Effects of castor oil on Saccharomyces cerevisiae growth and activities during batch anaerobic fermentation
Saccharomyces cerevisiae is the most effective and safest microorganism in ethanol fermentation by involving sugar as substrate. It has many unique properties including fast growth rate, efficient glucose repression, efficient ethanol production and a tolerance for environment stresses such as hig...
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| Main Author: | |
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| Format: | Final Year Project Report |
| Language: | English English |
| Published: |
Universiti Malaysia Sarawak, (UNIMAS)
2014
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| Subjects: | |
| Online Access: | http://ir.unimas.my/id/eprint/34136/3/Effects%20of%20castor%20%C2%A0%2824pgs%29.pdf http://ir.unimas.my/id/eprint/34136/6/Huang%20Chai%20H.pdf http://ir.unimas.my/id/eprint/34136/ |
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| Summary: | Saccharomyces cerevisiae is the most effective and safest microorganism in ethanol fermentation by
involving sugar as substrate. It has many unique properties including fast growth rate, efficient glucose
repression, efficient ethanol production and a tolerance for environment stresses such as high ethanol
concentration. However, the growth and fermentative activities of yeast cell is inhibited by ethanol that
accumulates in fermentation broth. It is because high concentration of ethanol is toxic to the yeast cell.
Therefore, ethanol produced should be removed from fermentation broth. This study emphasized on the
effects of castor oil on S. cerevisiae growth and activities during batch anaerobic fermentation. As performed
by preliminary studies, castor oil has its capability to acts as selective ethanol-water separator. Four different
glucose concentrations with and without castor oil were examined for optimum glucose concentration, in
term of yeast's growth and ethanol production. Based on the results, the optimum glucose concentration for
effective ethanol production was 10% glucose concentration. Almost-all glucose (100.00 g/1) was consumed
by 8.05 x 10° cell/ml of yeast cell and converted into 86.27% Theoretical Ethanol Yields. Furthermore, the
survival of S. cerevisiae in broth with castor oil was higher than broth without castor oil, where 8.05 x 10°
cell/ml was higher than 6.20 x 10° cell/ml at 72 hours. Meanwhile, ethanol yield in broth with castor oil was
lower than broth without castor oil due to the absorption of ethanol by castor oil. It can lead to the reduction
of ethanol and indirectly reduce the toxicity of ethanol to the yeast cell. Hence, castor oil was assistance to
the growth and ferrnentative activities of S. cerevisiae. |
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