title: [Anaerobic reduction of humus/Fe (III) and electron transport mechanism of Fontibacter sp. SgZ-2].
abstract: Humus and Fe(III) respiration are important extracellular respiration metabolism. Electron transport pathway is the key issue of extracellular respiration. To understand the electron transport properties and the environmental behavior of a novel Fe(III)- reducing bacterium, Fontibacter sp. SgZ-2, capacities of anaerobic humus/Fe(III) reduction and electron transport mechanisms with four electron acceptors were investigated in this study. The results of anaerobic batch experiments indicated that strain SgZ-2 had the ability to reduce humus analog [ 9,10-anthraquinone-2,6-disulfonic acid (AQDS) and 9,10-anthraquinone-2-sulfonic acid (AQS)], humic acids (HA), soluble Fe(III) (Fe-EDTA and Fe-citrate) and Fe(III) oxides [hydrous ferric oxide (HFO)]. Fermentative sugars (glucose and sucrose) were the most effective electron donors in the humus/Fe(III) reduction by strain SgZ-2. Additionally, differences of electron carrier participating in the process of electron transport with different electron acceptors (i. e. , oxygen, AQS, Fe-EDTA and HFO) were investigated using respiratory inhibitors. The results suggested that similar respiratory chain components were involved in the reducing process of oxygen and Fe-EDTA, including dehydrogenase, quinones and cytochromes b-c. In comparison, only dehydrogenase was found to participate in the reduction of AQS and HFO. In conclusion, different electron transport pathways may be employed by strain SgZ-2 between insoluble and soluble electron acceptors or among soluble electron acceptors. Preliminary models of electron transport pathway with four electron acceptors were proposed for strain SgZ-2, and the study of electron transport mechanism was explored to the genus Fontibacter. All the results from this study are expected to help understand the electron transport properties and the environmental behavior of the genus Fontibacter.
authors.forename: Chen
authors.initials: C
authors.lastname: Ma
authors.forename: Gui-qin
authors.initials: GQ
authors.lastname: Yang
authors.forename: Qin
authors.initials: Q
authors.lastname: Lu
authors.forename: Shun-gui
authors.initials: SG
authors.lastname: Zhou
mesh_terms: D000693:Anaerobiosis; D000880:Anthraquinones / Q000737:chemistry; D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D004579:Electron Transport; D005290:Ferric Compounds / Q000737:chemistry*; D006812:Humic Substances / Q000382:microbiology*; D010084:Oxidation-Reduction
chemical_list: D000880:Anthraquinones; D005290:Ferric Compounds; D006812:Humic Substances; C021024:ferric hydroxide; C023554:anthraquinone sulfonate