Identification of a haloalkaliphilic and thermostable cellulase with improved ionic liquid tolerance

Zhang, Tao, Datta, Supratim, Eichler, Jerry, Ivanova, Natalia, Axen, Seth D., Kerfeld, Cheryl A., Chen, Feng, Kyrpides, Nikos, Hugenholtz, Philip, Cheng, Jan-Fang, Sale, Kenneth L., Simmons, Blake and Rubin, Eddy (2011) Identification of a haloalkaliphilic and thermostable cellulase with improved ionic liquid tolerance. Green Chemistry, 13 8: 2083-2090. doi:10.1039/c1gc15193b

Author Zhang, Tao
Datta, Supratim
Eichler, Jerry
Ivanova, Natalia
Axen, Seth D.
Kerfeld, Cheryl A.
Chen, Feng
Kyrpides, Nikos
Hugenholtz, Philip
Cheng, Jan-Fang
Sale, Kenneth L.
Simmons, Blake
Rubin, Eddy
Title Identification of a haloalkaliphilic and thermostable cellulase with improved ionic liquid tolerance
Journal name Green Chemistry   Check publisher's open access policy
ISSN 1463-9262
Publication date 2011
Sub-type Article (original research)
DOI 10.1039/c1gc15193b
Open Access Status Not Open Access
Volume 13
Issue 8
Start page 2083
End page 2090
Total pages 8
Place of publication Cambridge, U.K.
Publisher Royal Society of Chemistry
Collection year 2012
Language eng
Formatted abstract
Hu-CBH1, a haloalkaliphilic and thermostable cellulase, likely contains negatively charged acidic amino acids on the surface and is resistant to ionic liquids.

Some ionic liquids (ILs) have been shown to be very effective solvents for biomass pretreatment. It is known that some ILs can have a strong inhibitory effect on fungal cellulases, making the digestion of cellulose inefficient in the presence of ILs. The identification of IL-tolerant enzymes that could be produced as a cellulase cocktail would reduce the costs and water use requirements of the IL pretreatment process. Due to their adaptation to high salinity environments, halophilic enzymes are hypothesized to be good candidates for screening and identifying IL-resistant cellulases. Using a genome-based approach, we have identified and characterized a halophilic cellulase (Hu-CBH1) from the halophilic archaeon, Halorhabdus utahensis. Hu-CBH1 is present in a gene cluster containing multiple putative cellulolytic enzymes. Sequence and theoretical structure analysis indicate that Hu-CBH1 is highly enriched with negatively charged acidic amino acids on the surface, which may form a solvation shell that may stabilize the enzyme, through interaction with salt ions and/or water molecules. Hu-CBH1 is a heat tolerant haloalkaliphilic cellulase and is active in salt concentrations up to 5 M NaCl. In high salt buffer, Hu-CBH1 can tolerate alkali (pH 11.5) conditions and, more importantly, is tolerant to high levels (20% w/w) of ILs, including 1-allyl-3-methylimidazolium chloride ([Amim]Cl). Interestingly, the tolerances to heat, alkali and ILs are found to be salt-dependent, suggesting that the enzyme is stabilized by the presence of salt. Our results indicate that halophilic enzymes are good candidates for the screening of IL-tolerant cellulolytic enzymes.
Keyword Halophilic malate-dehydrogenase
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2012 Collection
School of Chemistry and Molecular Biosciences
Institute for Molecular Bioscience - Publications
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