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Sinsupha Chuichulcherm Soumitro Nagpal Ludmila Peeva Andrew Livingston 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2001,76(1):61-68
This work reports a novel system for the treatment of acidic metal‐containing wastewaters, the Extractive Membrane Bioreactor–Sulfate‐Reducing Bacteria (EMB‐SRB) system. In this system, hydrogen sulfide is produced in the bioreactor by the sulfate‐reducing bacteria, transfers through a dense phase membrane, and precipitates metal ions in the wastewater. The non‐porous membrane prevents the SRB from having direct contact with the toxic metals, extremes of pH, or high salinity in the wastewater. Silicone rubber, which is permeable to H2S but virtually impermeable to ionic species in the system, was used as a membrane. The rate of mass transfer of H2S across the membrane was studied and found to be well described by a resistances‐in‐series model. kov values vary in the range 5 × 10−6 –10 × 10−6 ms−1 1 depending on the membrane thickness. A continuous EMB–SRB system was operated and more than 90% (w/v) of the Zn2+ present in a wastewater was removed. A film of metal precipitate was found to build up on the inside (wastewater) side of the membrane, and became the dominant resistance contributing to the overall mass transfer coefficient during operation. © 2001 Society of Chemical Industry 相似文献
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Jarun Chutmanop Sinsupha Chuichulcherm Yusuf Chisti Penjit Srinophakun 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(7):1012-1018
BACKGROUND: An inexpensive and readily available agroindustrial substrate such as rice bran can be used to produce cheap commercial enzymes by solid‐state fermentation. This work investigates the production of food‐grade proteases by solid‐state fermentation using readily available Thai rice bran. RESULTS: A local strain of Aspergillus oryzae (Ozykat‐1) was used to produce proteases. Rice bran used alone proved to have poor substrate morphology (insufficient porosity) for satisfactory solid‐state fermentation. A certain amount of wheat bran was necessary to improve the morphology of the substrate. The following variables affected protease production: substrate composition, initial moisture content and initial pH. A high protease activity (∼1200 U g−1 dry solids) was obtained on a substrate that had a wheat bran to rice bran ratio of 0.33 by dry weight, a moisture content of 50%, initial pH of 7.5, and incubation temperature of 30 °C. CONCLUSION: Nutritionally, rice bran used alone was as good a substrate as mixed bran for producing protease, but rice bran had poor morphological characteristics for consistent fermentation. A substrate that had a wheat bran to rice bran ratio of 0.33 by dry weight was best for producing protease. Copyright © 2008 Society of Chemical Industry 相似文献
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