ethanol production from sugar beet pulp - ndsu - north dakota

www.ndsu.edu/bioopportunities Ethanol Production from Sugar Beet Pulp Impact • North Dakota and Minnesota produce 15.8 million tons of sugar beets per year, which is more than 50% of total U.S. production • 750,000 dry tons of low-value pulp remain after sucrose extraction in North Dakota and Minnesota • North Dakota and Minnestoa could produce 75 million to 90 million gallons of ethanol per year if all carbohydrates in beet pulp (70-75%) can be used Scott Pryor, Nurun Nahar, and Rachel Rorick NDSU Dept of Agricultural and Biosystems Engineering To determine the technical feasibility of sequential enzyme treatments to produce separate fermentable sugar streams to increase cellulose loading rates and ethanol titers from sugar fermentation. Separate sugar streams also may be fermented into other higher-value fuels or chemicals. Objective • Minimal additional costs for harvest, storage or transportation of sugar beet pulp • Elimination of drying and pressing processes for pulp; energy for drying is estimated at $80/ton • Low lignin content (<2%) leads to elimination of costly thermochemical pretreatment required for most other biomass feedstocks • Sugar beet pulp has a high carbohydrate content consisting mainly of cellulose, hemicellulose and pectin • Cellulose, hemicellulose and pectin components are readily hydrolyzed by commercial enzymes Beneﬁts • Relatively small production scale on a processing plant basis • Relatively low level of cellulose content • Large pectin levels not typical of most lignocellulosic biomass • Hemicellulose component has different composition than most biomass feedstocks Challenges Bioproduct Research Laboratory Working with sugar beet pulp Analyzing carbohydrates and ethanol Glucose 21% Arabinose 21% Galactose 5% Xylose 2% Galcturonic Acid 21% Protein 11% Ash 4% Other 15% Cellulose Hemicellulose Pectin Sugar Beet Pulp Arabinose and Galacturonic Acid Glucose Cellulose Ethanol Pectinases & Hemicellulases Cellulases Enzymatic Hydrolysis Fermentation Process Escherichia coli Saccharomyces cerevisiae Flow chart of ethanol production procedure from sugar beet pulp Sugar beet pulp composition

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North Dakota State Universitywww.ndsu.edu/bioopportunities

Ethanol Production from Sugar Beet Pulp

Sugar beet plant

Impa

• NorthDakotaandMinnesotaproduce15.8milliontonsofsugarbeetsperyear,whichismorethan50%oftotalU.S.production

• 750,000drytonsoflow-valuepulpremainaftersucroseextractioninNorthDakotaandMinnesota

• NorthDakotaandMinnestoacouldproduce75millionto90milliongallonsofethanolperyearifallcarbohydratesinbeetpulp(70-75%)canbeused

ScottPryor,NurunNahar,andRachelRorickNDSUDeptofAgriculturalandBiosystemsEngineering

Todeterminethetechnicalfeasibilityofsequentialenzymetreatmentstoproduceseparatefermentablesugarstreamstoincreasecelluloseloadingratesandethanoltitersfromsugarfermentation.Separatesugarstreamsalsomaybefermentedintootherhigher-valuefuelsorchemicals.O

bjec

tive

• Minimaladditionalcostsforharvest,storageortransportationofsugarbeetpulp

• Eliminationofdryingandpressingprocessesforpulp;energyfordryingisestimatedat$80/ton

• Lowlignincontent(<2%)leadstoeliminationofcostlythermochemicalpretreatmentrequiredformostotherbiomassfeedstocks

• Sugarbeetpulphasahighcarbohydratecontentconsistingmainlyofcellulose,hemicelluloseandpectin

• Cellulose,hemicelluloseandpectincomponentsarereadilyhydrolyzedbycommercialenzymes

Benefits

•Relativelysmallproductionscaleonaprocessingplantbasis

• Relativelylowlevelofcellulosecontent

•Largepectinlevelsnottypicalofmostlignocellulosicbiomass

•Hemicellulosecomponenthasdifferentcompositionthanmostbiomassfeedstocks