CHARACTERIZATION OF THE CELLULOSE-DEGRADING BACTERIUM NCIMB-10462

The gram-negative cellulase-producing bacterium NCIMB 10462 has been p reviously named Pseudomonas fluorescens subsp. or var. cellulosa. Beca use of renewed interest in cellulose-degrading bacteria for use in the bioconversion of cellulose to chemical feed stocks and fuels, we re-e xamined the characteristics of this microorganism to determine its tru e metabolic potential. Metabolic and physical characterization of NCIM B 10462 revealed that this is an alkalophilic, nonfermentative, gram-n egative, oxidase-positive, motile, cellulose-degrading bacterium. The aerobic substrate utilization profile of this bacterium has few charac teristics consistent with a classification of P. fluorescens and a ver y low probability match with the genus Sphingomonas. However, total li pid analysis did not reveal that any sphingolipid bases are produced b y this bacterium. NCIMB 10462 grows best aerobically, but also grows w ell in complex media under reducing conditions. NCIMB 10462 grows slow ly under anaerobic conditions on complex media, but growth on cellulos ic media occurred only under aerobic conditions. Total fatty acid anal ysis (MIDI) of NCIMB 10462 failed to group this bacterium with a known pseudomonas species. However, fatty acid analysis of the bacteria whe n grown at temperatures below 37 degrees C suggest that the organism i s a pseudomonad. Since a predominant characteristic of this bacterium is its ability to degrade cellulose, we suggest that it be called Pseu domonas cellulosa.