title: Effects of non-ionic surfactants on the interactions between cellulases and tannic acid: a model system for cellulase-poly-phenol interactions.
abstract: Addition of non-ionic surfactants (NIS) is known to accelerate enzymatic lignocellulose hydrolysis. The mechanism behind this accelerating effect is still not elucidated but has been hypothesized to originate from favorable NIS-lignin interactions which alleviate non-productive adsorption of cellulases to lignin. In the current work we address this hypothesis using tannic acid (TAN) as a general poly-phenolic model compound (for lignin and soluble phenolics) and measure the mutual interactions of cellulases (CBHI, CBHII, EGI, EGII and BG), TAN and NIS (Triton X-100) using isothermal titration calorimetry (ITC). The experimental results suggest rather strong enzyme-specific interactions with TAN in reasonable agreement with enzyme specific lignin inhibition found in the literature. Enzyme-TAN interactions were disrupted by the presence of NIS by a mechanism of strong TAN-NIS interaction. The presence of NIS also alleviated the inhibitory effect of TAN on cellulase activity. All together the current work provides strong indications that favorable NIS-poly-phenol interactions alleviate non-productive cellulase-poly-phenol interactions and hence may provide a mechanism for the accelerating effect of NIS on lignocellulose hydrolysis.
authors: Roskilde University, NSM, Biomaterials, Universitetsvej 1, DK-4000, Roskilde, Denmark.
authors: S N
authors: SN
authors: Olsen
authors: C
authors: C
authors: Bohlin
authors: L
authors: L
authors: Murphy
authors: K
authors: K
authors: Borch
authors: K C
authors: KC
authors: McFarland
authors: M D
authors: MD
authors: Sweeny
authors: P
authors: P
authors: Westh
mesh_terms: D001709:Biotechnology / Q000379:methods; D002152:Calorimetry, Differential Scanning; D044602:Cellulases / Q000378:metabolism; D006868:Hydrolysis; D008031:Lignin / Q000378:metabolism; D008954:Models, Biological; D017830:Octoxynol / Q000494:pharmacology*; D013501:Surface-Active Agents / Q000494:pharmacology*; D013634:Tannins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D013501:Surface-Active Agents; D013634:Tannins; C036909:lignocellulose; D017830:Octoxynol; D008031:Lignin; D044602:Cellulases