ethanolfromcellulosemaboelgheit-130924064534-phpapp02
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ethanol from celluloseTRANSCRIPT
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Mohamed Mosaad Abo El-Gheit
MSc. Student, Applied Microbiology, SCU,
Ismailia, Egypt
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Contents: Biofuel
Types of Biofuel
1st and 2nd generation of Bioethanol
Lignocellulosic Biomass in Egypt
Composition of Lignocellulose
Pretreatment of Lignocellulose
Microbial Enzymatic Hydrolysis
Bioprocessing of Biomass
Cellulosic Activities in Actinomycetes
Microbial Consortia
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Biofuel: Energy from newly-growing plant
sources
CO2-neutral
alternative source of energy to the current traditional sources e.g. gasoline
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CO2 Neutral?
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1st Generation of Bioethanol
Sugars extract ferment
ethanol
sugarcane BRAZIL
(sucrose)
Sugars Hydrolyze (enzymes)
ferment ethanol
USA
(starch)
Cosgrove; 2005
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Types of Biofuel Solid animal wastes and agricultural residues can be
used as sources of energy by direct burning (primitive way)
Liquid Bioethanol C2H5OH ( fermentation of sugar)
Biodiesel (by saturation of vegetable oils)
Gas e.g. methane and biogas derived from organic wastes by anaerobic digestion
Organic wastes Heat energy Direct burning
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2nd Generation of Bioethanol
Cosgrove; 2006
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Lignocellulosic Biomass Agricultural Residues:
Source: Quantitative appraisal of biomass resource and their energy potential in Egypt; 2013
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Lignocellulosic Biomass: Energy crops: plants which grow at low cost, to make
biofuel.
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Composition of Lignocellulose Cellulose
Hemicelluloses
Lignin
Ash Extractives
Cellulose
Hemicellulose (both 5 and 6 carbon sugars)
(need modified microbe to convert to ethanol)
Ash Extractives
Lignin (phenols)
(6 carbon sugars)
Chapple, 2006; Ladisch, 1979, 2006
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Pretreatment
break down the shield formed by lignin and hemicellulose
Open the fiber structure
reduce the degree of polymerization of cellulose.
Source: Overview of biomass pretreatment for cellulosic ethanol production; 2009
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Pretreatment has been viewed as one of the most expensive processing steps within the conversion of biomass to fermentable sugar
Pretreatment methods maybe: physical, chemical or biological
Biological:
Adv. : no chemicals, no energy requirements, mild environmental conditions
Disadv.: slow, the activity of the microorganisms maybe not specific to lignin only!
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Pretreated Lignocellulose What is Pretreated Biomass?
increased surface area,
solubilization of cellulose,
redistribution of cellulose and lignin
Cellulose 35-50%
Hemicellulose 20- 35%
Lignin 5-30%
Microbial cellulose utilization fundamental and biotechnology; 2002
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Enzymatic Treatment Pretreated
Lignocellulose Pentoses and hexoses + lignin and lignin degradation
Enzymatic Hydrolysis
cellulose glucose
hemicellulose glucose + xylose+ other C5 and C6 sugars
Microbial cellulose utilization fundamental and biotechnology; 2002
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Microbial Enzyme system: Substrate cellulose + hemicellulose
Enzymes:
endoglucanases: cut at random internal sites along the cellulose/hemicellulose chain
exoglucanases: act at reducing and nonreducing ends
beta-glucosidase: break betaglucoside bond to form glucose
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Enzyme system
Cellulose Oligosaccharides (
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Lignocellulosic Activities of Actinomycetes According to Lynd et al (2002) there is a considerable
concentration of cellulytic capabilities among Actinomyceltales.
Actinomycetes are well known for their ability to decompose complex molecules, particularly lignocellulose components
Micromonospora spp and Strptomyces spp are well known for their decomposition ability on Biomass
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Actinomycetes and cellulytic activities
Growth Temp Speices mesophilic M. chalcea
mesophilic S. roseflavus
Mesophilic S. reticuli
Thermophilic Thermobifidia fusca
mesophilic Kibdelosporanguim Philippinenses
Most of actinomycete species can be isolated from both soil and water.
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Bioprocessing of cellulosic Biomass Steps (mediated events):
1) Cellulase production
2) Hydrolysis of cellulose/hemicellulose
3) Fermentation of cellulose hydrolysis products e.g. glucose
4) Fermentation of hemicellulose hydrolysis products other than glucose e.g. xylose
biomass
fuel
Microbial cellulose utilization fundamental and biotechnology; 2002
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Bioprocessing of cellulosic Biomass
This diagram shows the capability of consolidation or separation of mediate events (steps) of bioprocessing of Biomass Source: Microbial cellulose utilization fundamental and biotechnology; 2002
SHF: Separated Hydrolysis and Fermentation
SSF: Simultaneous Saccharification and Fermentation
SSCF: Simultaneous Saccharification and Cofementation
CBP: Consolidate Bioprocessing
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Consolidated Bioprocessing CBP In which all bioprocessing steps are combined together
as one process
Biomass processing technology has exhibited a trend toward increasing consolidation over time
Advantages Efficiency + Economically effective
CBP organisms:
Single organism
Community of organisms( symbiotic consortium)
(which is more efficient???)
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Symbiotic Consortium A community of organisms
i.e 2 or more organisms living in association
Symbiosis may be : mutualism, commensalism, o antagonism
Types:
Natural consortuim
Engineered consortuim
Genetically
Recombined natural capabilities i.e. ecological approaches
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Natural Consortium The main problem doesnt accumulate high levels
of biofuel why?
Biofuel molecules are molecules of energy
Biofuels represents an a pportunity for a new consortia member (organism) to exploit
Natural consortia tend to thermodynamically free energy of molecules till the lowest level
Be overcome by engineering consortia
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Models of microbial interactions in a consortuim (dual culture)
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Sequential utilization 2 oranisms M1 and M2
The fuel molecule (F1) is considered a waste product of M1. However, it is degraded by M2 as source of energy e.g. commensalism
No accumlation of fuel molecules
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Co-utilization M1 & M2 are competing to
utilize the substrate , producing fuel molecules
Competitive symbiosis i.e. controlled by inhibitors /activatiors
Fuel considered waste product of both organsims
There is accumulation of fuel
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Substrate transformation M1 acts on substrate converting
it to a form that can be utilized by M2
e.g. pretreatment of lignocellulosic material
mutualsim
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Product transformation M1 produces fuel products as
waste product
M2 act on fuel to convert it into an alternative fuel
Look like sequential utilization. However, the fuel molecules are converted to alternative fuel , not completely utilized