Clostridium peptidivorans sp nov., a peptide-fermenting bacterium from an olive mill wastewater treatment digester

A new peptide-degrading, strictly anaerobic bacterium, designated strain TMC4(T), was isolated from an olive mill wastewater treatment digester. Cells of strain TMC4(T) were motile, rod-shaped (5-10 x 0.6-1.2 mu m), stained Gram-positive and formed terminal to subterminal spores that distended the cells. Optimal growth occurred at 37 degrees C and pH 7 in an anaerobic basal medium containing 0.5% Casamino acids. Arginine, lysine, cysteine, methionine, histidine, serine, isoleucine, yeast extract, peptone, Biotrypcase, gelatin and crotonate also supported growth, but not carbohydrates, organic acids or alcohols. The endproducts of degradation were: acetate and butyrate from lysine and crotonate; acetate, butyrate, H-2 and CO2 from Biotrypcase, gelatin and peptone; acetate, alanine, H-2 and CO2 from cysteine; acetate, H-2 and CO2 from serine, cysteine and yeast extract; acetate end formate from histidine; propionate from methionine; methyl 2-butyrate, H-2 and CO2 from isoleucine; acetate and ethanol from arginine; and acetate, propionate, butyrate, methyl 2-butyrate, H-2 and CO2 from Casamino acids. The DNA G+C content of strain TMC2(T) was 31 mol%. Phylogeny based on 16S rRNA sequence analysis showed that strain TMC4(T) was a member of the low-G+C-content Gram-positive genus Clostridium, with the closest relative being Clostridium pascui (sequence similarity of 96 %). Due to considerable differences in genomic and phenotypic properties between strain TMC4(T) and those of its nearest relative, strain TMC4(T) is proposed as ii new species of the genus Clostridium, Clostridium peptidivorans sp. nov. Strain TMC4(T) has been deposited in the DSMZ as strain DSM 12505(T).