Monolignol biosynthesis pathway

Primary author: Parvaneh Ahmadvand
Faculty sponsor: ChulHee Kang

Primary college/unit: Arts and Sciences
Campus: Pullman


Biomass as a renewable carbon source for the generation of biofuels and biomaterials has become increasingly important in the quest for sustainable development. Plant secondary cell walls, which have a complex structure consisting of cellulose, hemicellulosic polysaccharides and lignin, constitute the majority of plant biomass. At the step of refinery, in the different chemical and physical processes, these various polymers are separated. Polysaccharides are hydrolyzed to fermentable sugars, whereas the lignin can be used as composites, nanoparticles and carbon fibers.There are there types of lignin: H (soft), G (semi-hard), S(hard).Of the several enzymes in the phenylpropanoid pathway, 4-coumaroyl-CoA ligase (4CL) is the central enzyme. Sorghum bicolor, the fifth most important cereal crop, is a plant that is a candidate for producing large volumes of biomass, in part because its tolerance for drought and a wide pH range. The brown midrib (BMR) is a genetic mutation that results in a forage with a reduced lignin content, increased protein content and higher palatability. The research is aimed at obtaining a better understanding of those Bmr2 and its mutations through their structural characteristics. Based on enzymatic assays, analysis of kinetics, a plausible mechanism for its broad substrate specificity will be proposed. Also, in the final step of lignification, Peroxidase and Laccase catalyze the oxidative radicalization, followed by combinatorial radical coupling. This will open a new perspective on understanding the catalytic process and innovative ways to increase the amount of H and G lignin and decrease the amount of S lignin so that cellulose can be more easily accessed for biofuel production.