Recovery of Organic Acids From Fermentation Broths Southern Bio-Products Conference March 4-6, 2004 Beau Rivage Resort Biloxi, MS Tim Eggeman, Ph.D., P.E. Dan Verser, Ph.D. ZeaChem Inc.

Organic Acids - Today Organic AcidPrice, $/lb (100% Basis) US Demand, MM lb/yr Common Route Formic0.4650Synthetic Acetic0.425,286Synthetic Oxalic0.3817Synthetic Propionic Synthetic Lactic Fermentation Tartaric3.007Fermentation Succinic1.003Synthetic Maleic Synthetic Adipic0.701,725Synthetic Citric Fermentation

Points of View Sugars: –Inexpensive –Under-Utilized –More Sustainable Synthetic Routes will Eventually be Displaced Platform Viewpoint is Under-Utilized Biology plus = Better Technology and Chemistry Market Diversification

Generic Platform

C 2 Platform

Issues in Recovery pH of Broth –Unreactive Species at Near Neutral pH –Commodity Scale Production is Constrained by Need to Avoid Salt Coproduction Dilute Broths –Evaporating Water is Expensive –Prefer Selective Methods for Removing Organic Acids from Water

Effect of pH

pH Options Low pH Fermentation Neutral pH Fermentation –Direct Acidification –Amine Complex Formation –Other Bipolar Electrodialysis Esterases

Lactic Acid - Traditional Fermentation Hydrolysis Esterification Direct Acidification Lime Lactic Acid Water Ester Water Alcohol Sulfuric Acid Gypsum Sugars

Direct Acidification US Demand for Lactic Acid = 176 MM lb/yr, Gypsum Coproduct = 252 MM lb/yr !!!

Lactic Acid – Amine Extraction (From: Baniel, A.M. et. al., US Pat. 5,510,526)

Citric Acid – Lime/Acid FermentationPrecipitation AcidificationCrystallization Lime Calcium Citrate SugarsResidue Citric Acid Sulfuric Acid Water Gypsum

Citric Acid – Amine Extraction FermentationCrystallization Forward Extraction Back Extraction Residue Citric Acid Sugars Water

Formic Acid CarbonylationHydrolysis CO Methanol Formic Acid Water Methyl Formate Methanol

Some Common Themes Eliminating Salt Coproduction is Difficult –Microbiology –Careful Selection of Cations and Recovery Scheme Common Purification Methods –Amine Extraction –Esterification

Routes to Ethanol

Lab Status - Fermentation Lab Scale Fermentation –Strain: Moorella Thermoacetica ATCC –Media: Glucose+Corn Steep Liquor Batch Results –First Run: 28 g/l acetate –Goal: g/l acetate, yield = 85 + % of theoretical

Lab Status - Recovery Lab Scale –Amine Complex Formation w/ CaCO 3 Precipitation –Extraction of Amine Complex –Esterification Results to Date –97 + % CaCO 3 Recovery –Excellent Extraction (K D > 2) –Ester Yield: 75% of Theoretical

Conclusions Technical Issues –pH and Avoidance of Salt Coproduction –Dilute Broths Advantages of Platform Viewpoint –New Routes Based on Biology and Chemistry –Market Diversification

Acknowledgements US Department of Energy - Inventions and Innovation Program (Grant Number DE- FG36-03GO13010) Support by US DOE Does Not Constitute an Endorsement by US DOE of the Views Expressed in this Presentation