Environmental and Intestinal Phylum Firmicutes Bacteria Metabolize the Plant Sugar Sulfoquinovose via a 6-Deoxy-6-sulfofructose Transaldolase Pathway
Benjamin Frommeyer,
Alexander W. Fiedler,
Sebastian R. Oehler,
Buck T. Hanson,
Alexander Loy,
Paolo Franchini,
Dieter Spiteller,
David Schleheck
Affiliations
Benjamin Frommeyer
Department of Biology, University of Konstanz, 78457 Konstanz, Germany; Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, 78457 Konstanz, Germany
Alexander W. Fiedler
Department of Biology, University of Konstanz, 78457 Konstanz, Germany
Sebastian R. Oehler
Department of Biology, University of Konstanz, 78457 Konstanz, Germany
Buck T. Hanson
Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, 1090 Wien, Austria
Alexander Loy
Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, 1090 Wien, Austria
Paolo Franchini
Department of Biology, University of Konstanz, 78457 Konstanz, Germany
Dieter Spiteller
Department of Biology, University of Konstanz, 78457 Konstanz, Germany; Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, 78457 Konstanz, Germany
David Schleheck
Department of Biology, University of Konstanz, 78457 Konstanz, Germany; Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, 78457 Konstanz, Germany; Corresponding author
Summary: Bacterial degradation of the sugar sulfoquinovose (SQ, 6-deoxy-6-sulfoglucose) produced by plants, algae, and cyanobacteria, is an important component of the biogeochemical carbon and sulfur cycles. Here, we reveal a third biochemical pathway for primary SQ degradation in an aerobic Bacillus aryabhattai strain. An isomerase converts SQ to 6-deoxy-6-sulfofructose (SF). A novel transaldolase enzyme cleaves the SF to 3-sulfolactaldehyde (SLA), while the non-sulfonated C3-(glycerone)-moiety is transferred to an acceptor molecule, glyceraldehyde phosphate (GAP), yielding fructose-6-phosphate (F6P). Intestinal anaerobic bacteria such as Enterococcus gilvus, Clostridium symbiosum, and Eubacterium rectale strains also express transaldolase pathway gene clusters during fermentative growth with SQ. The now three known biochemical strategies for SQ catabolism reflect adaptations to the aerobic or anaerobic lifestyle of the different bacteria. The occurrence of these pathways in intestinal (family) Enterobacteriaceae and (phylum) Firmicutes strains further highlights a potential importance of metabolism of green-diet SQ by gut microbial communities to, ultimately, hydrogen sulfide.
