Laccase SilA from Streptomyces ipomoeae CECT 3341, a key enzyme for the degradation of lignin from agricultural residues?

PLoS One. 2017 Nov 7;12(11):e0187649. doi: 10.1371/journal.pone.0187649. eCollection 2017.

Abstract

The role of laccase SilA produced by Streptomyces ipomoeae CECT 3341 in lignocellulose degradation was investigated. A comparison of the properties and activities of a laccase-negative mutant strain (SilA-) with that of the wild-type was studied in terms of their ability to degrade lignin from grass lignocellulose. The yields of solubilized lignin (acid precipitable polymeric lignin, APPL) obtained from wheat straw by both strains in Solid State Fermentation (SSF) conditions demonstrated the importance of SilA laccase in lignin degradation with the wild-type showing 5-fold more APPL produced compared with the mutant strain (SilA-). Analytical pyrolysis and FT-IR (Fourier Transform Infrared Spectroscopy) confirmed that the APPL obtained from the substrate fermented by wild-type strain was dominated by lignin derived methoxyphenols whereas those from SilA- and control APPLs were composed mainly of polysaccharides. This is the first report highlighting the role of this laccase in lignin degradation.

MeSH terms

  • Agriculture*
  • Fermentation
  • Genes, Bacterial
  • Hydrolysis
  • Laccase / isolation & purification*
  • Laccase / metabolism
  • Lignin / metabolism*
  • Mutation
  • Spectroscopy, Fourier Transform Infrared
  • Streptomyces / enzymology*
  • Streptomyces / genetics
  • Triticum / metabolism

Substances

  • Lignin
  • Laccase

Grants and funding

This study was funded in part by projects CTQ2014-56038-C3-2-R and CGL2016-78937-R (INTERCARBON) from the Spanish Ministry for Economy and Competitiveness. N.T Jiménez-Morillo acknowledges a FPI research grant (BES-2013-062573) and A.Blánquez is awarded with a grant from the project CTQ2014-56038-C3-2-R.