title: A physiologically based kinetic model for bacterial sulfide oxidation.
abstract: In the biotechnological process for hydrogen sulfide removal from gas streams, a variety of oxidation products can be formed. Under natron-alkaline conditions, sulfide is oxidized by haloalkaliphilic sulfide oxidizing bacteria via flavocytochrome c oxidoreductase. From previous studies, it was concluded that the oxidation-reduction state of cytochrome c is a direct measure for the bacterial end-product formation. Given this physiological feature, incorporation of the oxidation state of cytochrome c in a mathematical model for the bacterial oxidation kinetics will yield a physiologically based model structure. This paper presents a physiologically based model, describing the dynamic formation of the various end-products in the biodesulfurization process. It consists of three elements: 1) Michaelis-Menten kinetics combined with 2) a cytochrome c driven mechanism describing 3) the rate determining enzymes of the respiratory system of haloalkaliphilic sulfide oxidizing bacteria. The proposed model is successfully validated against independent data obtained from biological respiration tests and bench scale gas-lift reactor experiments. The results demonstrate that the model is a powerful tool to describe product formation for haloalkaliphilic biomass under dynamic conditions. The model predicts a maximum S⁰ formation of about 98 mol%. A future challenge is the optimization of this bioprocess by improving the dissolved oxygen control strategy and reactor design.
authors.affiliation: Sub-department of Environmental Technology, Wageningen University, Bornse Weilanden 9, P.O. Box 17, 6700 AA Wageningen, The Netherlands. johannes.klok@wur.nl
authors.forename: Johannes B M
authors.initials: JB
authors.lastname: Klok
authors.forename: Marco
authors.initials: M
authors.lastname: de Graaff
authors.forename: Pim L F
authors.initials: PL
authors.lastname: van den Bosch
authors.forename: Nadine C
authors.initials: NC
authors.lastname: Boelee
authors.forename: Karel J
authors.initials: KJ
authors.lastname: Keesman
authors.forename: Albert J H
authors.initials: AJ
authors.lastname: Janssen
mesh_terms: D019843:Archaeal Proteins / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology / Q000469:parasitology; D001709:Biotechnology / Q000379:methods*; D045304:Cytochromes c / Q000378:metabolism*; D006862:Hydrogen Sulfide / Q000032:analysis / Q000378:metabolism*; D007700:Kinetics; D008954:Models, Biological; D019633:Natronobacterium / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D058458:Nitrogen Cycle; D010084:Oxidation-Reduction; D011809:Quinones / Q000378:metabolism; D018505:Waste Management / Q000379:methods*
chemical_list: D019843:Archaeal Proteins; D001426:Bacterial Proteins; D011809:Quinones; D045304:Cytochromes c; D006862:Hydrogen Sulfide