Open AccessDissecting the roles of Escherichia coli hydrogenases in biohydrogen production
Author(s) -
Redwood Mark D.,
Mikheenko Iryna P.,
Sargent Frank,
Macaskie Lynne E.
Publication year - 2008
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.1574-6968.2007.00966.x
Subject(s) - hydrogenase , biohydrogen , escherichia coli , fermentation , biochemistry , anaerobic exercise , mixed acid fermentation , fermentative hydrogen production , formate , chemistry , biology , hydrogen production , bacteria , enzyme , gene , lactic acid , catalysis , genetics , lactic acid fermentation , physiology
Escherichia coli can perform at least two modes of anaerobic hydrogen metabolism and expresses at least two types of hydrogenase activity. Respiratory hydrogen oxidation is catalysed by two ‘uptake’ hydrogenase isoenzymes, hydrogenase ‐1 and ‐2 (Hyd‐1 and ‐2), and fermentative hydrogen production is catalysed by Hyd‐3. Harnessing and enhancing the metabolic capability of E. coli to perform anaerobic mixed‐acid fermentation is therefore an attractive approach for bio‐hydrogen production from sugars. In this work, the effects of genetic modification of the genes encoding the uptake hydrogenases, as well as the importance of preculture conditions, on hydrogen production and fermentation balance were examined. In suspensions of resting cells pregrown aerobically with formate, deletions in Hyd‐3 abolished hydrogen production, whereas the deletion of both uptake hydrogenases improved hydrogen production by 37% over the parent strain. Under fermentative conditions, respiratory H 2 uptake activity was absent in strains lacking Hyd‐2. The effect of a deletion in hycA on H 2 production was found to be dependent upon environmental conditions, but H 2 uptake was not significantly affected by this mutation.