Ligninolytic Enzymes Produced by Phanerohaete Chrysosporium 1038 and Biotransformation of Lignin

ABSTRACT

The influence of nitrogen and Mn²⁺ ions concentrations in growth medium on the activity of extracellular lignin degradation enzymes: lignin peroxidase (LiP—EC 1.11.1.14), manganese peroxidase (MnP—EC 1.11.1.13) and laccase (Lac—EC 1.10.3.2), produced by Phanerochaete chrysosporium strain 1038, was studied. Evidence for de lignification processes was provided by FTIR spectroscopy after 24 h incubation of lignin samples with concentrated extracellular fluids of activated strain 1038. FTIR spectra showed decrease of carboxylic groups and increase of hydroxylated and methoxylated aliphatic groups, which indicates an oxidative cleavage. The resulting modifications of the lignin structure are due to the low specificity of the ligninolytic enzyme system, consisting of extracellular LiP, MnP and Lac. The addition of 3.5mg/L Mn²⁺, 63 mg/L Cu²⁺ and 2.5mM veratryl alcohol is necessary for the activation of lignolytic complex and obtaining of optimal conditions for delignification process after incubation of lignin samples with fluids from the strain. The effect of growth conditions on the enzyme activities of Phanerochaete chrysosporium 1038 and efficiency of delignification procedure are discussed.

Keywords:

• laccase
• lignin peroxidase
• manganese peroxidase
• Phanerochaete chrysosporium