25 °C and 55 °C) and during multi-day incubations with a temperature regime that cycled between 20 °C and 55 °C on a diurnal basis (alternating mesophilic and thermophilic temperatures, AMTT). The results were used to test a conjecture that some thermophiles can survive in mesothermal habitats that experience occasional thermophilic temperatures.   PS4, which does not form spores, was able to grow and oxidize CO under all conditions, while the spore-forming   CPP55 grew and oxidized CO during the AMTT regime and at 55 °C, but was not active at 25 °C.   PM5, also a spore former, only grew at 55 °C but oxidized CO during AMTT and 55 °C incubations. In contrast, the non-sporing mesophile, WA, was only able to grow and oxidize CO at 25 °C; growth and CO uptake ceased during the AMTT incubations after exposure to the initial round of thermophilic temperatures. Collectively, these results suggest that temporary, periodic exposure to permissive growth temperatures could help maintain populations of thermophiles in mesothermal habitats after deposition from the atmosphere or other sources.

Publication Source (Journal or Book title)


This document is currently not available here.