## 2 Pharmaceuticals and Personal Care Products (PPCPs) in the Ecosystems
### Microbial Remediation in Culture
#### 2.1.4 Mixed Culture  
The complete mineralization of emerging contaminants is achieved while using mixed cultures because the synergistic enzymatic activities of the members of a consortium are often more effective than the individual action of each (Figure 2). However, the response of mixed cultures depend on multiple factors, so if synergistic interactions are not generated, or even if competitive interactions occurred, the results may not be better [151]. Controlled co-cultures have expanded our knowledge. Thus, _Trametes versicolor_ and _Ganoderma lucidum_ were used to remove 13 different pharmaceuticals and generate biodiesel from the generated sludge. Combining both strains increase the removal efficiency as a result of the interactions developed between them [161]. The antibacterial activity of antibiotics could be eliminated after treatments with pure and co-culture of _P. chrysosporium_ and _Pycnoporus sanguineus_[245]. Co-culture of _Acaligenes faecalis_ and _P. sanguineus_ degrade well SMX [246]. _Cunningham_ sp. could be involved in the degradation of endocrine disrupting chemicals by a mixed culture with WRF [247]. The complete mineralization of E2\(\alpha\) by metabolization was achieved by ammonia oxidizing bacteria, together with heterotrophic bacteria [42]. Microbial interactions between _Arthobacter_ sp. and _Pimelobacter_ sp. also allow for the complete mineralization of sulfradiazine. Synergistic effects were observed in mixed cultures of bacteria and fungi that could effectively and completely remove some PPCPs, while neither fungi nor bacteria alone could remove the compound, suggesting that bacteria and fungi can adopt different but complementary metabolic pathways to remove organic compounds [104; 248]. The consortia of cyanobacteria/microalgae and bacteria can be efficient in the detoxification of organic pollutants from wastewaters, as compared to the individual microorganisms. These associations have been frequently used in photoreceptors (see Section 2.3.1). _Chlorella-Aspergillus_ pellets were investigated for the degradation of seven pharmacological compounds. In this lab-test, only one of them was degraded and the presence of algae did not suppose a benefit in the final degradation [249]. One of the troubles associated with the use of microalgae in WWTP is the subsequent collection of them (clarification). Co-pelletization using _T. versicolor_ provided a solution to problems that are associated with current energy-intensive and costly algae harvesting processes [250]. Microalga-duckweed association can completely eliminate estrogens from wastewater mediating processes of sorption and biodegradation [99]. Figure 2 shows the documented biodegradation of E2\(\alpha\) where different types of microorganisms and natural processes can intervene. Hydrophobic bioabsorption [107] and bioaccumulation can derive in PPCPs stabilization within the biomass, white bioabsorption, and biodegradation up to mineralization (CO\({}_{2}\) + H\({}_{2}\)O) can remove completely pollutants from the ecosystem. Fundamentally bacteria [97; 98] and also microalgae [99] usually perform intracellular degradation, whereas fungi metabolize this compound by extracellular degradation that is mediated by laccase. So far, the  
intervention of other lignolithic enzymes has not been described [101]. Intermediate metabolites could be secreted into the medium and biodegraded through a chain of synergistic reactions that are mediated by other microorganisms [39; 42] or bioaccumulated by conjugation and/or accumulation in cellular organelles. Natural adsorbents, such as active carbon, favor the elimination of this hormone [111] and the biosurfactants help with its mobilization and subsequent elimination [105]. Recently, it has been described how photooxidic humic acids (mainly semiquinone radical) not only favor the oxidation of E2\(\alpha\) but can also be used as the last acceptors of electrons in respiration, activating the development of bio-degraders [106; 107].