Biodegradation of the endocrine-disrupting chemical 17α-ethynylestradiol (EE2) by Rhodococcus zopfii and Pseudomonas putida encapsulated in small bioreactor platform (SBP) capsules

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. zopff 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 effcacy 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 effcacy 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 effciency. Nevertheless, in domestic secondary effuents, EE2 biodegradation effcacy was similar to the minimal medium, indicating good adaptation of the encapsulated cultures to sanitary effuents 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.