Fatma Özge YILMAZ, Emine ERTEKİN, Ulaş TEZEL

Benzalkonyum klorürlerin Pseudomonas sp. BIOMIG1 tarafından farklı koşullar altında biyotransformasyon kinetiği

Dezenfektan aktif maddeleri kentsel ve endüstriyel atıksularda oldukça sık rastlanan kirleticilerdir. Bu kirleticilerin biyolojik sistemlerde giderimi oldukça zordur. Yüzeysel sularda da sıkça karşılaşılan bu kirleticiler hem doğal hayatı hem de insan sağlığını tehdit etmektedir. Bu çalışmanın amacı, atıksuda en çok karşılaşılan kirleticilerden biri olan benzalkonyum klorürlerin (BAK’ler) biyolojik sistemlerde en verimli şekilde giderimini sağlayacak koşulların belirlenmesidir. Bu amaçla, atıksudan izole edilmiş BAK gideren bir bakteri olan Pseudomanas sp. BIOMIG1’in farklı koşullarda BAK biyotransformasyon kinetiği belirlenmiştir. Elde edilen veriler ve Michaelis-Menten modeli kullanılarak, bu mikroorganizmanın BAK biotransformasyon kinetiği parametreleri hesaplanmış ve uygulanan koşulların kinetiğe etkisi belirlenmiştir. BIOMIG1, BAK’leri 1.4 mg/L-saat hızında giderebilmekte ve bu kirleticileri amonyak ve karbon dioksite dönüştürmektedir. Mililitrede yüz bin adet bakteri yoğunluğu gibi düşük bakteri yoğunluklarında bile BAK gecikmeli de olsa yüksek hızda giderilebilmektedir. BAK homologlarının biyotransformasyon hızı karşılaştırıldığında, 14 karbon alkil zincir uzunluğuna sahip BAK en hızlı, 16 karbonlu BAK ise en yavaş biyotransformasyon hızına sahiptir. BAK giderim hızının en yüksek olduğu sıcaklık 35°, bu sıcaklık üstündeki sıcaklıklarda BIOMIG1 yaşayamamaktadır. Dolayısıyla yüksek sıcaklıklarda BAK parçalanması ya benzildimetilamin birikmesiyle sonlanmış ya da hiç gerçekleşmemiştir. Bu çalışmanın sonuçları, özellikle BAK gibi mikrokirleticilerin arıtımını hedefleyen ileri arıtma sistemlerinin tasarlanması ve işletilmesinde faydalı olacaktır.

Anahtar Kelimeler:

Benzalkonyum klorür, Biyodönüşüm, Kinetik, Modelleme, Pseudomonas sp. BIOMIG1

Biotransformation kinetics of benzalkonium chlorides by Pseudomonas sp. BIOMIG1 under different conditions

Active ingredients of disinfectants are very common pollutants in urban and industrial wastewater. Removal of these contaminants is very difficult in biological treatment systems. As a result; these pollutants, which are also frequently detected in surface waters, threaten both nature and human health. The objective of this study is to determine the optimum conditions that will provide the most efficient removal of benzalkonium chlorides (BACs), a common contaminant, in biological treatment systems. For this purpose, BAC biotransformation kinetics were determined under different conditions using Pseudomanas sp. BIOMIG1, a bacterium that is the key BAC degrader in the environment. Using the data collected and the Michaelis-Menten growth model, BAC biotransformation kinetic parameters were calculated and the effect of the applied conditions on kinetics was determined. BIOMIG1 can transform BACs at a rate of 1.4 mg/L-hour and converts these pollutants into ammonia and carbon dioxide. BAC mineralization can be achieved even at low bacterial densities such as 100000 cells/mL after a short delay. When biotransformation rate of BAC homologs was compared, BAC with 14 carbon alkyl chain length had the fastest and BAC with 16 carbons had the slowest rate of biotransformation. The temperature at which the BAC biotransformation rate was the highest was 35 degrees. BAC was converted to benzyldimethylamine at all temperatures above 35 degrees since BIOMIG1 does not survive above this temperature. The outcomes presented in this study would be used for the design and operation of advanced treatment systems targetting the removal of micropollutants like BACs.

Keywords:

Benzalkonium chloride, Biotransformation, Kinetics, Modeling, Pseudomonas sp. BIOMIG1,

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