Aktif Karbonun Lakkaz ile Enzimatik Biyorejenerasyonu

Öz

Aktif karbon, geleneksel biyolojik arıtma sistemlerinde refrakter veya toksik olan organik bileşiklerin arıtımında biyolojik arıtma sistemleriyle kombinasyon halinde yaygın olarak kullanılmaktadır. Bu sistemlerde, aktif karbon üzerinde adsorbe edilen bileşikler, mikroorganizmaların sıvı fazındaki substratları degrede etmesi neticesinde oluşan konsantrasyon gradyanı nedeniyle desorbe olabilir ve daha sonrasında biyolojik olarak parçalanabilir. Bu mekanizmaya aktif karbonun biyorejenerasyonu denir. Önceki çalışmalar, biyorejenerasyon yüzdelerinin konsantrasyon gradyanı kaynaklı desorplanabilirlikten daha yüksek olabileceğini gösterdi. Bu durum bu sistemlerde mikroorganizmalar tarafından salgılanan hücre dışı enzimlerin aktivitesiyle gerçekleşen ekzoenzimatik biyorejenerasyona atfedildi. Bu hücre dışı enzimler, aktif karbon gözeneklerine girerek, daha önce adsorbe edilen bileşiklerle reaksiyona girebilmekte ve bunların karbon yüzeyinden desorpsiyonuna ve degrede olmasına neden olabilmektedir. Ancak literatürde biyorejenerasyon üzerine yapılan çalışmaların hiçbirinde enzimlerin biyorejenerasyon üzerindeki etkisi kesin olarak kanıtlanamamıştır. Çünkü hücre dışı enzimler bu amaçla doğrudan kullanılmamıştır. Bu çalışmada, literatürde fenolik maddelerin oksidasyon reaksiyonlarını katalize ettiği bilinen hücre dışı bir enzim olan ve ticari olarak saf haliyle temin edilebilen lakkaz enzimi kullanılarak aktif karbonun enzimatik biyorejenerasyonu araştırılmıştır. Hedef bileşikler olarak fenol, 2-nitrofenol ve bisfenol-A kullanılmıştır. Bu amaçla termal ve kimyasal olarak active edilmiş iki farklı aktif karbon tipi kullanılarak kesikli adsorpsiyon, abiyotik desorpsiyon, enzimatik biyodegradasyon ve enzimatik biyorejenerasyon deneyleri yapılmıştır. Sonuçlar, aktif karbon tipine bağlı olarak her bir fenolik bileşik için toplam enzimatik biyorejenerasyon verimleri ile abiyotik desorpsiyon verimleri arasında önemli bir fark olduğunu göstermiştir. Böylece literatürde ilk kez ekzoenzimatik biyorejenerasyon niceliksel olarak da gösterilmiştir.

Anahtar Kelimeler

• aktif karbon
• fenol
• 2-nitrofenol
• bisfenol-A
• biorejenerasyon
• lakkaz

Enzymatic Bioregeneration of Activated Carbon by Laccase

Öz

Activated carbon is widely used in combination with biological treatment systems for the treatment of organic compounds, which are refractory or toxic in conventional biological treatment systems. In these systems, compounds adsorbed on activated carbon may desorb within time due to a concentration gradient between adsorbent and the bulk liquid caused by the biodegradation of substrates in the liquid phase by microorganisms. The desorbed compounds are further biodegraded by microorganisms. This mechanism is called bioregeneration of activated carbon. Previous studies showed that bioregeneration percentages could be higher than the concentration gradient-driven desorbability. This was attributed to exoenzymatic bioregeneration occurring due to the activity of extracellular enzymes secreted by microorganisms in these systems. These extracellular enzymes can diffuse into the activated carbon pores where they can react with the previously adsorbed compounds resulting in their desorption from the carbon surface and degradation. However, the effect of extracellular enzymes on bioregeneration was not conclusively proven in any of the literature studies on bioregeneration because extracellular enzymes were not directly used for the purpose of bioregeneration. In this study, enzymatic bioregeneration of activated carbon was investigated by directly using an extracellular enzyme, laccase, which is known from the literature to catalyze the oxidation reactions of phenolic substances and is commercially available in its pure form. Therefore phenol, 2-nitrophenol, and bisphenol-A were used as the target compounds. For this purpose, batch adsorption, abiotic desorption, enzymatic degradation and enzymatic bioregeneration experiments were performed using two different activated carbon types; thermally and chemically activated ones. The results showed that there was a significant difference between the total enzymatic bioregeneration efficiencies and abiotic desorption efficiencies for each phenolic compound depending on the activated carbon type. Thereby, exoenzymatic bioregeneration has been quantitatively shown for the first time in the literature.

Anahtar Kelimeler

• activated carbon
• phenol
• 2-nitrophenol
• bisphenol-A
• bioregeneration
• laccase

Kaynakça

1. Aktaş, O., Çeçen, F. Bioregeneration of activated carbon: a review. Int. Biodeterior. Biodegradation, 59, 257-272. (2007). https://doi.org/10.1016/j.ibiod.2007.01.003
2. Gutkovski, J.P., Schneider, E.E., Michels, C. How effective is biological activated carbon in removing micropollutants? A comprehensive review. J. Environ. Manage., 349, 1-15. (2024). https://doi.org/10.1016/j.jenvman.2023.119434
3. Çeçen, F., Aktaş, Ö. Activated Carbon for Water and Wastewater Treatment: Integration of Adsorption and Biological Treatment. Wiley-VCH Verlag GmbH&Co. KgaA, Weinheim, Germany. (2011). ISBN: 978-3-527-32471-2
4. Aktaş, Ö., Çeçen, F. “Effect of activation type on bioregeneration of various activated carbons loaded with phenol”, Journal of Chemical Technology and Biotechnology, 81, 1081-1092. (2006). https://doi.org/10.1002/jctb.1472.
5. Aktaş, Ö., Çeçen, F. “Cometabolic bioregeneration of activated carbons loaded with 2-chlorophenol”, Bioresource Technology, 100, 4604-4610. (2009). https://doi.org/10.1016/j.biortech.2009.04.053
6. Aktaş, Ö., Çeçen, F. “Adsorption and cometabolic bioregeneration in activated carbon treatment of 2-nitrophenol”, Journal of Hazardous Materials, 177, 956-961. (2010). https://doi.org/10.1016/j.jhazmat.2010.01.011.
7. Chan, P.Y., Lim, P.E., Ng, S.L., Seng, C.E. Bioregeneration of granular activated carbon loaded with phenolic compounds: effects of biological and physico-chemical factors. Int. J. Environ. Sci. Technol.,15, 1699–1712. (2018). https://doi.org/10.1007/s13762-017-1527-4
8. Jain, D.M., Singh, V. Biodegradation of phenolic compounds using immobilized Pseudomonas aeruginosa on granular activated carbon: Effect of immobilization, kinetic study and microbial regeneration. Indian J. Chem. Technol., 28, 402-411. (2021). https://doi.org/10.56042/ijct.v28i4.31179

9. Acevedo, Y.S.M., Mancera, L.T.M., Moreno-Piraján, J.C., Florez M.V. Regeneration of activated carbon by applying the phenolic degrading fungus Scedosporium apiospermum. J. Environ. Chem. Engineer., 8, 1-10. (2020). https://doi.org/10.1016/j.jece.2020.103691
10. Lu, Z., Li, C., Jing, Z., Ao, X., Chen, Z., Sun, W. Implication on selection and replacement of granular activated carbon used in biologically activated carbon filters through meta-omics analysis. Water Res., 198, 1-13. (2021). https://doi.org/10.1016/j.watres.2021.117152
11. Ilyasoglu, G., Vergili, I., Aktas, O., Kaya, Y., Gonder, Z.B., Yilmaz, G. Effect of sludge retention time on bioregeneration of powdered activated carbon loaded with paracetamol. Int. J. Environ. Sci. Technol., 20, 7353-7366. (2023). https://doi.org/10.1007/s13762-023-04861-5
12. Demarche, P., Junghanns, C., Nair, R.R., Agathos, S.N. Harnessing the power of enzymes for environmental stewardship. Biotechnol. Adv., 30, 933-953. (2012). https://doi.org/10.1016/j.biotechadv.2011.05.013
13. Asadgol, Z., Forootanfar, H., Rezai, S., Mahvi, A.H., Faramarzi, M.A. Removal of phenol and bisphenol-A catalyzed by laccase in aqueous solution. J. Environ. Health Sci. Engineer., 12, 93-97. (2014). https://doi.org/10.1186/2052-336X-12-93
14. Escalona, I., de Grooth, J., Font, J., Nijmeijer, K. Removal of BPA by enzyme polymerization using NF membranes. J. Membr. Sci. 468, 192-201. (2014). https://doi.org/10.1016/j.memsci.2014.06.011
15. Otto, B., Schlosser, D. First laccase in green algae: purification and characterization of an extracellular phenol oxidase from Tetracystis aeria, Planta, 240, 1225-1236. (2014). https://doi.org/10.1007/s00425-014-2144-9
16. Uhnakova, B., Petrickova, A., Biedermann, D., Homolka, L., Vejvoda, B., Bendnar, P., Papouskova, B., Sulk, M., Martinkova, L. Biodegradation of brominated aromatics by cultures and laccase of Trametes versicolor. Chemosphere, 76, 826–832. (2009). https://doi.org/10.1016/j.chemosphere.2009.04.016
17. Zhang, J., Liu, X., Xu, Z., Chen, H., Yang, Y. Degradation of chlorophenols catalyzed by laccase. Int. Biodeterior. Biodegradation, 61, 351–356. (2008). https://doi.org/10.1016/J.IBIOD.2007.06.015
18. Arca-Ramos, A., Ammann, E.M., Gasser, C.A., Nastold, P., Eibes, G., Feijoo, G., Lema, J.M., Moreira, M.T., Corvini, P.F.X. Assessing the use of nanoimmobilized laccases to remove micropollutants from wastewater. Environ. Sci. Pollut. Res., 23, 3217-3228. (2016). https://doi.org/10.1007/s11356-015-5564-6
19. Nguyen, L.N., Hai, F.I., Dosseto, A., Richardson, C., Price ,W.E., Nghiem, L.D. Continuous adsorption and biotransformation of micropollutants by GAC-bound laccase in a packed-bed enzyme reactor. Bioresource Technol., 210, 108-116. (2016). https://doi.org/10.1016/j.biortech.2016.01.014
20. APHA-AWWA-WFC, Standard methods for the examination of water and wastewater, 21st ed., Washington, USA. (2005).
21. Hongyan, L., Zexiong, Z., Shiwei, X., He, X., Yinian, Z., Haiyun, L., Zhongsheng, Y. Study on transformation and degradation of bisphenol A by Trametes versicolor laccase and simulation of molecular docking. Chemosphere, 224, 743-750. (2019). https://doi.org/10.1016/j.chemosphere.2019.02.143
22. Smolin, S.K., Vasenko, L.V., Klymenko, N.A., Smolin, Y.S. Desorption of 2-Nitrophenol from Activated Carbon Under the Action of Biotic and Abiotic Factors, J. Water Chem. Tecnol., 41, 158-163. (2019). https://doi.org/10.3103/S1063455X19030044