Enhanced production of lactic acid with reducing excess sludge by lactate fermentation
| Autor: | Yoshihito Shirai, Hiroaki I. Ogawa, Tomohiko Shimazu, Takayuki Yoshimura, Toshinari Maeda |
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| Rok vydání: | 2009 |
| Předmět: |
Environmental Engineering
Sucrose Sewage biology Health Toxicology and Mutagenesis Colony Count Microbial food and beverages biology.organism_classification Pollution Lactic acid chemistry.chemical_compound Activated sludge Wastewater chemistry Biochemistry Fermentation Environmental Chemistry Lactic Acid Food science Waste Management and Disposal Lactic acid fermentation Bacteria Sludge |
| Zdroj: | Journal of Hazardous Materials. 168:656-663 |
| ISSN: | 0304-3894 |
| DOI: | 10.1016/j.jhazmat.2009.02.067 |
| Popis: | The development of a facile technology for utilizing effectively and/or reducing excess sludge is one of the urgent problems since a large quantity of sewage sludge is formed by activated sludge processes. Excess sludge containing 50mM sucrose was fermented at 50 degrees C using endogenous bacteria in excess sludge, resulting in a high lactic acid production (8.45 g/L) and in an increased sludge reduction (38.2%). Conversion rate to lactic acid was up to 106.0% by standard fermentation at 50 degrees C compared to 43.8% at 30 degrees C and this phenomenon that conversion rate was higher was observed only at 50 degrees C as the fermentation at less or more than 50 degrees C had lower conversion rate than that at 50 degrees C. Lactic acid bacteria increased at 50 degrees C during 1-d fermentation whereas the number of total viable bacteria only increased slightly, indicating that lactic acid bacteria in sludge at 50 degrees C were preferentially able to utilize the sucrose for producing lactic acid. Finally, pH-vibration fermentation at 50 degrees C enabled to completely consume residual sucrose in the normal fermentation, resulting in the maximum production of lactic acid. Lactate fermentation by a purely cultured lactic acid bacterium TS1 with autoclaved excess sludge containing 50mM sucrose had more than 100% of conversion rate to lactic acid, indicating that a part of sludge was converted into lactic acid during the fermentation. Our technique is useful as a facile engineering for reducing excess sludge concomitantly with producing lactic acid by lactate fermentation. |
| Databáze: | OpenAIRE |
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