Nature Plants
Author:
Keywords:
Science & Technology, Life Sciences & Biomedicine, Plant Sciences, CELL-WALL, ALKALINE-DEGRADATION, FERULIC ACID, LIGNIN, POPLAR, IDENTIFICATION, FRACTIONATION, SACCHARIFICATION, DEHYDROGENASE, VISUALIZATION, Arabidopsis, Biomass, Cell Wall, Cellulose, Curcuma, Curcumin, Glucose, Ligases, Lignin, Plant Proteins, Plants, Genetically Modified, Polyketide Synthases, Temperature, 0607 Plant Biology, 0703 Crop and Pasture Production, 3103 Ecology, 3108 Plant biology
Abstract:
Lignin is the main cause of lignocellulosic biomass recalcitrance to industrial enzymatic hydrolysis. By partially replacing the traditional lignin monomers by alternative ones, lignin extractability can be enhanced. To design a lignin that is easier to degrade under alkaline conditions, curcumin (diferuloylmethane) was produced in the model plant Arabidopsis thaliana via simultaneous expression of the turmeric (Curcuma longa) genes DIKETIDE-CoA SYNTHASE (DCS) and CURCUMIN SYNTHASE 2 (CURS2). The transgenic plants produced a plethora of curcumin- and phenylpentanoid-derived compounds with no negative impact on growth. Catalytic hydrogenolysis gave evidence that both curcumin and phenylpentanoids were incorporated into the lignifying cell wall, thereby significantly increasing saccharification efficiency after alkaline pretreatment of the transgenic lines by 14-24% as compared with the wild type. These results demonstrate that non-native monomers can be synthesized and incorporated into the lignin polymer in plants to enhance their biomass processing efficiency.