title: The enrichment of an alkaliphilic biofilm consortia capable of the anaerobic degradation of isosaccharinic acid from cellulosic materials incubated within an anthropogenic, hyperalkaline environment.
abstract: Anthropogenic hyperalkaline sites provide an environment that is analogous to proposed cementitious geological disposal facilities (GDF) for radioactive waste. Under anoxic, alkaline conditions cellulosic wastes will hydrolyze to a range of cellulose degradation products (CDP) dominated by isosaccharinic acids (ISA). In order to investigate the potential for microbial activity in a cementitious GDF, cellulose samples were incubated in the alkaline (∼pH 12), anaerobic zone of a lime kiln waste site. Following retrieval, these samples had undergone partial alkaline hydrolysis and were colonized by a Clostridia-dominated biofilm community, where hydrogenotrophic, alkaliphilic methanogens were also present. When these samples were used to establish an alkaline CDP fed microcosm, the community shifted away from Clostridia, methanogens became undetectable and a flocculate community dominated by Alishewanella sp. established. These flocs were composed of bacteria embedded in polysaccharides and proteins stabilized by extracellular DNA. This community was able to degrade all forms of ISA with >60% of the carbon flow being channelled into extracellular polymeric substance (EPS) production. This study demonstrated that alkaliphilic microbial communities can degrade the CDP associated with some radioactive waste disposal concepts at pH 11. These communities divert significant amounts of degradable carbon to EPS formation, suggesting that EPS has a central role in the protection of these communities from hyperalkaline conditions.
authors.affiliation: Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK.
authors.forename: C J
authors.initials: CJ
authors.lastname: Charles
authors.affiliation: Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK.
authors.forename: S P
authors.initials: SP
authors.lastname: Rout
authors.affiliation: Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK.
authors.forename: E J
authors.initials: EJ
authors.lastname: Garratt
authors.affiliation: Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK.
authors.forename: K
authors.initials: K
authors.lastname: Patel
authors.affiliation: Department of Chemical Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK.
authors.forename: A P
authors.initials: AP
authors.lastname: Laws
authors.affiliation: Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK p.n.humphreys@hud.ac.uk.
authors.forename: P N
authors.initials: PN
authors.lastname: Humphreys
mesh_terms: D034241:Alteromonadaceae / Q000235:genetics / Q000378:metabolism*; D000693:Anaerobiosis / Q000502:physiology; D001105:Archaea / Q000378:metabolism*; D018441:Biofilms; D002482:Cellulose / Q000378:metabolism*; D003013:Clostridium / Q000235:genetics / Q000378:metabolism*; D004777:Environment; D059013:Microbial Consortia; D008969:Molecular Sequence Data; D011850:Radioactive Waste; D012037:Refuse Disposal; D013400:Sugar Acids / Q000378:metabolism*
chemical_list: D011850:Radioactive Waste; D013400:Sugar Acids; C492894:isosaccharinic acid; D002482:Cellulose
keywords: Biofilm; EPS; ISA; Isosaccharinic acid; hyperalkaline