ethanol production from sugar beet pulp - ndsu - north dakota

North Dakota State Universitywww.ndsu.edu/bioopportunities

Ethanol Production from Sugar Beet Pulp

Sugar beet plant

Impa

ct

• 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

Challenges

Bioproduct Research Laboratory

Working with sugar beet pulp

Analyzing carbohydrates and ethanol

Glucose21%

Arabinose 21%

Galactose5%

Xylose2%

Galcturonic Acid21%

Protein11%

Ash4%

Other15%

Cellulose

HemicellulosePectin

Sugar Beet Pulp

Arabinose and Galacturonic Acid Glucose

Cellulose

Ethanol

Pectinases & Hemicellulases

Cellulases

EnzymaticHydrolysis

FermentationProcess

Escherichia coli Saccharomyces cerevisiae

Flow chart of ethanol production procedure from sugar beet pulp

Sugar beet pulp composition