Improving lignocellulosic biofuel production by CRISPR/Cas9-mediated lignin modification in barley

• Main Authors: Hoang Nguyen Tran, P. (Author), Jung, J.H (Author), Kim, H.-Y (Author), Lee, J.H (Author), Lee, S.-M (Author), Won, H.J (Author)
• Format: Article
• Language: English
• Published: Blackwell Publishing Ltd 2021
• Subjects: antioxidant; barley; Barley; Bioethanol; Bio-ethanol production; biofuel; biomass; Biomass; caffeic acid O-methyltransferase; Caffeic acid o-methyltransferase; Cell wall composition; cellulose; Cellulosic ethanol; CRISPR/Cas9; Ecology; Environmental conditions; Ethanol; Feedstocks; Hordeum; lignin; Lignin; Lignin Content; lignin modification; Lignin modifications; lignocellulosic biofuel; lignocellulosic biomass; Lignocellulosic biomass; Lignocellulosic feedstocks; Lignocellulosic residues; Morphological variation; polysaccharide; Production; Saccharification
• Online Access: View Fulltext in Publisher

 Barley is a major cereal crop with a wide ecological range, and its lignocellulosic residues have the potential to be used as a feedstock for various purposes, including biofuel production. Lignocellulosic biomass is an abundant renewable source of carbon energy. However, its heterogeneous properties and intrinsic recalcitrance caused by cell wall lignification have lowered the biorefinery efficiency. The reduced lignin content and/or altered lignin structure have been desirable traits for lignocellulosic feedstock. We report the reduction of lignin content in barley by CRISPR/Cas9-mediated mutagenesis of caffeic acid O-methyltransferase 1 (HvCOMT1), the lignin biosynthetic gene responsible for lignin syringyl unit formation. The transgene-free, homozygous HvCOMT1 mutant was generated and analyzed for its cell wall composition, saccharification efficiency, and bioethanol production performance. The mutant had 14% lower total lignin content and 34% higher fermentable glucose recovery rate, compared to the wild-type (WT). The bioethanol concentration and yield from the hydrolysates of the mutant biomass were 14.3 g/L and 0.46 g/g total sugar, respectively. This result was 34% and 12% higher than those obtained from WT (10.7 g/L and 0.41 g/g total sugar). Under controlled environmental conditions, the overall growth performance of the HvCOMT1 mutant was similar to WT, with no distinct morphological variations between them. The HvCOMT1 mutant barley could offer improved quality lignocellulosic feedstock for efficient lignocellulosic biofuel production. © 2021 The Authors. GCB Bioenergy Published by John Wiley & Sons Ltd