Screening of a fungus capable of powerful and selective delignification on wheat straw

Abstract

To screen and characterize a novel fungus with powerful and selective delignification capability on wheat straw. A fungus capable of efficient delignification under solid-state fermentation (SSF) conditions on wheat straw was screened. After 5 days of incubation, 13.07% of the lignin was removed by fungal degradation, and 7.62% of the holocellulose was lost. Furthermore, 46.53% of the alkali lignin was removed after 2 days of liquid fermentation. The fungus was identified as Fusarium concolor based on its morphology and an analysis of its 18S rDNA gene sequence. The molecular weight distribution of lignin was evaluated by gel permeation chromatography. Enzyme assay indicated that the fungus produced laccase, cellobiose dehydrogenase, xylanase and cellulase during the incubation period. Intracellular lignin peroxidase, manganese peroxidase and laccase were produced during liquid fermentation. We have successfully screened a fungus, F. concolor, which can efficiently degrade the lignin of wheat straw, with slight damage to the cellulose, after 5 days of SSF. The newly isolated strain could be used in pretreatment of lignocellulose materials prior to biopulping, bioconversion into fuel and substrates for the chemical industry.