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

A new peptid-degrading, strictly anaerobic bacterium, designated strain TMC4T, was isolated from an olive mill wastewater treatment digester. Cells of strain TMC4T were motile, rod-shaped (5-10 x 0.6-1.2 microns), stained Gram-positive and formed terminal to subterminal spores that distended the cells. Optimal growth occurred at 37°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 acid or alcohols. The end-products of degradation were : aceatate and butyrate from lysine and crotonate ; acetate, butyrate, H2 and CO2 from Biotrypcase, gelatin and peptone ; acetate, alanine, H2 and CO2 from cysteine ; acetate, H2 and CO2 from serine, cysteine and yeast extract ; acetate and formate from histidine ; propionate from methionine ; methyl 2-butyrate, H2 and CO2 from isoleucine ; acetate and ethanol from arginine ; and acetate, propionate, butyrate, methyl 2-butyrate, H2 and CO2 from Casamino acids. The DNA G+C content of strain TMC4T was 31 mol%. Phylogeny based on 16S rRNA sequence analysis showed that strain TMC4T 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 TMC4T and those of its nearest relative, strain TMC4T is proposed as a new species of the genus #Clostridium$, #Clostridium peptidivorans$ sp. nov. Strain TMC4T has been deposited in the DSMZ as strain DSM 12505T. (Résumé d'auteur