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Title: Comparative analysis of the ability of Clostridium clariflavum strains and Clostridium thermocellumto utilize hemicellulose and unpretreated plant material

Among themophilic consolidated bioprocessing (CBP) candidate organisms, environmental isolates of Clostridium clariflavum have demonstrated the ability to grow on xylan, and the genome of C. clariflavum DSM 19732 has revealed a number of mechanisms that foster solubilization of hemicellulose that are distinctive relative to the model cellulolytic thermophile Clostridium thermocellum. Growth experiments on xylan, xylooligosaccharides, and xylose reveal that C. clariflavum strains are able to completely break down xylan to xylose and that the environmental strain C. clariflavum sp. 4-2a is able to grow on monomeric xylose. C. clariflavum strains were able to utilize a larger proportion of unpretreated switchgrass, and solubilize a higher proportion of glucan, xylan, and arabinan, with strain 4-2a reaching the highest extent of solubilization of these components (64.7 to 69.4%) compared to C. thermocellum (29.5 to 42.5%). In addition, glycome immunoanalyses of residual plant biomass reveal differences in the extent of degradation of easily accessible xylans, with C. clariflavum strains having increased solubilization of this fraction of xylans relative to C. thermocellum. In conclusion, C. clariflavum strains exhibit higher activity than C. thermocellum in the breakdown of hemicellulose and are capable of degrading xylan to xylooligomers and xylose. This capability seems to also play amore » role in the higher levels of utilization of unpretreated plant material.« less
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [3]
  1. Dartmouth College, Hanover, NH (United States). Thayer School of Engineering; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). BioEnergy Science Center (BESC); Hofstra Univ., Hempstead, NY (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). BioEnergy Science Center (BESC); Univ. of Georgia, Athens, GA (United States)
  3. Dartmouth College, Hanover, NH (United States). Thayer School of Engineering; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). BioEnergy Science Center (BESC)
Publication Date:
OSTI Identifier:
1259857
Type:
Accepted Manuscript
Journal Name:
Biotechnology for Biofuels
Additional Journal Information:
Journal Volume: 7; Journal Issue: 1; Journal ID: ISSN 1754-6834
Publisher:
BioMed Central
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES CBP; Clostridium thermocellum; Clostridium clariflavum; Hemicellulose; Switchgrass