الفهرس 
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Abstract
SUMMARY
The world energy scene is undergoing a period of transition. As the
inevitability of exhaustion of fossil fuels is becoming increasingly,
intensive efforts are exerted to find and use substitute for energy.
Bioethanol is one of the most substitute renewable fuels contributing to
the reduction of the global worming effect and negative environmental
impact. Bioethanol production utilized derivatives of food crops. In Egypt
sugar cane molasses is the mainly used as feed stock for bioethanol
production. However, molasses contains many biological and chemicals
inhibitors, without management of these lead to negative effect on ethanol
yield and fermentation efficiency. Also unsuitable storage for molasses
lead to deterioration in molasses’s characters, decrease in fermentable
sugar, and lead to negative effect on alcoholic fermentation efficiency. So
this study aimed to management the sugar cane molasses to get rid of
inhibitors for production of economic bioethanol. The obtained results
can be summarized in the following:
1- Physiochemical analysis of sugar cane molasses used in this studies
(from four sugar factories plus mixed sample of the four factories)
were done and the results appeared that the fermentable sugar of the
mixed sample was 47.1%.
2- Ten yeast strains of Saccharomyces cerevisiae were screened for
ethanol production from sugar cane molasses with 18% fermentable
sugar to select the most appropriate one which gives the highest
fermentation efficiency and ethanol yield.
3- Saccharomyces cerevisiae F-514 strain was the superior one and gave
the highest ethanol (8.98 %) and fermentation efficiency (81.71%).
4- The bacterial load in mixed molasses sample under study was 1.1×107
cfu/ml.
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5- Management of bacterial load by different five antibiotics
(Tetracycline, Penicillin, Virginomycin, Erethromycine and
Amoxicilline) and other four chemicals compounds (Potassium meta
bisulfate, Chlorine, Kamoran and Dupont fermasure) was examined.
6- Addition of 10 ppm of tetracycline or 5 ppm of erythromycin
increased the ethanol yield by 0.42 %.
7- Addition of 600 units/L of penicillin improved the ethanol yield by
0.47 %.
8- Addition of 1.5 ppm of virginiamycin attained maximum achievable
results in ethanol yield where, it increased ethanol yield by 0.52 %.
9- When 5 ppm of amoxicillin was added to fermentation medium gave
renewable increased in ethanol yield by only 0.32 %.
10- Addition of 75 ppm of potassium meta bisulfate increased the ethanol
yield by 0.42 %.
11- Application of 50 ppm of chlorine in ethanol fermentation increased
ethanol yield by 0. 22 %.
12- Using 2 ppm of kamoran in ethanol fermentation for controlling
bacteria led to increase in ethanol yield by 0.47 %.
13- Using 40 ppm of dupont fermasure was more suitable for controlling
bacterial contamination in ethanol fermentation and increased ethanol
yield by 0.60 %.
14- Fresh prepared pure inoculum at 5 % size of fermentation mash and
pH of 3.5 – 4.5 were the more suitable for ethanol production from
molasses.
15- The results for management of bacterial load by the previous
compounds decrease in bacterial load and increase in fermentation
efficiency by 2.0 - 5.15 %.
16- Heavy metals concentrations in molasses which lead to critical
problem in fermentation media, if it is presented in unsuitable
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concentration, such as: Cd, Cu, Fe, Ni, Pb and Zn were determined at
0.74, 18.7, 115.0, 1.6, 6.4 and 22.0 ppm in addition to calcium at 6.6
% in mixed sample of molasses.
17- Treatments the heavy metals content in sugar cane molasses to
improve bioethanol fermentation by using Heating, Centrifugation,
Sulfuric acid and Phosphoric acid were examined.
18- Heating and centrifugation were sufficient to decrease Ca with less
effect on others metals.
19- Pretreatment of molasses by 0.3 % sulfuric acid after heating and
centrifugation decreased the content of various inhibitory metals ”Ca,
Cd, Cu, Fe, Ni, Pb and Zn” making molasses healthier for
fermentation by yeast strains F-514 and increase ethanol yield and
fermentation efficiency by 0.27 and 2.45%, respectively.
20- Phosphoric acid had less effect on lowering the level of heavy metals.
21- About 2.65 – 11.2% of fermentable sugars in molasses were lost
when stored under 40 – 60 °C. Most of losses happened in the first
two months especially at high temperature. Also losses in fermentation
efficiency from 2.1 to 12.72% was recorded when used molasses
storage at these conditions.
22- The suitable storage temperature must not exceed 40 °C and not for
long times to maintain the quality of molasses and avoid deterioration
(first in first out).
All the results proved that the management of chemical and microbial
contamination in sugar cane molasses in addition to store the
molasses in proper equipment, under suitable temperature and not for
long time lead to increase in ethanol yield and fermentation
efficiencies produces economic biofuel