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Wednesday, September 4, 2013



ETHANOL FROM CELLULOSE Presentation Transcript:
1. Ethanol is a colorless, volatile and flammable liquid belonging to a group of organic chemicals known as alcohols.
It has a density of 0.789g/cm3, a boiling point of 78˚C and its structural formula is written as:

 2. Other names used to refer to ethanol include:
Absolute alcohol
Ethyl alcohol
Drinking alcohol
Grain alcohol
Ethyl hydrate
Ethyl hydroxide

3. Uses of Ethanol
As Fuel – to power motor vehicles or as an additive to gasoline to improve its octane rating.
Alcoholic beverages  – ethanol is the major constituent (with psychoactive effects) in alcoholic drinks.
As an antiseptic at concentrations of 62%v/v.
As a solvent – its found in several products such as markers, tinters and paint as it is one of the best solvents.
As a raw material in the production of plastics, acetic acid, perfumes, plasticizers, among others.

4. Methods of Production
Ethanol is usually produced by two methods:
Hydration of Ethylene
C2H4 + H2O → CH3CH2OH
2. Fermentation of sugar-containing plant parts like corn, sugar beets, sugar cane, e.t.c
C6H12O6 → 2CH3CH2OH + 2CO2

5. Cellulose
It is an organic polymer made up of linear chains of thousands of linked beta(1-4) D-glucose units. It is a major constituent of plant cell walls and forms approx. 45-60% of woody plants.
Its formula is written as:

6. Cellulosic Ethanol
Ethanol produced from cellulosic materials is referred to as cellulosic ethanol.
As explained earlier, cellulose is made up of linear chains of linked beta D-glucose molecules. Glucose molecules can be obtained from cellulose chains by hydrolysis. The glucose obtained can then fermented to form ethanol.

7. Examples of Cellulosic Materials include:
Switch Grass
Wood chips
Corn stover
Wheat straw

8. But Why Cellulosic Ethanol?
Most countries that produce ethanol in large quantities, such as Brazil, rely on food crops such as corn and sugar cane. This inevitably brings competition with food supply.
Cellulose presents an alternative to this since it is mainly contained in the non-food plant parts, that mostly go unutilised, e.g agricultural and forest residue.
Lignin, a waste product of this process, has high calorific value and can be used to fire boilers.

9. Methods of Producing Cellulosic Ethanol
There exist two methods of producing ethanol from cellulosic materials:

10. 1. Cellulolysis
This is also known as the biological approach and it involves five or six steps depending on the level of purity required.
The steps are…

11. i. Pretreatment
The purpose of pretreatment is to free cellulose from lignin( one of the plant polymers which acts as a seal ), exposing it for hydrolysis.
The methods used include:
Physical pretreatment (size reduction) e.g milling
Chemical pretreatment e.g acid hydrolysis, organosolv, ammonia fiber explosion.

12. ii. Cellulose Hydrolysis
This involves breakdown of the long chains of beta D-glucose to free glucose molecules. This process avails the sugar contained in cellulose for fermentation.
Its usually achieved by either of the following methods:
Enzymatic hydrolysis – cellulose enzymes are used to biologically break down cellulose to glucose.
Chemical hydrolysis – an acid, usually sulphuric acid, is used.

13. iii. Separation
The sugar formed from the hydrolysis process is separated from residual material such as lignin.

14. iv. Fermentation
Microbes are used to ferment the glucose formed into ethanol.
Cellulosic materials usually contain hemicellulose polymer. When this is hydrolysed, a 5-carbon sugar called xylose, is usually formed.
For this reason, microorganisms used for this process should be capable of fermenting xylose.

15. Commonly used microbes include:
Saccharomyces cerevisiae
Zymomonas mobilis
Escherichia coli



1. What is carbon sequestration?
Carbon sequestration refers to the process of capturing carbon dioxide from the atmosphere and storing it (usually in other forms of carbon) for a long period of time.

2. More specifically, it refers to:
Intentional removal of CO2 from the atmosphere and its deposition in a reservoir/carbon sink.
Removal of CO2 from flue gases (e.g in power/process plants) and its storage in a reservoir.
Natural cycling/exchange of carbon from the atmosphere to reservoir and vice versa (carbon cycle).

3. It is an established fact that global warming is on the rise.
This is mainly caused by an increase in greenhouse gases, of which CO2 forms a major part.
Studies have also shown that since the beginning of industrial revolution to 1992, CO2 levels in the atmosphere increased by 30%.
The main reasons attributed to this are change in land use and combustion of fossil fuels.

4. Global warming has negative effects on our planet, such as climatic changes and extreme weather which in turn cause floods, typhoons, a decrease in food production, among others.
The purpose of carbon sequestration is to alleviate global warming so as to avert the occurrence of dangerous/ extreme climatic changes.

5. The methods employed to effect carbon sequestration include…

6. Biological processes
Peat blocs – creating of new peat bogs or by augmenting existing ones.
Reforestation – trees and forest vegetation use CO2(photosynthesis)
Wetland Restoration – wetland soil acts as an important carbon sink.
Agriculture – growing crops act as a carbon sink.
Iron and urea fertilization in oceans

7. Physical processes
Bio-energy from biomass
Biomass burial
Ocean storage of dead biomass brought in by rivers
These processes prevent exposure of dead biomass to the atmosphere, which could otherwise result in release of carbon contained in it to CO2.

8. Chemical processes
Industrial Use – e.g in beverage industries.
Chemical Scrubbers – in process industries to prevent escape of CO2 to the atmosphere.


10. Biomass refers to the biological material obtained either from living plants or from plants that were recently living. Aboveground biomass therefore includes all plant matter above the soil surface, for instance:
Trees – parts above the soil; stem, leaves, branches.
Growing Crops – parts above the soil, excludes all parts below the soil.
Decaying agricultural and forest waste on the soil surface.

11. Aboveground biomass has a two-way effect on carbon sequestration…

12. On one hand;
Living plants utilize CO2 in photosynthesis, converting it into other forms of carbon useful for their growth.
This aids in carbon sequestration.

13. On the other hand;
Decaying plant matter on the soil surface loses carbon to the atmosphere in form of CO2
This has a reverse effect on carbon sequestration

14. 1. Type and density of vegetation
Different vegetation types have different potential of carbon sequestration.
For instance, tropical forests have been found to have a greater potential as compared to dry evergreen and mixed deciduous forests.

15. 2. Size of plants
Different plant sizes have different potential of carbon sequestration.
Plants that grow to greater sizes utilize more CO2 for their growth and thus they have a greater carbon sequestration potential than smaller plants.
For instance, trees have a greater potential than crops like beans or maize plants.

PPT On Biological Denitrification


Biological Denitrification Presentation Transcript:
1. Denitrification is the process of removing nitrate(NO3) or nitrites(NO2) from ground and/or surface waters by reducing them, in presence of a electron donor, to nitrogen gas(N2). The electron donor, usually carbon, is referred to as the energy source.

2. But isn’t nitrate important for life?
Nitrate is a form of nitrogen usually found in the soil. Most crops need nitrogen as it forms part of DNA and proteins in plant and animal cells. Hence in the right amounts, nitrogen is essential to all forms of life.
Crops usually obtain it by absorbing it in form of nitrates from the soil while animals get it from feeding on plants.

3. Major Sources include:
Nitrogen-fixation from atmosphere by lightning, leguminous plants & N-fixing bacteria.
Municipal waste water

4. Why then denitrify?
As a result of leaching, nitrates usually find their way to groundwater.
When found in concentrated amounts in ground water and surface water, such water can have harmful effects both to humans and animals if used for drinking.

5. Drinking water high in nitrates concentration results to an interference with one’s red blood cells ability to transport oxygen in the body.
The result to both humans and animals is an illness known as methemoglobinemia, mainly found in infants.
Hence there is need to monitor groundwater used for drinking and carry out de-nitrification if found to have excess nitrates.

6. The maximum limit, as set by the World Health Organization is:
For humans: 10 mg/ℓ NO3
For animals: 100 mg/ℓNO3

7. Apart from biological de-nitrification, are there other methods that can be used?

8. Other processes can be used such as:
1. Physical processes – Reverse osmosis, ion exchange and electrodialysis
2. Chemical de-nitrification

9. Advantages of Biological Denitrification:
High nitrate removal efficiency,
Moderate operating cost
High process stability and reliability
The process can be controlled with ease

10. Biological Denitrification Process
The raw water to be denitrified is fed into a bioreactor (with the presence of denitrifying bacteria-innoculum)
Most waste water to be denitrified contains enough carbon(energy) source for the process and thus with the right conditions, nitrates are converted to N2 gas through a number of reduction steps:

11. Nitrates are first converted into nitrites, then to nitric oxide, then to nitrous oxide and finally to nitrogen.

NO3- →NO2- → NO → N2O → N2

Nitric oxide, nitrous oxide and nitrogen are gaseous products and they can be safely released into the atmosphere.

12. Commonly used denitrifying bacteria include:

13. If water to be treated is deficient in dissolved carbon, then additional carbon(energy) source/ electron donor must be supplied.

14. Commonly used energy sources include:







15. Sawdust as an Energy Source
Research has shown that biodegradable solid waste can be used effectively as a carbon(energy) source.
Research carried out on the effectiveness of sawdust for raw water containing 100-200mgN/L, which is a probable value for groundwater, has shown nitrates removal of up to 100%
The usability of sawdust as a carbon source presents a great advantage since it is readily available as a waste product of the forest industry.

PPT On Pathology Of Diabetes


Pathology Of Diabetes Presentation Transcript:
1. What is diabetes?
Diabetes mellitus, or as it also known, simply diabetes, is a group of metabolic diseases. It occurs when a person has high blood sugar. It can happen either because of the lack of insulin production from the pancreas or because of the difficulty that cells show to respond to it.

2. What is diabetes?
The most common symptoms of high sugar in blood circulation is :
polyuria, which is frequent urination, 
polydipsia; the increased thirst
polyphagia; the increased hunger

3. Types of diabetes
There are three main types of diabetes mellitus (DM).
1) Type 1 DM 
2)Type 2 DM 
3) gestational diabetes  occurs when pregnant women without a previous diagnosis of diabetes develop a high blood glucose level. It may precede development of type 2 DM.

4. Type 1: Juvenile diabetes
This type of diabetes is the result of the body's failure to produce insulin. Treatment to this kind of disease is not an easy thing to do, as it requires regular injections of insulin or to wear and carry around an insulin pump. It is also known as "insulin-dependent diabetes mellitus" (IDDM) or "juvenile diabetes".

5. Type 2: Adult-onset diabetes
This type is the result of insuline resistance. In this case insulin can not be used properly from cells and sometimes it is combines with absolute insulin deficiency.This form is also known as non insulin-dependent diabetes mellitus (NIDDM) or "adult-onset diabetes".

6. Type 3:  Gestational diabetes
This form of diabetes occurs when pregnant women with no previous diagnosis of diabetes develop a high blood glucose level. It may precede to the development of type 2 diabetes.

7. More types…
Other forms of diabetes mellitus include:
1)congenital diabetes, which occurs because of genetic defects of insulin secretion, 
2) cystic fibrosis-related diabetes,
3) steroid diabetes because of high doses of glucocorticoids,
4) several forms of monogenic diabetes.

8. Pathology of diabetes
Insulin is a hormone that mainly regulates the uptake of glucose from the blood into cells and especially muscle and fat cells. That’s why insulin deficiency or insensitivity of its receptors is crucial in diabetes mellitus, no matter what form.

9. Humans can digest carbohydrates, and in particular those that are most common in food they consume in everyday life; starch, as well as some disaccharides (sucrose for example), are converted to simpler forms, usually to monosaccharide glucose, the most used carbohydrate energy source for the human body.

10. Insulin, the hormone we referred before, is released into the blood by beta cells (β-cells), which can be found in the islets of Langerhans in the pancreas. Insulin is released in response to high levels of blood glucose, typically after eating and is used to absorb glucose from the blood for consumption as fuel, for conversion to other molecules, or for storage.

11. If the available amount of insulin is insufficient or if cells don’t respond effectively to it (insulin insensitivity or resistance), or if insulin is defective by its construction and form, then glucose will not be absorbed properly by body cells, nor will it be stored appropriately. This problem can cause poor protein synthesis, persistent high levels of blood glucose, and other metabolic derangements, like acidosis.

12. Thank you for your attention
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