Primary structure of the carbohydrate-binding modules in various cellulolytic, thermophilic, anaerobic, ethanol-producing isolates

Abstract

In the present study, the carbohydrate-binding module (CBM) coding sequences of the cellulosomes of 13 thermophilic, cellulolytic, anaerobic, ethanol-producing bacterial isolates having some variations in their growth and cellulose degradation capacities were amplified by PCR and then sequenced. The sequence analysis of the amplicons revealed that CBMs of 7 of the isolates including the isolate 7-9-1 with the highest capacity of cellulose degradation in solid medium have 100% identity in both nucleotide and amino acid sequences to CipB of Clostridium thermocellum in the compared regions. On the other hand, CBM of the isolate 7-1-2, also having a high cellulolytic activity, was found to differ for as much as 66 amino acid residues out of 100 (66%). The isolate 7-9-4 with a relatively low cellulose-degrading capacity also displayed amino acid variation for this protein, but only for 4 out of 118 residues. © TÜBİTAK. © 2008 Elsevier B.V., All rights reserved.