Lignin biodegradation with fungi, bacteria and enzymes for producing chemicals and increasing process efficiency

In nature, microorganisms such as fungi or bacteria naturally degrade lignin, inspiring numerous attempts worldwide to investigate these reactions with bio-mimicking methods. The present chapter offers a critical overview of the latest concepts and achievements in lignin biological degradation, focussing on fungi, bacteria and enzymes as catalysts to produce chemicals and their use for novel applications. White-rot fungi Pleurotus ostreatus has been widely investigated due to its high delignification performances, however other strains such as Phanerochaete sp. and Phlebia sp. have proven to have similar potential. Due to their amenability to genetic modification, bacteria have opened the coveted path to chemical production from lignin. Vanillin, ferulic acid or muconate can already be obtained by genetically modified Pseudomonas putida or Rhodococcus jostii. Lignolytic enzymes, e.g. peroxidases or laccases, are yet to find viable applications. Mechanisms of lignin biodegradation and bonds cleavage are being better understood thanks to the study of these elemental reactions.