title: Enzymatic transformation of nonfood biomass to starch.
abstract: The global demand for food could double in another 40 y owing to growth in the population and food consumption per capita. To meet the world's future food and sustainability needs for biofuels and renewable materials, the production of starch-rich cereals and cellulose-rich bioenergy plants must grow substantially while minimizing agriculture's environmental footprint and conserving biodiversity. Here we demonstrate one-pot enzymatic conversion of pretreated biomass to starch through a nonnatural synthetic enzymatic pathway composed of endoglucanase, cellobiohydrolyase, cellobiose phosphorylase, and alpha-glucan phosphorylase originating from bacterial, fungal, and plant sources. A special polypeptide cap in potato alpha-glucan phosphorylase was essential to push a partially hydrolyzed intermediate of cellulose forward to the synthesis of amylose. Up to 30% of the anhydroglucose units in cellulose were converted to starch; the remaining cellulose was hydrolyzed to glucose suitable for ethanol production by yeast in the same bioreactor. Next-generation biorefineries based on simultaneous enzymatic biotransformation and microbial fermentation could address the food, biofuels, and environment trilemma.
authors.affiliation: Biological Systems Engineering Department, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
authors.forename: Chun
authors.initials: C
authors.lastname: You
authors.forename: Hongge
authors.initials: H
authors.lastname: Chen
authors.forename: Suwan
authors.initials: S
authors.lastname: Myung
authors.forename: Noppadon
authors.initials: N
authors.lastname: Sathitsuksanoh
authors.forename: Hui
authors.initials: H
authors.lastname: Ma
authors.forename: Xiao-Zhou
authors.initials: XZ
authors.lastname: Zhang
authors.forename: Jianyong
authors.initials: J
authors.lastname: Li
authors.forename: Y-H Percival
authors.initials: YH
authors.lastname: Zhang
mesh_terms: D000688:Amylose / Q000378:metabolism; D001671:Biochemistry / Q000379:methods*; D018533:Biomass; D002482:Cellulose / Q000378:metabolism; D003013:Clostridium / Q000201:enzymology; D005502:Food; D005936:Glucans / Q000378:metabolism; D005959:Glucosidases / Q000737:chemistry / Q000378:metabolism*; D006868:Hydrolysis; D060328:Magnetic Phenomena; D009154:Mutation / Q000235:genetics; D053758:Nanoparticles / Q000648:ultrastructure; D006005:Phosphorylases / Q000737:chemistry; D010802:Phylogeny; D011198:Solanum tuberosum / Q000201:enzymology; D013213:Starch / Q000378:metabolism*; D040681:Structural Homology, Protein; D020124:Thermotoga maritima / Q000201:enzymology
chemical_list: D005936:Glucans; D002482:Cellulose; D013213:Starch; D000688:Amylose; D006005:Phosphorylases; D005959:Glucosidases