Real-time imaging reveals that lytic polysaccharide monooxygenase promotes cellulase activity by increasing cellulose accessibility
| Autor: | Shi You Ding, Anran Feng, Bingyao Li, Jonathan D. Walton, Steve Smith, Sungjin Park, Bo Song, Cynthia Collings, Xiaoyan Wang, Wei Shen |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
lcsh:Biotechnology Cellulase Management Monitoring Policy and Law Polysaccharide Applied Microbiology and Biotechnology lcsh:Fuel 03 medical and health sciences chemistry.chemical_compound lcsh:TP315-360 lcsh:TP248.13-248.65 LPMO Biomass Cellulose Trichoderma reesei chemistry.chemical_classification biology Renewable Energy Sustainability and the Environment Research Substrate (chemistry) biology.organism_classification Cellulose microfibril Biorefinery Microcrystalline cellulose 030104 developmental biology General Energy chemistry Chemical engineering CBH I biology.protein Microfibril AFM Lignocellulose Biotechnology |
| Zdroj: | Biotechnology for Biofuels, Vol 11, Iss 1, Pp 1-11 (2018) Biotechnology for Biofuels |
| ISSN: | 1754-6834 |
| Popis: | Background The high cost of enzymes is one of the key technical barriers that must be overcome to realize the economical production of biofuels and biomaterials from biomass. Supplementation of enzyme cocktails with lytic polysaccharide monooxygenase (LPMO) can increase the efficiency of these cellulase mixtures for biomass conversion. The previous studies have revealed that LPMOs cleave polysaccharide chains by oxidization of the C1 and/or C4 carbons of the monomeric units. However, how LPMOs enhance enzymatic degradation of lignocellulose is still poorly understood. Results In this study, we combined enzymatic assays and real-time imaging using atomic force microscopy (AFM) to study the molecular interactions of an LPMO [TrAA9A, formerly known as TrCel61A) from Trichoderma reesei] and a cellobiohydrolase I (TlCel7A from T. longibrachiatum) with bacterial microcrystalline cellulose (BMCC) as a substrate. Cellulose conversion by TlCel7A alone was enhanced from 46 to 54% by the addition of TrAA9A. Conversion by a mixture of TlCel7A, endoglucanase, and β-glucosidase was increased from 79 to 87% using pretreated BMCC with TrAA9A for 72 h. AFM imaging demonstrated that individual TrAA9A molecules exhibited intermittent random movement along, across, and penetrating into the ribbon-like microfibril structure of BMCC, which was concomitant with the release of a small amount of oxidized sugars and the splitting of large cellulose ribbons into fibrils with smaller diameters. The dividing effect of the cellulose microfibril occurred more rapidly when TrAA9A and TlCel7A were added together compared to TrAA9A alone; TlCel7A alone caused no separation. Conclusions TrAA9A increases the accessible surface area of BMCC by separating large cellulose ribbons, and thereby enhances cellulose hydrolysis yield. By providing the first direct observation of LPMO action on a cellulosic substrate, this study sheds new light on the mechanisms by which LPMO enhances biomass conversion. Electronic supplementary material The online version of this article (10.1186/s13068-018-1023-1) contains supplementary material, which is available to authorized users. |
| Databáze: | OpenAIRE |
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