biostudies-literatureUnknown111(24)Chung DEthanol is the most widely used renewable transportation biofuel in the United States, with the production of 13.3 billion gallons in 2012 [John UM (2013) Contribution of the Ethanol Industry to the Economy of the United States]. Despite considerable effort to produce fuels from lignocellulosic biomass, chemical pretreatment and the addition of saccharolytic enzymes before microbial bioconversion remain economic barriers to industrial deployment [Lynd LR, et al. (2008) Nat Biotechnol 26(2):169-172]. We began with the thermophilic, anaerobic, cellulolytic bacterium Caldicellulosiruptor bescii, which efficiently uses unpretreated biomass, and engineered it to produce ethanol. Here we report the direct conversion of switchgrass, a nonfood, renewable feedstock, to ethanol without conventional Proceedings of the National Academy of Sciences of the United States of America8931-6https://www.ebi.ac.uk/biostudies/studies/S-EPMC4066518biostudies-literatureDirect conversion of plant biomass to ethanol by engineered Caldicellulosiruptor bescii.PMC4066518Chung DGuss AMCha MWestpheling JfalseDirect conversion of plant biomass to ethanol by engineered Caldicellulosiruptor bescii.Ethanol is the most widely used renewable transportation biofuel in the United States, with the production of 13.3 billion gallons in 2012 [John UM (2013) Contribution of the Ethanol Industry to the Economy of the United States]. Despite considerable effort to produce fuels from lignocellulosic biomass, chemical pretreatment and the addition of saccharolytic enzymes before microbial bioconversion remain economic barriers to industrial deployment [Lynd LR, et al. (2008) Nat Biotechnol 26(2):169-172]. We began with the thermophilic, anaerobic, cellulolytic bacterium Caldicellulosiruptor bescii, which efficiently uses unpretreated biomass, and engineered it to produce ethanol. Here we report the direct conversion of switchgrass, a nonfood, renewable feedstock, to ethanol without conventional 2014-01-01T00:00:00Z2014 Jun2025-04-21T20:04:08.541Z2019-03-27T01:30:36ZS-EPMC40665182488962510.1073/pnas.1402210111