PT  - JOURNAL ARTICLE
AU  - Nikita A. Khlystov
AU  - Yasuo Yoshikuni
AU  - Samuel Deutsch
AU  - Elizabeth S. Sattely
TI  - A plant host enables the heterologous production and combinatorial study of fungal lignin-degrading enzymes
AID  - 10.1101/794834
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 794834
4099  - http://biorxiv.org/content/early/2019/10/07/794834.short
4100  - http://biorxiv.org/content/early/2019/10/07/794834.full
AB  - Lignin has significant potential as an abundant and renewable source for commodity chemicals yet remains vastly underutilized. Efforts towards engineering a biochemical route to the valorization of lignin are currently limited by the lack of a suitable heterologous host for the production of lignin-degrading enzymes. Here, we show that expression of fungal genes in Nicotiana benthamiana enables production of members from seven major classes of enzymes associated with lignin degradation (23 of 35 tested) in soluble form for direct use in lignin activity assays. We combinatorially characterized a subset of these enzymes in the context of model lignin dimer oxidation, revealing that fine-tuned coupling of peroxide-generators to peroxidases results in more extensive C-C bond cleavage compared to direct addition of peroxide. Comparison of peroxidase isoform activity revealed that the extent of C-C bond cleavage depends on peroxidase identity, suggesting that peroxidases are individually specialized in the context of lignin oxidation. We anticipate the use of N. benthamiana as a platform to rapidly produce a diverse array of fungal lignin-degrading enzymes will facilitate a better understanding of their concerted role in nature and unlock their potential for lignin valorization, including within the plant host itself.