Dissertation
Manganese Assisted Fungal Treatment of Lignocellulosic Biomass for Biofuels Production
Washington State University
Doctor of Philosophy (PhD), Washington State University
12/2019
DOI:
https://doi.org/10.7273/000005569
Abstract
This dissertation study explored the effect of manganese addition on fungal treatment for improving enzymatic hydrolysis of different lignocellulosic feedstocks. The main topics included investigating destruction of lignocellulose structures and changes in biomass compositions, revealing the mechanism of enhanced preferential delignification by Mn addition, and developing an effective Mn assisted fungal treatment (MAFT) for improving biomethane yield. First, the effects of Mn addition on treatment of wheat straw and poplar with Phanerochaete chrysosporium were investigated. After 28 d treatment, ~50% sugar yield was obtained from the treated wheat straw and poplar with Mn addition of 0.01 mM/g biomass, which was 4-8 folds increase over the biomass treated only with fungus. The increased sugar yield of the treated biomass resulted from the combined effects of selective lignin degradation, reduced cellulose consumption, and destruction of the biomass structure after Mn addition. The Mn-assisted treatment was further tested with another fungus, Ceriporiopsis subvermispora. Approximately 85% sugar yield was obtained. Analysis of the compositional and structural characteristics of the biomass indicated that the key factors that led to high sugar yield were the enhanced degradation of lignin and minimal cellulose consumption. The mechanism of delignification by Mn-assisted C. subvermispora was related to be an increased activity of manganese peroxidases (MnPs) that led to preferential degradation of S-lignin units via breakdown of I? -O-4 ether linkages. Finally, the effective MAFT (C. subvermispora) was used to treat biomass for maximizing biomethane yield with reduced treatment times. MAFT effectively improved the biodegradability of wheat straw and corn stover up to ~97% after 14 d treatment. The corresponding methane yield was ~310 L/kg volatile solids (VS), which was 1.4-folds higher than that of the untreated samples. This study suggests a possible pretreatment method for producing sugar and biomethane from lignocellulose. It also addresses knowledge gaps pertaining to preferential delignification by fungus enhanced by Mn addition and improved digestibility of biomass.
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Details
- Title
- Manganese Assisted Fungal Treatment of Lignocellulosic Biomass for Biofuels Production
- Creators
- Xiao Fu
- Contributors
- Shulin Chen (Chair)David Roger Gang (Committee Member) - Washington State University, Biological Chemistry, Institute ofHaluk Beyenal (Committee Member) - Washington State University, Chemical Engineering and Bioengineering, School ofBin Yang (Committee Member) - Washington State University, Biological Systems Engineering, Department of
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Systems Engineering, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 156
- Identifiers
- 99901054232701842
- Language
- English
- Resource Type
- Dissertation