Work was conducted through six Work Packages (WPs). The project was managed under WP1. In WP2, focused on training and skill development, the fellow participated in various training activities, particularly in the fields of colloid biology and radiochemistry. She gained hands-on experience working with photosynthetic and electroactive microorganisms, inoculating and characterizing them, and evaluating their potential for tritium fractionation. Additionally, she received training in determining tritium activity in liquid (tritiated water) and solid samples (dried biomass) using liquid scintillation analysis. Furthermore, the fellow undertook specialized online training by joining the Tritium School and participated in a short visit to the Leitat Technology Center, which enhanced her expertise in bioelectrochemical processes. She also attended several training workshops on proposal writing, including ERC Starting Grant proposal development, Horizon Europe proposal development, dissemination and open access in Horizon Europe, and project management for European-funded projects. These training sessions strengthened her skills in proposal writing, leading her, as a Principal Investigator, to submit an ERC Starting Grant proposal, two national proposals to the Slovenian Research and Innovation Agency (ARIS), and one proposal under the RSF Innovation Call, programmed by the Jožef Stefan Institute. The fellow also collaborated on two additional proposals submitted to national and international calls. Recently, she successfully secured the prestigious ERC PERSPECTIVE funding to advance novel research at the intersection of semiconductor materials and electroactive microorganisms in bio-photocatalyst hybrids. The Department of Environmental Sciences, being inherently interdisciplinary, encompasses a broad range of research activities as diverse as the environment itself. This unique environment, combined with the fellow's active engagement in multidisciplinary networking, allowed her to collaborate with experts in the field, further strengthening her expertise in environmental sciences. To facilitate knowledge transfer, she collaborated with different research groups where her expertise was needed, such as in the development of bioelectrochemical sensors for methyl mercury detection, engineering biofilms to advance bioelectrochemical systems, and electrodeposition for radionuclide separations. Additionally, she co-mentored a master's student in ecotechnology. In WP3, materials based on TiO2 and BiVO4 were synthesized and characterized to enhance photoelectrochemical (PEC) water-splitting performance. The fellow established a collaboration with the Laboratory for Thin Films at the Ruđer Bošković Institute, focusing on magnetron co-sputtering technique to fabricate heterojunction and doped thin films. The fellow delivered two conference presentations, participated as an invited speaker in one workshop, and has one conference manuscript underway. The results are being prepared for submission to open-access journals in the near future. In WP4, different photosynthetic systems, including cyanobacteria (e.g. Synechococcus elongatus 2973 and Synechococcus leopoliensis 2434) and microalgae (e.g. Chlorella sorokiniana), were inoculated and characterized, and their growth rates in normal and tritiated water were investigated. Moreover, the isotope fractionation capability of photosynthetic systems was analyzed under varying conditions. In WP5, a hybrid bio-photoelectrochemical cell prototype was developed and evaluated for PEC activity. The self-assembly of algae on the surface of BiVO4 and TiO2 was investigated, with findings published in a conference proceeding. Additionally, biofilm was engineered using charged (±) polymers, and its dynamics were studied using fluorescence microscopy. A master's student, co-mentored by the fellow, presented a conference poster on this research.