Characterizing uptake of lignin breakdown products into P. chrysosporium

Valorization of lignin has the potential to significantly improve the economics of lignocellulosic biorefineries.  However, efficient conversion of lignin to useful molecular building blocks has been elusive. Microbial conversion of lignin in nature is efficient, but occurs very slowly.  Engineering microbes to produce more efficient and more directed lignin conversion is a promising strategy. One aspect of that engineering effort is to optimize transport.  However, very little is currently known about lignin transport into microbes.  Indirect evidence such as growth and toxicity studies suggests lignolytic organisms may transport a wide range of mono-, di-, and possibly even higher molecular weight lignin breakdown products across the cellular membrane, but direct measurements of the substrate range and specificity are lacking except for a few select studies.  To that end we are characterizing the profile of lignin-like substrates internalized by P. chrysosporium using mass spectrometry.  We describe the method and report initial results for a range of mono- and di-aryl compounds.