title: Biofilm formation, communication and interactions of leaching bacteria during colonization of pyrite and sulfur surfaces.
abstract: Bioleaching of metal sulfides is an interfacial process where biofilm formation is considered to be important in the initial steps of this process. Among the factors regulating biofilm formation, molecular cell-to-cell communication such as quorum sensing is involved. A functional LuxIR-type I quorum sensing system is present in Acidithiobacillus ferrooxidans. However, cell-to-cell communication among different species of acidophilic mineral-oxidizing bacteria has not been studied in detail. These aspects were the scope of this study with emphasis on the effects exerted by the external addition of mixtures of synthetic N-acyl-homoserine-lactones on pure and binary cultures. Results revealed that some mixtures had inhibitory effects on pyrite leaching. Some of them correlated with changes in biofilm formation patterns on pyrite coupons. We also provide evidence that A. thiooxidans and Acidiferrobacter spp. produce N-acyl-homoserine-lactones. In addition, the observation that A. thiooxidans cells attached more readily to pyrite pre-colonized by living iron-oxidizing acidophiles than to heat-inactivated or biofilm-free pyrite grains suggests that other interactions also occur. Our experiments show that pre-cultivation conditions influence A. ferrooxidans attachment to pre-colonized pyrite surfaces. The understanding of cell-to-cell communication may consequently be used to develop attempts to influence biomining/bioremediation processes.
authors.affiliation: Universität Duisburg-Essen, Biofilm Centre, Universitätsstraße. 5, 45141 Essen, Germany. Electronic address: soeren.bellenberg@uni-due.de.
authors.forename: Sören
authors.initials: S
authors.lastname: Bellenberg
authors.affiliation: Universidad de Chile, Facultad de Ciencias, Departamento de Biología, Las Palmeras, 3425 Santiago, Chile. Electronic address: maujav2004@hotmail.com.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Díaz
authors.affiliation: Universität Duisburg-Essen, Biofilm Centre, Universitätsstraße. 5, 45141 Essen, Germany. Electronic address: nanninoel@aol.com.
authors.forename: Nanni
authors.initials: N
authors.lastname: Noël
authors.affiliation: Universität Duisburg-Essen, Biofilm Centre, Universitätsstraße. 5, 45141 Essen, Germany. Electronic address: wolfgang.sand@uni-due.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Sand
authors.affiliation: Plant Biochemistry, Ruhr Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany. Electronic address: ansgar.poetsch@rub.de.
authors.forename: Ansgar
authors.initials: A
authors.lastname: Poetsch
authors.affiliation: Universidad de Chile, Facultad de Ciencias, Departamento de Biología, Las Palmeras, 3425 Santiago, Chile. Electronic address: nguilian@uchile.cl.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Guiliani
authors.affiliation: Universität Duisburg-Essen, Biofilm Centre, Universitätsstraße. 5, 45141 Essen, Germany. Electronic address: mario.vera@uni-due.de.
authors.forename: Mario
authors.initials: M
authors.lastname: Vera
mesh_terms: D054742:Acyl-Butyrolactones / Q000378:metabolism; D001419:Bacteria / Q000254:growth & development* / Q000378:metabolism*; D018407:Bacterial Physiological Phenomena; D018441:Biofilms / Q000254:growth & development*; D004783:Environmental Microbiology; D007501:Iron / Q000378:metabolism*; D056265:Microbial Interactions; D013440:Sulfides / Q000378:metabolism*; D013455:Sulfur / Q000378:metabolism*
chemical_list: D054742:Acyl-Butyrolactones; D013440:Sulfides; C011342:pyrite; D013455:Sulfur; D007501:Iron
keywords: Biofilm formation; Bioleaching; N-Acyl-homoserine-lactone; Pyrite; Quorum sensing