Recovery of Organic Acids From Fermentation Broths

Southern Bio-Products ConferenceMarch 4-6, 2004

Beau Rivage ResortBiloxi, MS

Tim Eggeman, Ph.D., P.E.Dan Verser, Ph.D.

ZeaChem Inc.

Organic Acids - Today

Organic Acid Price, $/lb (100% Basis)

US Demand,

MM lb/yr

Common

Route

Formic 0.46 50 Synthetic

Acetic 0.42 5,286 Synthetic

Oxalic 0.38 17 Synthetic

Propionic 0.49 202 Synthetic

Lactic 0.80 176 Fermentation

Tartaric 3.00 7 Fermentation

Succinic 1.00 3 Synthetic

Maleic 0.42 478 Synthetic

Adipic 0.70 1,725 Synthetic

Citric 0.75 600 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 andChemistry Market Diversification

Generic Platform

RCOH

O

OrganicAcid

RCH

O

Aldehyde

RCH2OH

Alcohol

RCOR

O

Ester

CH2

Olefin

RCR

O

Ketone

R

C2 Platform

CH3COH

O

AceticAcid

CH3CH

O

Acetaldehdye

CH3CH2OH

Ethanol

CH3COCH2CH3

O

EthylAcetate

CH2

Ethylene

CH3CCH3

O

Acetone

CH2

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

0

10

20

30

40

50

60

70

80

90

100

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

pH

% D

isso

ciat

ion

Dissociated AcidProtonated Acid

pKa = 4.75

BasicAcidic

Neutral

CH3COH

O

CH3CO-

O

H++

ProtonatedAcid

DissociatedAcid

pH Options

• Low pH Fermentation

• Neutral pH Fermentation– Direct Acidification– Amine Complex Formation– Other

• Bipolar Electrodialysis• Esterases

Lactic Acid - Traditional

Fermentation

Hydrolysis

EsterificationDirectAcidification

Lime

LacticAcid

Water

Ester

Water

Alcohol

SulfuricAcid

Gypsum

Sugars

Direct Acidification

Fermentation: O H2 Ca(Lac) Ca(OH) OHC 2226126

Re-acidification: 4422 CaSO HLac2 SO H Ca(Lac)

Overall: O H2 CaSO HLac2 SO H Ca(OH) OHC 244226126

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

Fermentation Precipitation

Acidification Crystallization

Lime

CalciumCitrate

Sugars Residue

CitricAcid

SulfuricAcid Water

Gypsum

Citric Acid – Amine Extraction

Fermentation Crystallization

Fo

rwar

d E

xtr

act

ion

Back E

xtraction

Residue

CitricAcid

Sugars

Water

Water

Formic Acid

Carbonylation HydrolysisCO

Methanol

FormicAcid

Water

Methyl Formate

Methanol

HCOH

O

H2O

CO CH3OH HCOCH3

O

Carbonylation:

Hydrolysis:

Net:

HCOCH3

O

HCOH

O

CO H2O

+

+

+

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

F e rm e n ta tio n :

E s te r if ic a tio n :

H y d ro g e n a tio n :

N et:

D e x tro se 3 A c e tic A c id

3 E th y l A c e ta te + 6 H 6 E th a n o l2

3 A c e tic A c id + 3 E th a n o l 3 E th y l A c e ta te + 3 H O2

D ex trose + 6 H 3 E th an ol + 3 H O22

ZeaC hem Indirect R oute

D ex trose 2 E th a n o l + 2 C O 2

D irect Ferm entation

Lab Status - Fermentation

• Lab Scale Fermentation– Strain: Moorella Thermoacetica ATCC 39073– Media: Glucose+Corn Steep Liquor

• Batch Results– First Run: 28 g/l acetate– Goal: 35-50 g/l acetate, yield = 85+% of theoretical

Lab Status - Recovery

• Lab Scale– Amine Complex Formation w/

CaCO3 Precipitation– Extraction of Amine Complex– Esterification

• Results to Date– 97+% CaCO3 Recovery– Excellent Extraction (KD > 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