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Nitrogen removal bioreactor capable of simultaneous nitrification and denitrification applicable to industrial wastewater treatment
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Abstracts / Journal of Biotechnology 131S (2007) S242–S249
antioxidant selenoproteins, making it an essential micronutrient for animals, microorganisms, and some other eukaryotes (Birringer et al., 2002; Berken et al., 2002). In addition to the basic nutritional requirements for Se, it has become increasingly evident that Se also has potential health benefits. Anticarcinogenic properties of various organic forms of Se against certain types of cancer have been demonstrated (Reid et al., 2002; Whanger, 2002). However, excess Se can be toxic, and the observation that Se bioaccumulation is toxic to wildlife, has generated a surge of interest in phytoremediation of Se. The largest group of Se-hyperaccumulating plants belongs to the genus Astragalus (Fabaceae). Twenty-five species of Astragalus have been characterized as Se hyperaccumulators (Shrift, 1969). Astragalus bisulcatus metabolizes >90% of the accumulated Se into MeSeCys in young shoot tissue. Selenocysteine methyltransferase (SMT), the enzyme responsible for catalyzing the methylation of SeCys to yield MeSeCys, has been cloned from A. bisulcatus (Pickering et al., 2003). In this study, we aimed to investigate selenium accumulation ability of Turkish endemic Astragalus chrysochlorus. For this reason, A. chrysochlorus plants were cultured in Murashige and Skoog medium containing 20–350 M sodium selenate. They were grown normally in all tested concentrations of sodium selenate. Root and stem development of the plants were observed, and dried plant materials were analysed with atomic absorption spectroscopy in the terms of Se accumulation. In addition, SMT gene fragment of A. chrysochlorus were obtained with RT-PCR method and were sequenced. BLAST analysis was shown that the similarity between A. bisulcatus SMT gene and the fragment which we obtained from A. chrysochlorus were similar 95%. References Birringer, M., Pilawa, S., Flohe, L., 2002. Nat. Prod. Rep. 19, 693–718. Berken, A., Mulholland, M.M., LeDuc, D.L., Terry, N., 2002. Crit. Rev. Plant Sci. 21, 567–582. Pickering, I.J., Wright, C., Bubner, B., Ellis, D., Persans, M.W., Yu, E.Y., George, G.N., Prince, R.C., Salt, D.E., 2003. Plant Physiol. 131, 1–8. Reid, M., Duffield-Lillico, A.J., Garland, L., Turnbull, B.W., Clark, L.C., Marshall, J.R., 2002. Cancer Epidemiol. Biomarkers Prev. 11, 1285–1291. Shrift, A., 1969. Annu. Rev. Plant Physiol. 20, 475–495. Whanger, P.D., 2002. J. Am. Coll. Nutr. 21, 223–232.
doi:10.1016/j.jbiotec.2007.07.444 8. Nitrogen removal bioreactor capable of simultaneous nitrification and denitrification applicable to industrial wastewater treatment Masahiko
Morita ∗ ,
Hiroaki Uemoto, Atsushi Watanabe
Central Research Institute of Electric Power Industry (CRIEPI), Abiko, 270-1194 Chiba, Japan Eutrophication, which is caused by excessive nitrogen inflows from domestic and industrial effluents, is a serious environmental problem in closed waters. At present, biological nitrogen removal is mostly carried out through several complicated steps, namely aerobic nitrification, anaerobic denitrification, another
aerobic step to remove surplus electron donor for denitrification, and settling step to segregate activated sludge from wastewater. To simplify the present systems for nitrogen removal, we have investigated a new nitrogen removal bioreactor using packed gel envelopes capable of simultaneous nitrification and denitrification. The envelope consists of two plate polymeric gels with a spacer in between. Ammonia oxidizer, Nitrosomonas europaea and denitrifier, Paracoccus denitrificans are co-immobilized in the plate gels. Ethanol, serving as an electron donor for denitrification, is injected into the internal spaces of envelopes. The immobilized N. europaea oxidizes ammonia to nitrite in the outer surface of envelopes in aerobic contact with wastewater containing ammonia, while the immobilized P. denitrificans reduces the nitrite to nitrogen gas in the inside of envelopes in anaerobic contact with the electron donor. In this way, the packed gel envelopes can remove ammonia from wastewater in a single step. In this research, we investigated large-scale bioreactor (water volume 1.8 m3 ) using actual wastewater discharged from coal-fired thermal power plants. Ammonia-containing actual wastewater that occurred regularly in the thermal power plant was continuously treated using the bioreactor with thirty envelopes for over a year. The bioreactor could remove more than 90% of total nitrogen at hydraulic retention time (HRT) of 24 h. At HRT of 4 h, the bioreactor accomplished a maximum rate (the transformation of NH4 + to N2 ) of 6.0 g N day−1 m−2 of gel surface. The performance was equivalent to that obtained in the laboratory-scale experiments. Furthermore, the bioreactor showed similar nitrogen-removal performances when it treated nitrate-containing wastewater occurring regularly and condensed ammonia-containing wastewater occurring at irregular intervals in the thermal power plants. These results show that the bioreactor can treat various wastewater containing nitrogen and can be applicable to industrial wastewater treatment. Thus, our concept is effective to simplify the large-scale systems for nitrogen removal. doi:10.1016/j.jbiotec.2007.07.445 9. PBDEs bioremediation by microorganisms in wastewater sludges and sediments and monitoring of the toxicity Jana Zl´amal´ıkov´a ∗ , Hana Stiborov´a, Katerina Demnerov´a, Martina Mackov´a, Jana Hajˇslov´a, Jana Pulkrabov´a ICT Prague, Technick´a 3, 16628 Praha 6, Czech Republic During the past several decades heat resistant chemicals have been introduced to reduce the chances of ignition and burning of a wide range of textiles, plastics, building materials, and electronic equipment. To the most applicable belong brominated flame retardants tetrabromobisphenol A (TBBPA), hexabromocyclododecane (HBCD) and polybrominated diphenyl ethers (PBDEs). Many reports describe possibility of PBDEs’ debromination and degradation in anaerobic sediments and wastewater sludges by indigenous bacteria and their consortia.
Abstracts / Journal of Biotechnology 131S (2007) S242–S249
antioxidant selenoproteins, making it an essential micronutrient for animals, microorganisms, and some other eukaryotes (Birringer et al., 2002; Berken et al., 2002). In addition to the basic nutritional requirements for Se, it has become increasingly evident that Se also has potential health benefits. Anticarcinogenic properties of various organic forms of Se against certain types of cancer have been demonstrated (Reid et al., 2002; Whanger, 2002). However, excess Se can be toxic, and the observation that Se bioaccumulation is toxic to wildlife, has generated a surge of interest in phytoremediation of Se. The largest group of Se-hyperaccumulating plants belongs to the genus Astragalus (Fabaceae). Twenty-five species of Astragalus have been characterized as Se hyperaccumulators (Shrift, 1969). Astragalus bisulcatus metabolizes >90% of the accumulated Se into MeSeCys in young shoot tissue. Selenocysteine methyltransferase (SMT), the enzyme responsible for catalyzing the methylation of SeCys to yield MeSeCys, has been cloned from A. bisulcatus (Pickering et al., 2003). In this study, we aimed to investigate selenium accumulation ability of Turkish endemic Astragalus chrysochlorus. For this reason, A. chrysochlorus plants were cultured in Murashige and Skoog medium containing 20–350 M sodium selenate. They were grown normally in all tested concentrations of sodium selenate. Root and stem development of the plants were observed, and dried plant materials were analysed with atomic absorption spectroscopy in the terms of Se accumulation. In addition, SMT gene fragment of A. chrysochlorus were obtained with RT-PCR method and were sequenced. BLAST analysis was shown that the similarity between A. bisulcatus SMT gene and the fragment which we obtained from A. chrysochlorus were similar 95%. References Birringer, M., Pilawa, S., Flohe, L., 2002. Nat. Prod. Rep. 19, 693–718. Berken, A., Mulholland, M.M., LeDuc, D.L., Terry, N., 2002. Crit. Rev. Plant Sci. 21, 567–582. Pickering, I.J., Wright, C., Bubner, B., Ellis, D., Persans, M.W., Yu, E.Y., George, G.N., Prince, R.C., Salt, D.E., 2003. Plant Physiol. 131, 1–8. Reid, M., Duffield-Lillico, A.J., Garland, L., Turnbull, B.W., Clark, L.C., Marshall, J.R., 2002. Cancer Epidemiol. Biomarkers Prev. 11, 1285–1291. Shrift, A., 1969. Annu. Rev. Plant Physiol. 20, 475–495. Whanger, P.D., 2002. J. Am. Coll. Nutr. 21, 223–232.
doi:10.1016/j.jbiotec.2007.07.444 8. Nitrogen removal bioreactor capable of simultaneous nitrification and denitrification applicable to industrial wastewater treatment Masahiko
Morita ∗ ,
Hiroaki Uemoto, Atsushi Watanabe
Central Research Institute of Electric Power Industry (CRIEPI), Abiko, 270-1194 Chiba, Japan Eutrophication, which is caused by excessive nitrogen inflows from domestic and industrial effluents, is a serious environmental problem in closed waters. At present, biological nitrogen removal is mostly carried out through several complicated steps, namely aerobic nitrification, anaerobic denitrification, another
aerobic step to remove surplus electron donor for denitrification, and settling step to segregate activated sludge from wastewater. To simplify the present systems for nitrogen removal, we have investigated a new nitrogen removal bioreactor using packed gel envelopes capable of simultaneous nitrification and denitrification. The envelope consists of two plate polymeric gels with a spacer in between. Ammonia oxidizer, Nitrosomonas europaea and denitrifier, Paracoccus denitrificans are co-immobilized in the plate gels. Ethanol, serving as an electron donor for denitrification, is injected into the internal spaces of envelopes. The immobilized N. europaea oxidizes ammonia to nitrite in the outer surface of envelopes in aerobic contact with wastewater containing ammonia, while the immobilized P. denitrificans reduces the nitrite to nitrogen gas in the inside of envelopes in anaerobic contact with the electron donor. In this way, the packed gel envelopes can remove ammonia from wastewater in a single step. In this research, we investigated large-scale bioreactor (water volume 1.8 m3 ) using actual wastewater discharged from coal-fired thermal power plants. Ammonia-containing actual wastewater that occurred regularly in the thermal power plant was continuously treated using the bioreactor with thirty envelopes for over a year. The bioreactor could remove more than 90% of total nitrogen at hydraulic retention time (HRT) of 24 h. At HRT of 4 h, the bioreactor accomplished a maximum rate (the transformation of NH4 + to N2 ) of 6.0 g N day−1 m−2 of gel surface. The performance was equivalent to that obtained in the laboratory-scale experiments. Furthermore, the bioreactor showed similar nitrogen-removal performances when it treated nitrate-containing wastewater occurring regularly and condensed ammonia-containing wastewater occurring at irregular intervals in the thermal power plants. These results show that the bioreactor can treat various wastewater containing nitrogen and can be applicable to industrial wastewater treatment. Thus, our concept is effective to simplify the large-scale systems for nitrogen removal. doi:10.1016/j.jbiotec.2007.07.445 9. PBDEs bioremediation by microorganisms in wastewater sludges and sediments and monitoring of the toxicity Jana Zl´amal´ıkov´a ∗ , Hana Stiborov´a, Katerina Demnerov´a, Martina Mackov´a, Jana Hajˇslov´a, Jana Pulkrabov´a ICT Prague, Technick´a 3, 16628 Praha 6, Czech Republic During the past several decades heat resistant chemicals have been introduced to reduce the chances of ignition and burning of a wide range of textiles, plastics, building materials, and electronic equipment. To the most applicable belong brominated flame retardants tetrabromobisphenol A (TBBPA), hexabromocyclododecane (HBCD) and polybrominated diphenyl ethers (PBDEs). Many reports describe possibility of PBDEs’ debromination and degradation in anaerobic sediments and wastewater sludges by indigenous bacteria and their consortia.