19 articles
AFEX pretreatment
AFEX pretreatment, also called ammonia fiber expansion, is a thermochemical process treating lignocellulosic biomass with liquid ammonia under pressure, developed at Michigan State University for cellulosic ethanol production.
Cellulase
Cellulase is any enzyme that breaks down cellulose into glucose, produced mainly by the fungus Trichoderma reesei and used in saccharification of lignocellulosic biomass for cellulosic ethanol production.
Cellulosic ethanol
Cellulosic ethanol, or second-generation bioethanol, is ethanol made from lignocellulosic biomass such as corn stover, bagasse, and straw via pretreatment, enzymatic hydrolysis, and fermentation; commercial plants largely closed, and EPA waived 2025 volumes.
Clostridium ljungdahlii
Clostridium ljungdahlii is an anaerobic, rod-shaped acetogenic bacterium, first described in 1993, that converts synthesis gas mainly into acetate and ethanol. It was the first bacterium discovered to metabolize syngas components and produce ethanol.
Consolidated bioprocessing
Consolidated bioprocessing (CBP) is a cellulosic ethanol process in which enzyme production, biomass hydrolysis, and fermentation of hexose and pentose sugars occur in a single step by one microorganism, proposed in 1996.
Dilute acid pretreatment
Dilute acid pretreatment is a biomass pretreatment method that heats lignocellulosic material with dilute sulfuric acid to hydrolyze hemicellulose, making cellulose accessible to enzymes for ethanol production.
Dilute ammonia pretreatment
Dilute ammonia pretreatment is a chemical pretreatment for lignocellulosic biomass in which dilute aqueous ammonia selectively removes lignin, increasing fermentable sugar release for ethanol production.
Dry milling (ethanol production)
Dry milling, also called the dry-grind process, is the dominant method of producing fuel ethanol from corn in the United States, accounting for about 90% of U.S. ethanol output.
Enzymatic hydrolysis
Enzymatic hydrolysis is the enzyme-driven breakdown of cellulose in plant biomass into soluble sugars, under mild conditions, and serves as the central conversion step in biochemical cellulosic ethanol production.
Hot water pretreatment
Hot water pretreatment, also called liquid hot water (LHW) pretreatment, cooks lignocellulosic biomass in pressurized water at 160–240 °C to dissolve hemicellulose and make cellulose accessible for bioethanol production.
Ionic liquid pretreatment
Ionic liquid pretreatment uses ionic liquids, salts that melt below 100 °C, to dissolve lignocellulosic biomass so cellulose, hemicellulose, and lignin can be converted to fuels like ethanol.
Pentose fermentation
Pentose fermentation is the microbial conversion of five-carbon sugars, chiefly xylose and arabinose, into ethanol, allowing lignocellulosic biomass to be used for fuel alcohol production.
Saccharification
Saccharification is the step in starch and biomass processing where heat and enzymes convert polymeric carbohydrates into simple fermentable sugars, chiefly glucose, often combined with fermentation in one vessel.
Separate hydrolysis and fermentation
Separate hydrolysis and fermentation (SHF) is a cellulosic ethanol process in which enzymatic hydrolysis of pretreated biomass and fermentation of the released sugars run in separate reactors, each at its own optimum temperature.
Simultaneous saccharification and fermentation
Simultaneous saccharification and fermentation (SSF) is a biofuel process in which cellulose is broken down by enzymes and fermented to ethanol in a single reactor.
Steam explosion
Steam explosion, also called autohydrolysis, is a pretreatment that heats lignocellulosic biomass with high-pressure steam and rapidly releases the pressure, rupturing cell walls for enzyme conversion.
Thin stillage
Thin stillage is the liquid coproduct of grain ethanol production, separated from whole stillage by centrifugation after distillation; most is recycled as process water or evaporated into feed.
Vacuum fermentation
Vacuum fermentation is a fermentation process operated at subatmospheric pressure so volatile products like ethanol boil off continuously, relieving product inhibition and raising ethanol productivity up to 12-fold.
Very high gravity fermentation
Very high gravity fermentation is a process-intensification strategy in industrial ethanol production that ferments mashes above 250 g/L sugar to exceed 15% ethanol, raising plant output while cutting water use and distillation energy costs.