Open AccessHeterotrophic sulfur reduction by Thermotoga sp. strain FjSS3.B1
Author(s) -
Janssen Peter H.,
Morgan Hugh W.
Publication year - 1992
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1992.tb05419.x
Subject(s) - sulfur , sulfide , chemistry , redox , hydrogen sulfide , yield (engineering) , heterotroph , fermentation , inorganic chemistry , hydrogen , biochemistry , materials science , bacteria , organic chemistry , biology , metallurgy , genetics
Thermotoga sp. strain FjSS3.B1 was able to reduce sulfur to sulfide when grown on a mineral medium with glucose as the sole carbon and energy source. There was no increase in specific growth yield coupled to sulfur reduction, but the specific growth rate, final growth yield, and tolerance of H 2 were all increased in the presence of sulfur. At dissolved H 2 concentrations, of 550 to 600 μmol/1 (at 77°C) growth was not possible unless sulfur was added. Glucose was fermented via the Embden‐Meyerhof‐Parnas pathway to lactate, acetate, H 2 and CO 2 (and other unidentified minor products). The thermodynamic problems associated with the relatively high redox potential electrons from the 1,3‐bisphosphoglycerate/glyceraldehyde 3‐phosphate couple ( E ′ 0 =− 350 mV) are overcome by reducing sulfur to sulfide ( E ′ 0 =− 270 mV) rather than the energetically unfavourable production of H 2 ( E ′ 0 =− 414 mV). Under high hydrogen partial pressures there was increased production of lactate as an alternative electron sink. The results indicate that sulfur reduction operates primarily as an electron sink rather than as a detoxification reaction or energy‐generating mechanism.