Towards understanding enzymatic diversity in biological lignin degradation
EMSL Project ID
48411
Abstract
Lignin is an alkyl-aromatic polymer comprising 15-30% of plant cell walls. It is underutilized in selective conversion processes to produce renewable fuels and chemicals from plant biomass, and is instead used for heat and power due to its inherent recalcitrance to enzymatic degradation and heterogeneity. However, some microbes have evolved effective lignin depolymerization strategies by employing multiple oxidative enzymes. Despite a significant number of biochemical studies on single lignin-degrading enzymes and multiple genomics studies that have identified the full range of potential oxidative enzymes within given model organisms, detailed understanding of lignin degradation by natural systems remains elusive. Large-scale proteomics studies are now urgently required to complement these previous biochemical and genomics studies on a range of lignin-degrading organisms. Moreover, knowledge of a broad diversity of lignin degradation systems will enable the development of effective lignin-degrading enzyme cocktails for biorefinery use, and enable deeper understanding of the natural turnover of lignin in the biosphere. Both of these ultimate goals are primary aspects of the Biosystem Dynamics and Design (BDD) Science Theme at EMSL and key aims of the DOE Office of Biological and Environmental Research's mission.To that end, we propose a multi-pronged study that will leverage the world-class proteomics capabilities of scientists and instruments in EMSL's BDD Science Theme, the advanced lignin characterization methodologies at the National Renewable Energy Laboratory (NREL), and collaborative, ongoing efforts in microbial lignin depolymerization between NREL and the Joint BioEnergy Institute (JBEI). The EMSL component of the proposed work will focus on proteomics analysis of the secretomes of multiple fungi and bacteria known to depolymerize lignin across a variety of environmental niches. All of the organisms in the proposed list are currently being explored for their viability to depolymerize various process-relevant lignin samples, and secretomes will be collected for proteomics analysis under conditions known to induce secretion of lignin-degrading enzymes. To understand the associated chemical changes in lignin, detailed analysis of both the residual and solubilized lignin is being conducted via multiple spectroscopic, imaging, chromatographic, and analytical methods at NREL. The results from the proposed, large-scale proteomics study will be closely coupled to these additional methods to shed light from the molecular to the cellular scale for the key biological process of lignin depolymerization, which is central to both carbon recycling on Earth and to the development of cost-effective renewable biofuels.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2014-10-01
End Date
2016-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members
Related Publications
Salvachua D., A. Werner, I. Pardo, K. Michalska, B.A. Black, B. Donohoe, and S.J. Haugen, et al. 2020. "Outer membrane vesicles catabolize lignin-derived aromatic compounds in Pseudomonas putida KT2440." Proceedings of the National Academy of Sciences of the United States of America 117, no. 17:9302-9310. PNNL-SA-149636. doi:10.1073/pnas.1921073117
Salvachua D, R Katahira, NS Cleveland, P Khanna, MG Resch, BA Black, SO Purvine, EM Zink, A Prieto, MJ Martinez, AT Martinez, BA Simmons, JM Gladden, and GT Beckham. 2016. "Lignin depolymerization by fungal secretomes and a microbial sink." Green Chemistry 18(22):6046-6062. doi:10.1039/C6GC01531J