산화환원효소에 의한 휴믹산의 산화중합반응

Oxidative Coupling Reaction of Purified Aldrich Humic Acid by Horseradish Peroxidase

  • 지상현 (경희대학교 토목공학과) ;
  • 김도군 (한국과학기술원 건설및환경공학과) ;
  • 김정현 (경희대학교 토목공학과) ;
  • 고석오 (경희대학교 토목공학과)
  • Jee, Sang-Hyun (Department of Civil Engineering, Kyung Hee University) ;
  • Kim, Do-Gun (Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology) ;
  • Kim, Jeong-Hyun (Department of Civil Engineering, Kyung Hee University) ;
  • Ko, Seok-Oh (Department of Civil Engineering, Kyung Hee University)
  • 투고 : 2010.08.09
  • 심사 : 2010.11.26
  • 발행 : 2010.11.30

초록

휴믹물질의 산화중합반응은 천연 효소나 금속산화물 촉매에 의해 유도될 수 있다. 본 연구에서는 천연 효소인 horseradish peroxidase (HRP)에 의한 휴믹산의 특성 변화와 이러한 변화된 특성이 정밀여과 공정에 미치는 영향을 평가하였다. 정제된 Aldrich 휴믹산(PAHA)이 HRP 및 과산화수소 존재 하에 산화중합되어 보다 크고 복잡한 분자를 형성하였으며, 크기배제크로마토그래피(SEC, size exclusion chromatography, SEC)에서도 평균분자량의 증가가 관찰되었다. 또한, HRP 및 $H_2O_2$ 주입량이 증가함에 따라 PAHA의 분자량은 더욱 증가하였다. 휴믹물질의 화학적 안정성은 산화중합반응에 기인한 휴믹 분자 상호간의 공유결합이 촉진됨에 따라 향상되었으며, 형광 분광 및 적외선 분광 분석 결과, 산화중합반응에 의한 PAHA 분자 작용기의 변화도 확인되었다. 수처리 공정에 미치는 영향을 평가하기 위해, 정밀여과를 적용한 결과, 산화중합반응 산물은 높은 분자량으로 인해 그 제거효율이 크게 향상되었다. 이는 산화중합된 자연유기물이 정밀여과에 의해 제거될 수 있음을 증명하는 것이다.

Oxidative coupling reactions of humic substances (HS) can be catalyzed by a variety of natural extracellular enzymes and metal oxides. In this study, property changes of HS induced by a natural enzyme, horseradish peroxidase (HRP), and the effect of it to microfiltration (MF) were investigated. PAHA was transformed by oxidative coupling reaction with HRP and hydrogen peroxide ($H_2O_2$), verifying the catalytic effects of the HRP. Size exclusion chromatography (SEC) revealed that weight-average molecular weight (MWw) of PAHA was proportionally increased with the dosages of HRP and $H_2O_2$, indicating the transform action of HS into larger and complex molecules. An increase in the conformational stability of HS was achieved through the promotion of intermolecular covalent bondings between heterogeneous humic molecules. Spectroscopic analysis (fluorescence and infrared spectroscopy) proved that functional groups were transformed by the reaction. Additionally, HS and transformed products were undergone microfiltration (MF) to examine the treatment potential of them in a water treatment facility. Original HS could not be removed by MF but larger molecules of transformed products could be removed. Meanwhile, transformed products caused more fouling on the filtration than original HS. This results proved that natural organic matter (NOM) can be removed by MF after its increase in molecular size by oxidative coupling reaction.

키워드

참고문헌

  1. Smejkalova, D., P. Conte and Piccolo, A., "Structural characterization of isomeric dimers from the oxidative oligomerization of catechol with a biomimetic catalyst," Biomacromolecules, 8, 737-743(2007). https://doi.org/10.1021/bm060598o
  2. Bollag, J.-M., "Decontaminating soil with enzymes," Environ. Sci. Technol., 26, 1876-1881(1992). https://doi.org/10.1021/es00034a002
  3. Shindo, H. and Huang, P. M., "Catalytic effects of manganese (IV), iron (III), aluminum, and silicon oxides on the formation of phenolic polymers," Soil Sci. Soc. Am. J., 48, 927-934(1984). https://doi.org/10.2136/sssaj1984.03615995004800040045x
  4. Matocha, C. J., Sparks, D. L., Amonette, J. E. and Kukkadapu, R. K., "Kinetics and mechanism of birnessite reduction by catechol," Soil. Sci. Soc. Am. J., 65, 58-66(2001). https://doi.org/10.2136/sssaj2001.65158x
  5. Huang, Q. and Weber, Jr. W. J., "Peroxidase-catalyzed coupling of phenol in the presence of model inorgarnic and organic solid phases," Environ. Sci. Technol., 38, 5238-5245(2004). https://doi.org/10.1021/es049826h
  6. Kilduff, J. and Weber, Jr. W. J., "Transport and separation of organic macromolecules in ultrafiltration processes," Environ. Sci. Technol., 26, 569-577(1992). https://doi.org/10.1021/es00027a021
  7. Kilduff, J. E., Karanfil, T., Chin, Y-P. and Weber, Jr. W. J., "Adsorption of natural organic polyelectrolytes by activated carbon: a size-exclusion chromatography study," Environ. Sci. Technol., 30, 1336-1343(1996). https://doi.org/10.1021/es950547r
  8. Hur, J. and Schlautman, M. A., "Molecular weight fractionation of humic substances by adsorption onto minerals," J. Colloid Interface Sci., 264, 313-321(2003). https://doi.org/10.1016/S0021-9797(03)00444-2
  9. 허진, 김미경, 박성원, "상류 오염원 추적을 위한 용존 유기물질 Sychronous 형광스펙트럼 분석 연구," 대한환경공학회지, 29(3), 317-324(2007).
  10. Chen, W., P. Westerhoff, J. A. Leenheer and Booksh, K., "Fluorescence citation-emission matrix regional integration to quantify spectra for dissolved organic matter," Environ. Sci. Technol., 37, 5701-5710(2003). https://doi.org/10.1021/es034354c
  11. Zarruk, K. K., Scholer, G. and Dudal, T., "Fluorescence fingerprints and $Cu^{2+}$-complexing ability of individual molecular size fractions in soil-and waste-borne DOM," Chemosphere, 69, 540-548(2007). https://doi.org/10.1016/j.chemosphere.2007.03.039
  12. Huang, Q., Pinto, R. A., Burlingame, D. J., Tang, J. and Weber, Jr. W. J., "Enhanced removal of natural organic matter via peroxidase-mediated oxidative coupling," Water Sci. Technol.; Water Supply, 4(4), 33-40(2004).
  13. Piccolo, A., Cozzolino, A., Conte, P. and Spaccini, R., "Polymerization of humic substances by an enzyme-catalyzed oxidative coupling," Naturwissenschaften, 87, 391-394(2000). https://doi.org/10.1007/s001140050747
  14. Wang, Z., Wu, Z. and Tang, S., "Characterization of dissolved organic matter in a submerged membrane bioreactor by using three-dimensional excitation and emission matrix fluorescence spectroscopy," Water Res., 43, 1533-1540(2009). https://doi.org/10.1016/j.watres.2008.12.033
  15. Uyguner, C. S. and Bekbolet, M., "Evaluation of humic acid photocatalytic degradation by UV-vis and fluorescence spectroscopy," Catal. Today, 101, 267-274(2005). https://doi.org/10.1016/j.cattod.2005.03.011
  16. Stevenson, F. J., Humus chemistry, John Wiley & Sons, Inc., New York(1994).
  17. Wang, M. C. and Huang, P. M., "Ring cleavage and oxidative transformation of pyrogallol catalyzed by Mn, Fe, Al, and Si oxides," Soil Sci., 165(12), 934-942(2000). https://doi.org/10.1097/00010694-200012000-00003
  18. Dec, J., Haider, K. and Bollag, J-M., "Release of substituents from phenolic compounds during oxidative coupling reactions," Chemosphere, 52, 549-556(2003). https://doi.org/10.1016/S0045-6535(03)00236-4
  19. Piccolo, A., Conte, P. and Tagliatesta, P., "Increased conformational rigidity of humic substances by oxidative biomimetic catalysis," Biomacromolecules, 6, 351-358(2005). https://doi.org/10.1021/bm0495203