## 3 Microbiological Degradation of EDCs
[40] observed that 17\(\beta\)-estradiol was converted to estrone under aerobic conditions, whereas under anaerobic conditions, estrone may undergo interconversion to 17\(\beta\)-estradiol. Fungal degradation usually occurs using extracellular enzymes. They can interact with mycelium-bound enzymes. Moreover, fungi can secrete low molecular weight redox mediators responsible for increasing the degradation potential. The participation of intracellular enzymes in the degradation of microcontaminants was also observed [30]. An example would be the degradation of 17\(\beta\)-estradiol by _Trichoderma citrinoviride_ AJAC3. This fungus secretes ligninolytic enzymes such as manganese peroxidase and lignin peroxidase, which play a significant role in this hormone degradation. In the first stage of degradation, there is a decrease in estrogenic activity due to the conversion of estradiol to estrone. The nature of this reaction is probably radical [22]. During the degradation of EDCs by _Trametes versicolor_, increased lactose activity was observed. The radical mechanism of lactose activity leads to the formation of phenoxy radicals from phenolic EDCs, which undergo nonenzymatic oxidation reactions. Probably, due to the hydrophobic nature of EDCs, intracellular enzymes also participate in their degradation, including the cytochrome P-450 system. The resulting hydroxylated EDCs derivatives can then be metabolized via \(\beta\)-oxidation [30; 58]. Hydroxylated derivatives of progesterone were also observed by [PERSON] et al. [42] and [PERSON] et al. [46] during its biotransformation by _Aspergillus brasiliensis_ and _Circinella muscae_, respectively. It was demonstrated that _Aspergillus nidulans_ VKPM F-1069 hydroxylates progesterone at the position C11\(\alpha\) to 11\(\alpha\)-hydroxyprogesterone. Next, this compound undergoes 6\(\beta\)-hydroxylation or acetylation to 6\(\beta\),11\(\alpha\)-dihydroxyprogesterone and 11\(\alpha\)-acetoxyp progesterone, respectively (Figure 7) [45]. In turn, _Ascomycota_ and _Zygomycota_ filamentous fungi are able to effective hydroxylation at position 7\(\alpha\)-, 7\(\beta\)-, 11\(\alpha\)- and 14\(\alpha\) of 3-oxo-4-ene androstane steroids (Figure 8) [43]. [PERSON] et al. [44] identified intermediates produced during testosterone and 17\(\alpha\)-ethylnylestradiol decomposition by _Lentinual edodes_. On this basis, we have proposed a degradation pathway for 17\(\alpha\)-ethylnylestradiol, shown in Figure 9.  
Little is known about the degradation pathways of mycotoxins and bactericidal compounds with hormonal activity. One of the better described degradation pathways is the decomposition of zeanelenone, a compound that is a serious threat because of its presence in contaminated food. This mycotoxin compound is broken down by cleaving the lactone ring to 1-(3,5-dihydroxyphenyl)-10\({}^{\prime}\)-hydroxy-1-undecen-6\({}^{\prime}\)-one or (5S)-5-((2,4-dihydroxy-6-[(1E)-5-hydroxymethyl-1-en-1-yl]benzoyl)oxy) hexanoic acid. These intermediates do not have estrogenic activity [31]. [PERSON] et al. [59] described the 411-nonylphenol degradation pathway by _Pseudomonas putida_ KT2440. A side chain of 411-nonylphenol is released from the aromatic ring as a dead-end product-3-methyl-3-octanol as a result of ipso-hydroxylation catalysed by monooxygenase. The second intermediate is hydroquinone, which is assimilated by bacterial cells [59]. Figure 6: Testosterone biodegradation by bacteria in anoxic conditions; 2,3-SAOA–17-hydroxy-1-oxo-2,3-seco-androstan-3-oic acid; 2,5-SDAD–17-hydroxy-2,5-seco-3,4-dinorandrost-1,5-dione [57]. Figure 8: Testosterone and its derivatives biotransformation by fungi [43; 44; 46]. Figure 7: Progesteroneo biotransformation by fungi [42; 45; 46]. It appears that the ability of microorganisms to biotransformation EDCs is a universal feature. However, the information presented above shows that only a few microorganisms are capable of completely degrading endocrine compounds. Therefore, it is highly justified to exploit the potential of such strains in purification systems.