A Novel Cellulolytic, Anaerobic, and Thermophilic Bacterium,Moorellasp. Strain F21

Abstract

A cellulolytic and thermophilic anaerobe was isolated from soil. This bacterium made a halo on a roll-tube culture containing Avicel. Analysis of the PCR-based 16S rRNA gene sequence showed that the bacterium was closely related to Moorella thermoacetica. Scanning electron microscopy showed the bacterium is a rod and has no protuberant structure on the surface of cells growing on cellulose, suggesting that this strain is a non-cellulosomal cellulolytic bacterium. Carboxymethyl cellulase and xylanase activities were detected in the culture broth. A major fermentation product from ball-milled cellulose was acetate. This strain has a potential to convert cellulosic biomass to acetate, directly.

Acetogenesis in the Energy-Starved Deep Biosphere – A Paradox?

“…Further widely used growth substrates include carbohydrates, other short-chain fatty acids and alcohols, methoxylated aliphatic compounds, betaines, amino acids, and aldehydes (Drake et al, 2006). Even complex organic polymers, such as cellulose or carboxymethylcellulose, are used by some strains (Wolin and Miller, 1994; Karita et al, 2003; Wolin et al, 2003). Due to the limited number of energy substrates on which growth is typically tested, substrate ranges of acetogens may significantly exceed the currently known spectrum.…”

The metagenome of a biogas-producing microbial community of a production-scale biogas plant fermenter analysed by the 454-pyrosequencing technology

“…3 are also known to possess cellulolytic activity. These are for example Moorella thermoacetica (Karita et al, 2003), Clostridium cellulolyticum (Gaudin et al, 2000), Caldicellulosiruptor saccharolyticus (Bagi et al, 2007) and Clostridium phytofermentans (Warnick et al, 2002). Very recently, it could be shown that inoculation of cattle manure with bacteria of the genus Caldicellusiruptor resulted in an increase of the specific methane yield (Nielsen et al, 2007).…”

Physiology of the thermophilic acetogen Moorella thermoacetica

“…a All are growth--supportive, acetogenic substrates except for ethanol, n--propanol, and n--butanol which require thiosulfate, dimethylsulfoxide, or nitrate as an electron acceptor [7,42]. Cellulose has recently been described as a substrate for an organism that is phylogenically closely related to M. thermoacetica [56]. b Nitrite can serve an electron acceptor during glyoxylate--dependent growth [109].…”

“…However, very few efforts to isolate polymerdegrading acetogens have been reported in the literature. It is therefore of particular note that the recent isolation of what appears to be a cellulose--degrading strain of M. thermoacetica [56] suggests that some strains of this acetogen may have the ability to hydrolyze and use complex polymers. "Bryantella formatexigens" (quotation marks indicate that this name has not yet been validated), an acetogen recently isolated from human feces, used amorphous cellulose for growth when first isolated but lost this capability after prolonged cultivation [126].…”