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Production of lignin-peroxidase and manganese-peroxidase is the hallmark of basidiomycetes and is often used to assess basidiomycete activity, especially in biotechnology applications. [38] Most white-rot species also produce laccase, a copper-containing enzyme that degrades polymeric lignin and humic substances.
Lignin is found to be degraded by enzyme lignin peroxidases produced by some fungi like Phanerochaete chrysosporium. The mechanism by which lignin peroxidase (LiP) interacts with the lignin polymer involves veratrole alcohol , which is a secondary metabolite of white rot fungi that acts as a cofactor for the enzyme.
Lignin-modifying enzymes benefit industry as they can break down lignin; a common waste product of the paper and pulp industry. These enzymes have been used in the refinement of poplar as lignin inhibits the enzymatic hydrolysis of treated poplar and Lignin-modifying enzymes can efficiently degrade the lignin thus fixing this problem. [4]
Although laccase is known to crosslink AX, under the microscope it was found that the laccase also acted on the flour proteins. Oxidation of the ferulic acid on AX to form ferulic acid radicals increased the oxidation rate of free SH groups on the gluten proteins and thus influenced the formation of S-S bonds between gluten polymers. [13]
Lignin confers structural integrity to plants. Lignin is so heterogeneous and so recalcitrant that its value is almost exclusively measured as a fuel. hemicellulose is composed of branched polysaccharides. A particular problem is that hemicellulose is covalently linked to lignin, usually through ferulic acid component of the
Flax seeds and sesame seeds contain high levels of lignans. [1] [8] The principal lignan precursor found in flaxseeds is secoisolariciresinol diglucoside.[1] [8] Other foods containing lignans include cereals (rye, wheat, oat and barley), soybeans, tofu, cruciferous vegetables (such as broccoli and cabbage), and some fruits (particularly apricots and strawberries). [1]
As PR proteins are produced when plant tissue is stressed, various ways of stress signaling is used to "bait" the plant into expressing PR genes for identification. Useful stressors include an actual infection or simply defense signals such as salicylate and methyl jasmonate .
The dissolved hemicelluloses and lignin after delignification are concentrated in evaporation and separated to produce hemicellulose fraction suitable for fermentation into ethanol or conversion to biochemicals. The separated lignin is sulfur-free and used in high-end applications replacing fossil aromatics. [8]