Application of activated sludge as a complementary in bioethanol production
Introduction: Excess activated sludge contains large amounts of components such as phosphorus, nitrogen, and sulfur which can theoretically be used as a nutrient source in fermentation processes to produce value added materials. In the present study, the possibility to grow Saccharomyces cerevisiae...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
University of Isfahan
2015-06-01
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| Series: | Biological Journal of Microorganism |
| Subjects: | |
| Online Access: | http://uijs.ui.ac.ir/bjm/browse.php?a_code=A-10-367-1&slc_lang=en&sid=1 |
| Summary: | Introduction: Excess activated
sludge contains large amounts of components such as phosphorus,
nitrogen, and sulfur which can theoretically be used as a nutrient source in fermentation
processes to produce value added materials. In the present study, the possibility to grow Saccharomyces
cerevisiae and produce ethanol
on pretreated and untreated activated
sludge as a nutrient source was investigated. Materials and methods: In this article, Saccharomyces
cerevisiae, CEN.PK 113-7D, was used as an ethanol producer
microorganism. In order to release the organic matter of the sludge and increase the efficiency of ethanol production, four pretreatments, i.e. acidic, alkaline, thermal and ultrasonic were
performed on the sludge. The effectiveness of each pretreatment on biomass growth at aerobic
conditions was measured by CFU method.
Moreover, the yield of ethanol at anaerobic conditions was measured using gas-chromatography. Results: The highest biomass yield of
yeast on the wet sludge at aerobic conditions was obtained after alkaline pretreatment, in which the biomass concentration
increased from 1.2
105 (CFU/ml) to 1.5
106 (cell/ml) after 36 hour of cultivation. At
anaerobic conditions, the yield of ethanol on alkaline pretreated sludge was 0.11 g ethanol/g initial glucose. Additionally, by drying the sludge
and performing the alkaline pretreatment, the ethanol production was increased
up to 0.41 g ethanol/g initial glucose. Discussion and conclusion: The results showed that the excess activated sludge from wastewater treatment plants can be used as nutrient source for ethanol production. However, it needs
to be treated and alkaline pretreatment of dried sludge is suggested to produce a high
yield of ethanol. |
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| ISSN: | 2322-5173 2322-5181 |