Isolation of lignin-degrading strain and its enzyme producing characteristics in corn stover degradation

Abstract:

[Objective] The objective of this study was to screen lignin-degrading fungi and study their lignin-degrading enzyme using corn stover as substrate.[Methods] Lignin-degrading fungi were isolated from decayed corn stover from different latitude and longitude of Jilin Province by using guaiacol and aniline blue culture medium. Strains were identified by morphological screening followed by the phylogenetic analysis of ITS sequences deciphering their taxonomic status. Through the analysis of the activity of extracellular ligninase produced during the solid-state fermentation of corn stover, the most efficient stover-degrading fungi were selected.[Results] A highly efficient corn stover degrading fungus was isolated and named as W2 (Irpex lacteus W2). Manganese peroxidase produced after 4 to 8 days showed an ascending trend, and reached the peak value of 86.31 U/mL at 8 d, which was 88.20% higher than that of Phanerochaete chrysosporium (P<0.01). Laccase activity of this fungus was higher than that of Phanerochaete chrysosporium (45.86 U/mL) and reached 20.60 U/mL at 8 d, which was 40.76% higher than the control (P<0.05).[Conclusion] An efficient corn stover degrading fungus was isolated and identified as Irpex lacteus W2, with high activity of peroxidase and laccase during the degradation process.

Key words:corn stover;ligninase;screening;manganese peroxidase;laccase