Studies of Cellulose and Starch Utilization and the Regulatory Mechanisms of Related Enzymes in Fungi

Abstract

Polysaccharides are biopolymers made up of a large number of monosaccharides joined together by glycosidic bonds. Polysaccharides are widely distributed in nature: Some, such as peptidoglycan and cellulose, are the components that make up the cell walls of bacteria and plants, and some, such as starch and glycogen, are used as carbohydrate storage in plants and animals. Fungi exist in a variety of natural environments and can exploit a wide range of carbon sources. They play a crucial role in the global carbon cycle because of their ability to break down plant biomass, which is composed primarily of cell wall polysaccharides, including cellulose, hemicellulose, and pectin. Fungi produce a variety of enzymes that in combination degrade cell wall polysaccharides into different monosaccharides. Starch, the main component of grain, is also a polysaccharide that can be broken down into monosaccharides by fungi. These monosaccharides can be used for energy or as precursors for the biosynthesis of biomolecules through a series of enzymatic reactions. Industrial fermentation by microbes has been widely used to produce traditional foods, beverages, and biofuels from starch and to a lesser extent plant biomass. This review focuses on the degradation and utilization of plant homopolysaccharides, cellulose and starch; summarizes the activities of the enzymes involved and the regulation of the induction of the enzymes in well-studied filamentous fungi.

Fungal pretreatment to enhance the yield of phytochemicals and evaluation of α‐amylase and α‐glucosidase inhibition usingCinnamomum zeylanicum(L.) quills pressurized water extracts

“…These species have been used quite extensively in cellulase production (Jamil, Ahmed and Al 2009; Wang et al . 2020). Moreover the fungus T. harzianum has shown higher activity in degrading cellulose than T. reesei (Delabona et al .…”

Estimation of glucosamine in biomass of Trichoderma reesei cultivated on lignocellulosic substrates

“…Results were compatible to using media with only hemicellulose (media with hemicellulose–cellulose–lignin as 1–0–0), or only cellulose (media with hemicellulose–cellulose–lignin as 0–1–0), or both hemicellulose and cellulose (media with hemicellulose–cellulose–lignin as 2–1–1, 1–1–0, and 1–2–1), containing the same content of carbohydrate (2.4%) but different compositions, showing different glucosamine content in biomass. This might be due to differences in the complexity of the required enzymes such as endo β‐1,4‐glucanase, cellobiohydrolase, and β‐glucosidase for cellulose digestion [34], and endo β‐1,4‐xylanase, β‐xylosidase, arabinase, acetyl xylan esterase, and α‐glucuronidase for hemicellulose digestion [35], while α‐amylase and α‐glucosidase were used for starch assimilation. Higher glucosamine contents in fungal cells were detected with media involving lignin (media with hemicellulose–cellulose–lignin as 1–0–1, 2–0–1, 1–1–1, 0–1–1, 1–2–2, 0–2–1, 1–0–2, 2–2–1, 2–1–2, and 1–1–3), while the lowest was obtained in media containing only lignin as lignocellulosic material (media with hemicellulose–cellulose–lignin as 0–0–1).…”

Fermentation Profile, Nutritional Value, and Microbial Population of C4 Grasses Silages with or Without Bacterial Additive

“…This fact is probably because the plastic bag (polyethylene) silos can present oxygen permeability, and most fungi are strictly aerobic. They can use sugars (glucose, sucrose, and maltose) and more complex compounds (starch, cellulose, and hemicellulose) as substrates for their growth (Wang et al, 2020).…”