Biobutanol production

1. Biobutanol Production fromBiobutanol Production from
Agricultural ResidueAgricultural Residue
Course: Special Topics On Bioenergy
Course Advisor: Dr. Han Thi Hiep
Presenter: Clinton Chayan Dhar
ID: 21850142
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2. IntroductionIntroduction
 Butanol is an alcohol which can be used as a
transport fuel with properties very similar to
gasoline. Biobutanol refers to biofuel produced
from renewalable resources. Production of
butanol by fermentation utilizes a number of
organisms including Clostridium acetobutylicum
or Clostridium beijerinckii. Butanol can be
produced by the traditional acetone-butanol-
ethanol (ABE) fermentation – the anaerobic
conversion of carbohydrates by clostridia into
acetone, butanol and ethanol.
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3. BiobutanolBiobutanol
 In recent years, there has been renewed interest in
biobutanol production for transportation fuel. Compared to
ethanol, butanol offers several unique advantages as a
substitute for gasoline because of higher energy content and
higher hydrophobicity.
 Economic analysis have demonstrated that the fermentation
substrate is one of the most important factors that influenced
the price of butanol, therefore, many studies have been
focused on the use of renewable and low-cost substrates
such as agricultural residues as substrates for ABE
production.
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4. Why Biobutanol?Why Biobutanol?
 Distribution:As less corrosive and having lower water solubility than
ethanol, butanol can be distributed via existing pipelines and
distribution stations.
 Blending ability with gasoline and diesel: Compared to ethanol,
blending is possible in higher concentrations without any vehicle
retrofitting. Thereby the share of renewable components in the final
fuel mixture could be increased.
 Energy content, octane values and air to fuel ratio: Values are
closer to gasoline compared to ethanol. Fuel economy (km/L) is better
than with ethanol.
 Usability: Compared to ethanol, the lower heat of vaporization
enables the easier starting of a motor in cold weather and decreases
the ignition problems.
 Safety. Butanol is safer to use and handle compared to ethanol due
to the lower vapor pressure and higher flash point. In addition, butanol
generates lower amounts of volatile organic compound (VOC)
emissions in internal combustion engines.
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5. Milestones of Biobutanol ProductionMilestones of Biobutanol Production
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6. Isomer of Biobutanol and UseIsomer of Biobutanol and Use
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7. Microbiology of BiobutanolMicrobiology of Biobutanol
FermentationFermentation
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 Bio-butanol can be produced from biomass with the
help of two major Microorganism.
These are:
1. Clostridia e.g. C. acetobutylicum and C. beijerinckii
2. Enteric Bacteria e.g. Escherichia coli

8. ClostridiaClostridia
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•Butanol (and acetone, ethanol, and isopropanol) are
naturally formed by a number of clostridia. Clostridia are
rod-shaped, spore-forming gram positive bacteria and
typically strict anaerobes. Solventogenic (solvent
producing) clostridia can utilize a large variety of substrates
from monosaccharides including many pentoses and
hexoses to polysaccharides.
•The development of molecular techniques for
solventogenic clostridia (i.e., C. acetobutylicum and C.
beijerinckii) in combination with recent advances in
fermentation techniques has resulted in the development of
an integrated ABE fermentation system for simultaneous
production and removal of ABE from the fermentation
vessel. These improvements have resulted in reduction of
toxicity, improved productivity, increased solvent yield, and
improved carbohydrate utilization.

9. Enteric BacteriaEnteric Bacteria
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Butanol production by Clostridium in mixed-
product fermentation is well known.
However, in this fermentation, it is difficult to
control butanol yield, and furthermore, due
to the relatively unknown genetic system
and complex physiology
of the microorganism, it is also difficult to
achieve optimal biobutanol production.
Thus, there is strong interest to produce
butanol from a user-friendly organism.
Escherichia coli is a well-characterized
microorganism with a set of readily available
tools for genetic manipulation and its
physiological regulation is well-studied.

10. Phases of Biobutanol ProductionPhases of Biobutanol Production
Pathway.Pathway.
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The metabolic pathways of ABE-producing clostridia
consist of two distinct characteristic phases.
These are:
1.Acidogenesis
2.solventogenesis

11. Metabolic Pathway of BiobutanolMetabolic Pathway of Biobutanol
ProductionProduction
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1. pf1B (pyruvate-ferrodoxin
oxidoreductase)
2. acetyl transferase
3. hbd (3- hydroxyl- CoA
dehydrogenase)
4. crt (crotonase)
5. bcd (butyryl-CoA
dehydrogenase)
6. adhE (butyraldehyde
dehydrogenase)
7. bdhAB (butanol
dehydrogenase).

12. Bioreactor Configuration andBioreactor Configuration and
Biobutanol YieldBiobutanol Yield
Batch process
 The batch process is the most commonly studied method of
fermentation for butanol production due to simple operation
and reduced risk of contamination.
 However, the productivity achievable in a batch reactor is low
due to the lag phase, product inhibition as well as down time
for cleaning, sterilizing, and filling. Under batch operation
conditions, C. beijerinckii BA101 was able to produce 18–33
g/L ABE in 72 h of fermentation using glucose or starch as
the substrate
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13. Bioreactor Configuration andBioreactor Configuration and
Biobutanol YieldBiobutanol Yield
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Fed-batch fermentation:
 Fed-batch fermentation is applied to the butanol production to
avoid substrate inhibition and to increase cell mass. In fed-
batch process, the reactor is initiated in a batch mode with a
low substrate concentration (noninhibitory to the culture) and
a low medium volume, and then the culture volume increases
in the reactor over time. Since butanol is toxic to C.
acetobutylicum or C. beijerinckii cells, the fed-batch
fermentation technique cannot be applied unless one of the
novel product recovery techniques is applied for
simultaneous separation of product. As a result of substrate
reduction and reduced product inhibition, greater cell growth
occurs and reactor productivity is improved.

14. Bioreactor Configuration andBioreactor Configuration and
Butanol YieldButanol Yield
 In this process, the reactor is initiated in a batch mode and
cell growth until the cells are in the exponential phase. While
the cells are in the exponential phase, the reactor is fed
continuously with the medium and a product stream is
withdrawn at the same flow rate as the feed, thus keeping a
constant volume in the reactor. This mode of fermentation
runs much longer than in a typical batch process. This
technique of butanol production by C. beijerinckii BA101 was
investigated and resulted in a productivity rate of 1.74 g/L h-
1.
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Continuous culture technique

15. Other ReactorOther Reactor
 Immobilized cell reactors and cell recycle reactors have
also been applied to butanol production in order to increase
productivity 40–50 times as compared to batch reactors
Reactor productivity can be improved by increasing the cell
concentration in the reactor.
 Membrane cell recycle reactor is another option to improve
fermentation productivity. Pierrot et al. (1986) studied a
hollow-fiber ultrafiltration to separate and recycle cells in a
continuous system.However, fouling of the membrane with
the fermentation broth was a major obstacle of this system.
suggested a way to overcome this problem by allowing only
the fermentation broth to undergo filtration by using the
immobilized cell system.
 However, fermentation must be combined with a suitable
product removal technique.
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16. Production of ABE from different fermentationProduction of ABE from different fermentation
and production removal system.and production removal system.
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17. Production of ABE from different fermentationProduction of ABE from different fermentation
and production removal system.and production removal system.
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18. Agricultural-Residues as SubstrateAgricultural-Residues as Substrate
 In order to reduce the butanol production cost, various
renewable and economically feasible substrates such as
agricultural residues have been used as the fermentation
substrates including wheat straw, corn waste, or rice straw.
Other than the use of corn, liquefied corn meal and corn
steep liquor (a byproduct of corn wet milling process that
contains nutrients leached out of corn during soaking) has
been also used.
 a combination of fermentation of these novel substrate to
butanol with product recovery may be the economical
approach.
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19. Important Considerations inImportant Considerations in
Biobutanol FermentationBiobutanol Fermentation
Pretreatment:
 The clostridia are not able to efficiently hydrolyze fiber-rich
agricultural residues. Therefore, agricultural biomass must be
hydrolyzed to simple sugars using economically developed
methods. Dilute sulfuric acid pretreatment can be applied to
agricultural residues for hydrolysis.
 Another pretreatment method for wheat straw is the use of
alkali pretreatment and enzyme hydrolysis. There are
enzymes available that can hydrolyze cellulose to glucose
that can, in turn, be fermented to butanol.
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20. Important Considerations inImportant Considerations in
Biobutanol FermentationBiobutanol Fermentation
Operating pH
 The pH of the medium is very important for butanol
fermentation. In acidogenesis, rapid formation of acetic and
butyric acids causes a decrease in pH. Solventogenesis
starts when pH reaches a critical point, beyond which acids
are reassimilated and butanol and acetone are produced.
Therefore, low pH is a prerequisite for solvent production.
However, if the pH decreases below 4.5 before enough acids
are formed, solventogenesis will be brief and unproductive.
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21. Important Considerations inImportant Considerations in
Biobutanol FermentationBiobutanol Fermentation
Nutrients
 The additions of various organic materials to the basic
medium for production ABE by clostridia have been widely
practiced by supplementing organic nitrogen, amino acids,
vitamins and other compounds. The main substance for the
large-scale process was usually a very complex mixture of
carbohydrates and other carbonaceous and inorganic
compounds which differed greatly from one operation to
another. Clostridia require high negative redox potential to
produce butanol (and ethanol) and the supply of additional
reducing power results in increased butanol and ethanol
formation with reduced acetone formation.
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22. Important Considerations inImportant Considerations in
Biobutanol FermentationBiobutanol Fermentation
Operating Temperature
 The effect of temperature on the ABE production by C.
acetobutylicum has been studied in the range 25 to 40
degree C. It was found that the solvent yield decreased with
increasing temperature; seemingly because of a reduction in
acetone production.
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23. Techno-Economic Analysis ofTechno-Economic Analysis of
Butanol FermentationButanol Fermentation
 The substrate price is the most influential factor
affecting the price of butanol.
 ABE yield is another important factor which
influences the butanol production cost.
 There are other costs, for example: interest on the
borrowed capital, rate of return (profit), steam,
electricity, depreciation, maintenance and repair,
federal taxes, and insurance are also the major
factors contributing to the price of butanol.
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24. Limitations of ButanolLimitations of Butanol
FermentationFermentation
 The current method of biobutanol production, by
ABE fermentation and distillation, is too complex
and energy-intensive.
 The major problems of ABE fermentation include
product toxicity to the producing bacteria,
substrate-to-product conversion efficiency, the
ability to utilize an inexpensive substrate, and the
potential for culture degeneration.
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25. Future PossibilityFuture Possibility
 A process using extracellular hydrolysis by chemical or by
physical or by enzymes for pretreatment (is presently under
development for production of bioethanol) could be applied to
furnish lignocellulosic substrates for microbial conversion to
butanol.
 the new membrane technology should enable economic
production of butanol, a green fuel alcohol, from renewable
resources. Existing and future corn-to-ethanol plants could be
used for butanol production if the technology were proven to
be economical. In addition, the technology could be adopted
to replace petroleum-derived butanol and acetone.
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26. ConclusionConclusion
 Future research on biobutanol production shall focus to
achieve simultaneously high yield of products and recovery.
By using agricultural-residues as the substrate for economic
biobutanol production, the study should focus on mixed sugar
fermentation and inhibitory effects on different soluble
chemicals produced during pretreatment. Optimization of
fermentation conditions shall be considered for higher butanol
yield. Furthermore, further research and development,
especially in strain selection and genetic modification, as well
as in the downstream processing of the ABE are essential for
cost-effective butanol production.
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27. ReferenceReference
 © 2008 Society of Chemical Industry and John Wiley & Sons, Ltd | Biofuels, Bioprod.
Bioref. 2 :319–330 (2008); DOI: 10.1002/bbb
 Biobutanol Production from Agri-Residues,S. Yan, Bala subramanian S., R.D. Tyagi,
R.Y. Surampalli,and Tian C. Zhang: BIOENERGY AND BIOFUEL FROM BIOWASTES
AND BIOMASS.
 Bioenergy. http://dx.doi.org/10.1016/B978-0-12-407909-0.00001-8
 V. K. Gupta and M. G. Tuohy (eds.), Biofuel Technologies, DOI: 10.1007/978-3-642-34519-
7_17, Springer-Verlag Berlin Heidelberg 2013
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28. THANK YOU ALL
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