Industrial Biotechnology
Badr
Objectives
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Be able to produce of ethyl alcohol by using fermentation techniques.
Be able to detect of ethyl alcohol by chemical test.
Be able to distillate the production by simple distillation method.
I. Introduction
Ethanol fermented from renewable sources for fuel or fuel additives are known as
bio-ethanol. Additionally, the ethanol from biomass-based waste materials is considered
as bio-ethanol.
Both yeasts and bacteria have been used for the production of ethanol. Among the
bacteria, the most widely used organism is Zymomonas mobilis. Saccharomysis
cerevisiae is the most commonly used yeast but Kluyveromyces fragilis has also been
employed.
Under aerobic conditions and the presence of high glucose concentration,
Saccharomysis cerevisiae grow well but produces no alcohol. Under anaerobic condition,
however, growth slows and pyruvate from glycolytic pathway is split with pyruvate
decarboxylase into acetaldehyde and Co2. Ethanol is then produced from acetaldehyde by
reduction with alcohol dehydrogenase.
Ethanol is produces in three steps, each of which must be optimized: 1- Preparation of
nutrient solution; 2- fermentation; 3- distillation of ethanol.
II. Preparation of the nutrient solution:
Materials:
a. For 1L of Sucrose nutrient broth you need:
Sucrose
MgSo4
KH2Po4
(NH4)2So4
Yeast extract
20%
0.5g
1g
5g
1g
Adjust pH to 4.
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Industrial Biotechnology
Badr
a.1 For 1L of Glucose nutrient broth you need:
Glucose
Peptone
KH2Po4
Yeast extract
10g
5g
2g
20g
Procedure:
1- You will prepare from (a.) 700 ml and from (a.1) 70 ml only.
2- Autoclave at 121°c, 1.5 atm for 15- 20 min.
3- For I.a.1 add 7g of baker's yeast aseptically after cooling then Incubate the media in
water bath at 37°c for 1- 2 hr for activation.
4- Add 70 ml of glucose nutrient broth to 700 ml of sucrose nutrient broth aseptically.
5- Finally incubate the whole media at 37°c for one week.
III. Detection of ethyl alcohol by chemical test:
Materials and procedures:
1- Add 5 ml of K2Cr2O7 to 1 ml of H2So4 then heat slowly.
2- Add 1 ml from the fermented media.
Results:
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IV. Distillation the production:
A method of separating two or more liquids, by changing the equilibrium balance
between them. Ethanol boils at 78.5° C, so it's pretty easy to get the water out.
Heat the alcohol/water mixture, then when the ethanol evaporates, it's caught and
condensed, producing a higher concentration of alcohol. It can be run through the still
several times, each time producing a higher concentration.
Procedure:
Set up a distillation apparatus as in Fig. 8.1
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