Fig 1.
A; pOJ260-Sipo600 construction (A-1), scheme showing the insertion of the pOJ260-Sipo600 construction in the S. ipomoeae genome by simple crossover (A-2) and photograph showing the production of laccase activity in ABTS-solid media by the wild-type strain (SilA) and the absence of laccase activity in the mutant strain SilA− (A-3). B; Production by PCR of the Sipo1000 fragment and insertion into the pEM4T plasmid between BamHI and EcoRI restriction sites. (B-1), laccase activity determined from S. ipomoeae wild-type, mutant SilA−, recovered mutant (SilA− + pEM4T-sipo1000) and over-expressed wild-type (B-2).
Fig 2.
Total production of APPL and lignin:carbohydrate ratio obtained from wheat straw fermented with S. ipomoeae wild-type and mutant strains and from an un-inoculated wheat straw.
Fig 3.
(A) Py-GC/MS chromatograms of APPL obtained from control and wheat straw transformed in SSF conditions by wild-type (SilA) and laccase-negative mutant (SilA−) strains; the main domains where the different precursors are eluted are indicated. (B) Average Py-EI-MS spectra corresponding to the domains where pyrolysis polysaccharides (cellulose) and lignin derived compounds elute (min 2 to min 14 of the chromatograms).
Fig 4.
FT-IR spectra of APPL obtained from control wheat straw and transformed in SSF conditions by wild-type (SilA) and laccase-negative mutant (SilA−) strains.
Labels on the peaks corresponds to wavenumber of peaks in cm-1 followed by assignation as ester; amide I (Am I); amide II (Am II); lignin and polyphenols (Lg); polysaccharides (Ps).