Fig. 7: Transformation of lignin by LacOST51.
A Reactivity of LacOST51with β-O-4 biaryl ethers. LacOST51 (1 μM) was incubated for 6 h with 1 mM guaiacylglycerol-β-guaiacyl ether (left) or veratrylglycerol-β-guaiacyl ether (right) with 20 mM sodium phosphate and pH 8 at 55 °C. HPLC traces are of reactions with (solid line) and without (dotted) enzyme. B Treatment of EMAL with LacOST51. LacOST51 (6 μM) was incubated for 6 days with 0.5% (w/v) EMAL (12.5 mM sodium phosphate, pH 8, 10% DMSO, at 30 °C). HPLC traces are of reactions with (solid line) and without (dotted) enzyme. The identities of the indicated compounds were confirmed using authentic standards. DMBQ: 2,6-Dimethoxy benzoquinone. Inset: Effect of laccase treatment on molar mass distribution of Eucalyptus EMAL, where EMAL was treated with either LacOST51, sLac or no enzyme (bsLac treatment generated insoluble material that was not analyzed using GPC). C HSQC NMR spectra of laccase-treated EMAL. EMAL was incubated with no enzyme (a) and (d), LacOST51 (b) and (e), or sLac (c) and (f). The top and the bottom panels show the aliphatic and aromatic regions, respectively, of the 2D-NMR spectra. Linkages and units are expressed as per 100 aromatic units (100 Ar), which represented the integration of the G2 + 1/2S2. Structures of the regions are shown to the right.
