A strictly anaerobic betaproteobacteriumGeorgfuchsia toluolicagen. nov., sp. nov. degrades aromatic compounds with Fe(III), Mn(IV) or nitrate as an electron acceptor

Abstract

A bacterium (strain G5G6) that grows anaerobically with toluene was isolated from a polluted aquifer (Banisveld, the Netherlands). The bacterium uses Fe(III), Mn(IV) and nitrate as terminal electron acceptors for growth on aromatic compounds. The bacterium does not grow on sugars, lactate or acetate. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain G5G6 belonged to the Betaproteobacteria. Its closest, but only distantly related, cultured relative is Sterolibacterium denitrificans Chol-1S(T) (94.6% similarity of the 16S rRNA genes), a cholesterol-oxidizing, denitrifying bacterium. Strain G5G6 possesses the benzylsuccinate synthase A (bssA) gene encoding the alpha-subunit of Bss, which catalyzes the first step in anaerobic toluene degradation. The deduced BssA amino acid sequence is closely related to those of Azoarcus and Thauera species, which also belong to the Betaproteobacteria. Strain G5G6 is the first toluene-degrading, iron-reducing bacterium that does not belong to the Geobacteraceae within the Deltaproteobacteria. Based on phylogenetic and physiological comparison, strain G5G6 could not be assigned to a described species. Therefore, strain G5G6 (DSMZ 19032(T)=JCM 14632(T)) is a novel taxon of the Betaproteobacteria. We propose the name Georgfuchsia toluolica gen. nov., sp. nov.

Anaerobic utilization of toluene by marine alpha- and gammaproteobacteria reducing nitrate

“…The anaerobic degradation of aromatic hydrocarbons and alkanes with nitrate as terminal electron acceptor has been previously demonstrated and extensively studied in freshwater environments. Almost all the nitrate-reducing strains isolated so far from terrestrial and freshwater environments belong to the class Betaproteobacteria, and more especially to the genera Thauera, Azoarcus and Georgfuchsia (Dolfing et al, 1990;Evans et al, 1991;Fries et al, 1994;Hess et al, 1997;Rabus & Widdel, 1995b;Ehrenreich et al, 2000;Weelink et al, 2009). Two of the few exceptions so far are hydrocarbon-degrading denitrifiers belonging to the class Gammaproteobacteria that have been isolated from river sediment (genus Dechloromonas) (Chakraborty et al, 2005) and ditch sediment (strain HdN1) (Ehrenreich et al, 2000;Zedelius et al, 2011).…”

Sulfuritalea hydrogenivorans gen. nov., sp. nov., a facultative autotroph isolated from a freshwater lake

“…1) and did not belong to any known lineage of sulfur-oxidizing bacteria. The closest relative of the isolate was Georgfuchsia toluolica G5G6 T (94.7 % sequence similarity), a strict anaerobe that degrades aromatic compounds by reducing Fe(III), Mn(IV) or nitrate as electron acceptors (Weelink et al, 2009). It has been reported that G. toluolica cannot utilize carboxylic acids or hydrogen as electron donors.…”

“…Recently, it was demonstrated that toluene can serve as electron donor for Fe(III) reduction by a novel betaproteobacterial isolate, strain G5G6 T (Weelink et al, 2009). This strain is closely related to the dominant phylotype in denitrifying enrichment cultures growing on p-xylene (Rotaru et al, 2010).…”

“…+, Growth; 2, no growth; ND, not determined. Data were compiled from Weelink et al (2009), Fahrbach et al (2006 and Tarlera & Denner (2003). Nitrate was used as an electron acceptor by all strains studied.…”

Niveibacterium umoris gen. nov., sp. nov., isolated from wetland freshwater

“…At present, the family Rhodocyclaceae comprises 19 recognized genera (http://www.bacterio.net/index.html): Azoarcus (ReinholdHurek et al, 1993), Azonexus (Reinhold-Hurek & Hurek, 2000), Azospira, Azovibrio, Dechloromonas (Achenbach et al, 2001), Dechlorosoma, Denitratisoma (Fahrbach et al, 2006), Ferribacterium (Cummings et al, 1999), Georgfuchsia (Weelink et al, 2009), Methyloversatilis (Kalyuzhnaya et al, 2006), Propionibacter (Meijer et al, 1999), Propionivibrio (Tanaka et al, 1990), Quatrionicoccus (Tindall & Euzéby, 2006), Rhodocyclus, Sterolibacterium (Tarlera & Denner, 2003), Sulfuritalea (Kojima & Fukui, 2011), Thauera (Macy et al, 1993), Uliginosibacterium (Weon et al, 2008) and Zoogloea (Crabtree & McCoy, 1967). Members of the family Rhodocyclaceae are Gram-stain-negative rods found in a variety of habitats such as freshwater ponds, sewage sludge, a swine-waste lagoon and contaminated water.…”