Discovering Functional Diversity of Lytic Polysaccharide Monooxygenases from the Thermophilic Fungus Myceliophthora Thermophila and Their Application in Lignocellulosic Biomass Degradation

Abstract

Although lytic polysaccharide monooxygenase (LPMO) genes are highly abundant in the genomes of ascomycetes and basidiomycetes, their biological roles in single species for lignocellulose degradation remain unclear. Herein, transcriptomic analysis of the efficient biomass degrader Myceliophthora thermophila grown on corn straw revealed a high number and transcript abundance of LPMOs and glycoside hydrolases (GHs) in response to lignocellulose degradation. To gain a deeper understanding of the roles of LPMOs, phenotypic characterization of single gene deletion mutants and catalytic properties of recombinant LPMOs were valuated. Single gene deletion mutants of these highly expressed AA9 LPMOs exhibited no significant reduction in growth rate on corn straw compared to the wild-type strain. Functional characterization of these AA9 LPMOs showed significant differences in oxidative regioselectivity, catalytic activity, and substrate specificity. Notably, MtLPMO9G exhibited dual catalytic activities, degrading cellulose and xylan through oxidation and hydrolysis reactions, respectively. Moreover, synergistic actions between AA9 LPMOs and GHs from various families on enzymatic saccharification of corn straw with alkaline pretreatment showed that MtLPMO9G and MtLPMO9H increased the catalytic efficiency of cellulolytic GHs by 28 to 242%. These findings demonstrate great application potential of MtLPMO9G and MtLPMO9H in designing LPMO-containing cellulase cocktails for efficient enzymatic saccharification of lignocellulosic biomass.

Exploring the partial degradation of polysaccharides: Structure, mechanism, bioactivities, and perspectives

“…Additionally, as a key enzyme in cellulose degradation, glucosidase has the potential to reduce our dependence on fossil fuels by converting cellulose into biofuels. For example, cellulose can be hydrolyzed by a synergistic effect of endo‐1,4‐β‐glucanases (EC 3.2.1.4), exo‐1,4‐β‐glucanase (EC 3.2.1.91), and β‐glucosidase (EC 3.2.1.21) (Qin et al., 2023; Venezia et al., 2020).…”

“…For some stubborn polysaccharides, it is still difficult to explain how GHs cleave polysaccharide chains in a crystalline environment. Therefore, some scholars have proposed that there is a substrate destruction factor that can participate in the degradation of stubborn polysaccharides together with GH (Qin et al., 2023; Reese & Siu, 1950). Lysis of polysaccharide monooxygenases (LPMOs) is a powerful mononuclear Cu enzyme (EC 1.14.99.53–56) from the carbohydrate auxiliary activities family.…”

Corn straw-saccharification fiber improved the reproductive performance of sows in the late gestation and lactation via lipid metabolism

“…2 Group B: 6% HFLSCSSF added in the basal diet to replace corn meal and wheat bran. 3 Group C: 6% MFMSCSSF added in the basal diet to replace corn meal and wheat bran. 4 Group D: 6% LFHSCSSF added in the basal diet to replace corn meal and wheat bran.…”

“…Therefore, it is crucial to develop new feed resources to replace the traditional feedstuffs. Lignocellulose with approximately 75% polysaccharide is a low-cost renewable resource composed of cellulose, hemicellulose, and lignin, which has the potential to be converted to animal feed (3)(4)(5).…”

“…CP, crude protein; DE, digestible energy; Ca, calcium; P, phosphorus; NDF, neutral detergent fiber; ADF, acid detergent fiber. 1 HFLSCSSF: high-fiber and low-saccharification CSSF.2 MFMSCSSF: medium-fiber and medium-saccharification CSSF 3. LFHSCSSF: low-fiber and high-saccharification CSSF 4.…”