Biodegradation of the Endocrine-Disrupting Chemical 17α-Ethynylestradiol (EE2) by Rhodococcus zopfii and Pseudomonas putida Encapsulated in Small Bioreactor Platform (SBP) Capsules

Abstract

In this study, we present an innovative new bio-treatment approach for 17α-ethynyestradiol (EE2). Our solution for EE2 decontamination was accomplished by using the SBP (Small Bioreactor Platform) macro-encapsulation method for the encapsulation of two bacterial cultures, Rhodococcus zopfii (R. zopfii ) and Pseudomonas putida F1 (P. putida). Our results show that the encapsulated R. zopffi presented better biodegradation capabilities than P. putida F1. After 24 h of incubation on minimal medium supplemented with EE2 as a sole carbon source, EE2 biodegradation efficacy was 73.8% and 86.5% in the presence of encapsulated P. putida and R. zopfii, respectively. In the presence of additional carbon sources, EE2 biodegradation efficacy was 75% and 56.1% by R. zopfii and P. putida, respectively, indicating that the presence of other viable carbon sources might slightly reduce the EE2 biodegradation efficiency. Nevertheless, in domestic secondary effluents, EE2 biodegradation efficacy was similar to the minimal medium, indicating good adaptation of the encapsulated cultures to sanitary effluents and lack of a significant effect of the presence of other viable carbon sources on the EE2 biodegradation by the two encapsulated cultures. Our findings demonstrate that SBP-encapsulated R. zopfii and P. putida might present a practical treatment for steroidal hormones removal in wastewater treatment processes.

Suitability of Immobilized Systems for Microbiological Degradation of Endocrine Disrupting Compounds

“…The latter is considered to be the strongest among the endocrine factors in the environment [ 10 ]. Synthetic estrogens have been divided into steroidal, such as 17α-ethynylestradiol and 3-methyl ether of ethynylestradiol, used as ingredients of birth control pills, and nonsteroidal estrogens such as diethylstilbestrol used to prevent miscarriages [ 3 , 7 , 11 ]. Human use of the latter was banned in 1972 due to its negative effects, however, it is still used in China as a growth promotor for terrestrial livestock or fish [ 11 ].…”

“…This biological activity can lead to low levels of estrogen in the environment causing endocrine disorders in the wildlife population. Negative effects on development, sex differentiation, reproduction of different animal species and production of vitellogenin have been documented [ 3 , 4 , 7 , 11 , 12 ]. Intersexual disorders in fish in Europe, and a negative impact on the sexual behaviour of frogs in suburban areas in the United States have been observed [ 12 ].…”

“…However, the main problem is the survival of these microorganisms in the complex microbial consortia of wastewater treatment plants [ 5 ]. Hence, more and more attention has been paid to immobilized systems, in which these strains are protected by binding them to a carrier [ 4 , 6 , 7 ]. The use of microorganism immobilization in the drug’s biodegradation not only protects them from harmful environmental conditions, but also leads to an increase in the intensity of the biotransformation processes as a result of the local thickening of the biomass and a higher tolerance of the bacterial cells to these pharmaceuticals [ 4 , 7 ].…”

“…Hence, more and more attention has been paid to immobilized systems, in which these strains are protected by binding them to a carrier [ 4 , 6 , 7 ]. The use of microorganism immobilization in the drug’s biodegradation not only protects them from harmful environmental conditions, but also leads to an increase in the intensity of the biotransformation processes as a result of the local thickening of the biomass and a higher tolerance of the bacterial cells to these pharmaceuticals [ 4 , 7 ]. The intensive development of immobilization methods has led to the discovery of many carriers and immobilization techniques [ 7 , 8 ].…”

“…The use of microorganism immobilization in the drug’s biodegradation not only protects them from harmful environmental conditions, but also leads to an increase in the intensity of the biotransformation processes as a result of the local thickening of the biomass and a higher tolerance of the bacterial cells to these pharmaceuticals [ 4 , 7 ]. The intensive development of immobilization methods has led to the discovery of many carriers and immobilization techniques [ 7 , 8 ]. The new techniques differ in the level of difficulty of the procedure used, cost-effectiveness, efficiency of the processes carried out in the immobilized systems and the usefulness in the immobilization of the microorganisms.…”