Graduate Program

Biological Sciences

Degree Name

Master of Science (MS)

Semester of Degree Completion

Spring 2024

Thesis Director

Thomas Canam

Thesis Committee Member

Barbara S. Carlsward

Thesis Committee Member

Eden L. Effert-Fanta

Abstract

The major limitation to producing biofuels from lignocellulosic biomass, such as miscanthus straw, is the difficulty in accessing fermentable carbohydrates encased in lignin. Traditional methods for separating lignin are economically and environmentally costly. Biological pretreatment using white-rot fungi, such as Trametes versicolor, has been demonstrated to potentially reduce the need for harsh chemical and physical pretreatment methods. Despite these efforts, the process of converting lignocellulose to ethanol remains financially challenging. To explore a potential co-product for the process, this study evaluated the efficacy of T. versicolor strain CM-101, known for producing the valuable medicinal macromolecule polysaccharide-K (PSK), as a pretreatment agent for miscanthus straw, comparing its performance to the biofuel-related strain 52J. Both strains were cultured on miscanthus straw for 5 weeks. Post-treatment analyses included lignin extractability, glucose yield, gene expression, and protein profiles. Results showed that miscanthus straw treated with strain CM-101 had similar levels of lignin extractability as well as glucose yields as strain 52J, with no significant difference in glucose concentrations between treated and untreated samples. Additionally, gene expression analysis indicated comparable levels of transcripts for lignin deconstruction (P450) and cellulose hydrolysis (endo-β-1,4-glucanase) genes with both strains. Overall, this study demonstrated that T. versicolor strain CM-101 is as effective as strain 52J in reducing the recalcitrance of miscanthus straw, suggesting that CM-101 could be used as a dual-purpose agent for biofuel pretreatment and as a source of a medically relevant co-product. The production of PSK from CM-101 in this scenario could provide an additional revenue stream, potentially improving the economic viability of lignocellulose-based biofuel facilities.

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