Isolation and identification of cellulolytic bacteria involved in the degradation of natural cellulosic fibres

In search for bacterial cultures that are able to rapidly degrade cellulosi c plant fibres in vitro, 77 cellulolytic strains were isolated from Belgian and Czech soils after enrichment on flax or sisal fibres as sole sources o f carbon. The strains were characterized using fatty acid analysis, and 74 strains were grouped into three major clusters by numerical analysis. The f irst major cluster contained Cellulomonas strains. Within this cluster thre e subclusters could be delineated by principal component analysis, that wer e recognized by their fatty acid compositions as Cellulomonas gelida, Cellu lomonas biazotea and Cellulomonas cellulans, containing 9, 8 and 13 strains respectively The second major cluster, with 9 strains, was assigned to Fla vobacterium johnsoniae. The 34 strains of the third cluster could not be id entified by commercial identification systems on the basis of their fatty a cid profiles and API ZONE profiles. On the basis of their phenotypic charac teristics they met the description of the genus Cellvibrio, their fatty aci d profiles were similar to those of four authentic Cellvibrio mixtus strain s, and the 16S rRNA genes frolic four representatives showed up to 97.8% se quence similarity to 16S rDNA from Cellvibrio mixtus ACM 2603. Three non-cl ustered strains were assigned to Curtobacterium flaccumfaciens, Achromobact er piechaudii and Pseudomonas mendocina. Two strains assigned to Cellvibrio were able to degrade several flax, broom and cotton fibres very rapidly in a standardized in vitro rest, causing mass losses of 40 to 86% within 13 d ays of incubation, but not jute.