A psychrotolerant Clostridium species was isolated from vacuum-packed, temperature-abused raw lamb. Colonies of this micro-organism on sheep-blood agar were circular with an entire margin, grey-white, translucent and beta-haemolytic. Cells were single, tapered, motile rods. Elliptical subterminal spores were produced in the late stationary growth phase. Spores did not cause swelling of the maternal cells. The micro-organism was obligately anaerobic. In peptone yeast extract glucose starch (PYGS) broth at pH 7.0, the micro-organism grew optimally between 25.5 and 30.0 degrees C. The temperature range for growth was 2.5-32.2 degrees C. At 26 degrees C, the micro-organism grew optimally at pH 6.8 to 7.0. The pH range for anaerobic growth was 4.7-9.1. The micro-organism was saccharoclastic, hydrolysed starch and degraded xylan. The fermentation products formed in PYGS broth were acetate, formate, lactate, ethanol, butyrate, butanol, hydrogen and carbon dioxide. The G + C content of the DNA was 38.4 mol%. Phylogenetic analyses indicated that the strain belongs to cluster XIVa of the genus Clostridium (sensu Collins et al. 1994). The new strain differed from phylogenetically related clostridia in terms of cellular fatty acid composition, soluble protein profiles and phenotypic properties. On the basis of phenotypic and genotypic characterization data, the strain was assigned to a new species, namely Clostridium algidixylanolyticum. The type strain is strain SPL73T (= DSM 12273T).