## 4 Conclusions  
The extensive pollution caused by petroleum, heavy metals, and emerging pathogens represents a growing threat to the ecological balance and health of different habitats. During the recent four decades, the development of bioremediation technologies gained attention as a promising ecological solution for the removal of a wide range of contaminants from polluted environments. The yeast _Y. lipolytica_ is able to produce eco-friendly biocompounds, such as biosurfactants, by degrading petroleum and petroleum compounds (including alkanes), and it is considered as one of the most versatile non-conventional yeast species with a high biotechnological potential. Our study showed that the strain _Y. lipolytica_ CMGB32 has a high ability to assimilate _n_-hexadecane by producing stable biosurfactants. The addition of a crude biosurfactant in synthetic wastewaters contaminated with Pb\({}^{2+}\) and Cd\({}^{2+}\) promoted the growth of natural heavy metal degraders, such as _R. mucilaginousa_, and enhanced their ability to remove heavy metals ions. Also, it positively influenced the physico-chemical parameters of synthetic wastewater and determined the reduction of lead and cadmium ions. Moreover, the concentrated biosurfactants inhibited cell growth and biofilm formation with human pathogenic _C. Krusei_ strains. In conclusion, _Y. lipolytica_ CMGB32 can be considered a promising strain for the further development of biological agents aimed to bioremediate heavy-metal- and emerging pathogen-polluted environments.  
Figure 9: Graphical representation of the inhibitory effect on the adhesion capacity of _C. krusei_ CMGB94 and _C. krusei_ CMGB-Y8 strains treated with different concentrations of the biosurfactant produced by _Y. lipolytica_ CMGB32 (\"_p_ \(<\) 0.05, \"\" \(p\) \(<\) 0.001, \"\" \(p\) \(<\) 0.0001) ([PERSON]’s test).  
**Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app14073048/s1](https://www.mdpi.com/article/10.3390/app14073048/s1)]([https://www.mdpi.com/article/10.3390/app14073048/s1](https://www.mdpi.com/article/10.3390/app14073048/s1)), Figure S1: Emulsification capacity of _Y. lipolytica_ CMGB32 crude biosurfactant against toluene.  
**Author Contributions:** Conceptualization, O.E.C. and V.M.C.; methodology, O.E.C., V.M.C., N.-O.N., E.-M.L. and V.M.; software, V.M.C. and N.-O.N.; validation, O.E.C., V.M.C. and V.M.; formal analysis, O.E.C., V.M.C. and N.-O.N.; investigation, O.E.C., V.M.C., N.-O.N., E.-M.L. and V.M.; resources, O.E.C. and E.-M.L.; data curation, O.E.C.; writing--original draft preparation, O.E.C., V.M.C. and N.-O.N.; writing--review and editing, O.E.C. and V.M.C.; visualization, O.E.C. and V.M.C.; supervision, O.E.C.; project administration, O.E.C., V.M.C. and N.-O.N.; funding acquisition, O.E.C., V.M.C., N.-O.N. and E.-M.L. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was financially supported by the ICUB Senior Grant, contract no. 7423/04.07.2023 financed by the Research Institute of the University of Bucharest and the ICUB Young Research Grant, contract no. 7412/04.07.2023 financed by the Research Institute of the University of Bucharest. N.-O.N. and E.-M.L. also acknowledge the support provided by the Ministry of Research, Innovation and Digitization through contract no. PN 23140201-42N/2023.  
**Institutional Review Board Statement:** Not applicable.  
**Data Availability Statement:** All data are available upon request to the corresponding author. A sample of the biosurfactant is available at the Department of Genetics, Faculty of Biology, University of Bucharest.  
**Conflicts of Interest:** The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.