Fermentative Butanol Production by ClostridiaFermentative Butanol Production by Clostridia

By Ajay KumarBy Ajay Kumar

Energy and Environment Fusion Technology Center (E2FTC)Department of Energy Science TechnologyMyongji University , South Korea

Fermentative Butanol Fermentative Butanol Production by ClostridiaProduction by Clostridia

Sang Yup Lee Sang Yup Lee et al.,et al., Biotechnology Biotechnology and Bioengineering, Vol. 101, No. 2, and Bioengineering, Vol. 101, No. 2,

October 1, 2008 (Review)October 1, 2008 (Review)

IntroductionIntroduction

Butanol (butyl alcohol and 1-butanol)Butanol (butyl alcohol and 1-butanol) C4H9OH (MW 74.12)C4H9OH (MW 74.12) Colorless liquid with a distinct odorColorless liquid with a distinct odor Miscible with organic solvents and partly Miscible with organic solvents and partly

miscible with watermiscible with water

Properties of butanolProperties of butanol

Melting point (Melting point (00C) -89.3C) -89.3 Boiling point (Boiling point (00C) 117.7 C) 117.7 Ignition temperature (Ignition temperature (00C) 35C) 35 Flash point (Flash point (00C) 365C) 365 Density at 20 Density at 20 00C (g/mL) 0.8098C (g/mL) 0.8098 Critical pressure (hPa) 48.4Critical pressure (hPa) 48.4 Critical temperature (Critical temperature (00C) 287C) 287

Market of butanolMarket of butanol

Estimated that 10–12 billion pounds Estimated that 10–12 billion pounds produced annually (Donaldson et al., 2007), produced annually (Donaldson et al., 2007),

Accounts for 7–8.4 billion dollar market at Accounts for 7–8.4 billion dollar market at current price.current price.

Projected market expansion of 3% per year Projected market expansion of 3% per year (Kirschner, 2006).(Kirschner, 2006).

ApplicationApplication

Used in the form of butyl acrylate and methacrylate Used in the form of butyl acrylate and methacrylate esters used in latex surface coating, enamels and esters used in latex surface coating, enamels and lacquers (Kirschner, 2006). lacquers (Kirschner, 2006).

Derivatives of butanol are butyl glycol ether, butyl Derivatives of butanol are butyl glycol ether, butyl acetate and plasticizers. acetate and plasticizers.

Excellent diluent for brake fluid formulations Excellent diluent for brake fluid formulations Solvent for the manufacturing of antibiotics, Solvent for the manufacturing of antibiotics,

vitamins and hormonesvitamins and hormones

Why ButanolWhy Butanol

Sufficiently similar characteristics to gasoline to be Sufficiently similar characteristics to gasoline to be used directly in any gasoline engine without used directly in any gasoline engine without modification and/or substitution modification and/or substitution

Butanol is superior to ethanol as a fuel additive in Butanol is superior to ethanol as a fuel additive in many regards:many regards:

(i) higher energy content, (i) higher energy content,

(ii) lower volatility, (ii) lower volatility,

(iii) less hydroscopic (thus does not pick up water), (iii) less hydroscopic (thus does not pick up water),

(iv) less corrosive (Du¨rre, 2007).(iv) less corrosive (Du¨rre, 2007).

Chemical Synthesis of ButanolChemical Synthesis of Butanol

Oxo synthesis,Oxo synthesis, Reppe synthesis, Reppe synthesis, CrotonaldehydehydrogenationCrotonaldehydehydrogenation

nn-butanol pathway -butanol pathway

Industrial production of butanolIndustrial production of butanol

Clostridium acetobutylicumClostridium acetobutylicum C. beijerinckii,C. beijerinckii, C. saccharobutylicum, C. saccharobutylicum, C. saccharoperbutylacetonicum are primary C. saccharoperbutylacetonicum are primary

solvent producers (Du¨rre, 2005). solvent producers (Du¨rre, 2005).

Simplified metabolism of biomass by Simplified metabolism of biomass by solventogenic clostridia.solventogenic clostridia.

Butanol fermentationButanol fermentation

Upstream and Upstream and Downstream processingDownstream processing pHpH TemperatureTemperature

Fermentation SubstratesFermentation Substrates

Raw materials including Raw materials including molasses, molasses, whey permeate, whey permeate, corn (Ezeji and Blaschek, 2007; Ezeji et al., 2007c; corn (Ezeji and Blaschek, 2007; Ezeji et al., 2007c;

Jones and Woods, 1986; Qureshi et al., 2008). Jones and Woods, 1986; Qureshi et al., 2008). low cost waste products such as starch-based waste low cost waste products such as starch-based waste

packing peanutspacking peanuts agricultural wasteagricultural waste low-grade glycerollow-grade glycerol

Solvent ToxicitySolvent Toxicity

Clostridial cellular metabolism ceases in the Clostridial cellular metabolism ceases in the presence of 20 g/L or more solventspresence of 20 g/L or more solvents

They found that 0.1–0.15 M butanol caused They found that 0.1–0.15 M butanol caused 50% inhibition of both cell growth 50% inhibition of both cell growth

Sugar uptake rate by negatively affecting the Sugar uptake rate by negatively affecting the ATPase activityATPase activity

Butanol Production by Other Butanol Production by Other MicroorganismsMicroorganisms

gene knock-out system for C.acetobutylicumgene knock-out system for C.acetobutylicum The mutant E. coli BW25113The mutant E. coli BW25113 Bacillus subtilis andBacillus subtilis and S. cerevisiae (Donaldson et al., 2007).S. cerevisiae (Donaldson et al., 2007).

Strategies for the development of an integrative bioprocess for butanol Strategies for the development of an integrative bioprocess for butanol production.production.

Metabolic Engineering of C. acetobutylicumMetabolic Engineering of C. acetobutylicumATCC 824ATCC 824

The objectives of metabolic engineering The objectives of metabolic engineering Enhanced butanol production with respect to the final Enhanced butanol production with respect to the final

concentration and productivity,concentration and productivity, Increased butanol (solvent) tolerance, Increased butanol (solvent) tolerance, Extended substrate utilization range,Extended substrate utilization range, Engineering the metabolic network for better Engineering the metabolic network for better

medium design, increased butanol yield on carbon medium design, increased butanol yield on carbon source, source,

Selective production of butanol instead of mixed Selective production of butanol instead of mixed acids/solvents productionacids/solvents production

Advanced Fermentation TechniquesAdvanced Fermentation Techniques

Batch reactorsBatch reactors Fed-batch reactorsFed-batch reactors Immobilized cell reactorImmobilized cell reactor

Recovery and In Situ SeparationRecovery and In Situ Separation

Traditional distillation processTraditional distillation process Pervaporation,Pervaporation, Adsorption, Adsorption, Liquid–liquid extraction,Liquid–liquid extraction, Gas stripping, andGas stripping, and Reverse osmosis have been developed to Reverse osmosis have been developed to

improve recovery performance and reduce improve recovery performance and reduce costs (Du¨rre, 1998)costs (Du¨rre, 1998)

pervaporationpervaporation

liquid–liquid extraction liquid–liquid extraction (perstraction(perstraction

gas strippinggas stripping

Future ProspectsFuture Prospects

Development of new fermentation and Development of new fermentation and recovery processes based on the metabolically recovery processes based on the metabolically engineered strainengineered strain

securing low price substrates for the processessecuring low price substrates for the processes

Biobutanol:The Next Big BiofuelBiobutanol:The Next Big Biofuel