From the beginning of my scientific career, my research has focused on the study of microorganisms, their interactions with each other and with the environment, and how these processes can be harnessed for biotechnological applications. After graduating in Genetics, I began a predoctoral placement at the Carlos III Health Institute, in the Department of Taxonomic Identification, where I received training in bacterial identification using MALDI-TOF mass spectrometry, including sample preparation, spectral analysis and comparison with reference databases. I also gained experience in advanced molecular techniques for the preparation and analysis of genomic libraries using Illumina platforms, from the extraction and quantification of high-quality DNA to genome assembly and annotation with specialised bioinformatic tools.

My research experience began during my undergraduate studies, collaborating with the Environmental Microbial Biotechnology group. In this project, I participated in the development of a biofertiliser based on the identification and characterisation of plant growth-promoting bacterial (PGPB) strains, using methods such as functional activity assays, phytohormone production analyses and antibiotic resistance profiling. The valorisation of plant residues as substrates for bacterial cultivation also involved studies on the optimisation of fermentative processes. In vivo and in vitro bioassays in Lupinus albus and Medicago sativa (forage crops) and in woody species used for reforestation, including holm oak (Quercus ilex) and cork oak (Quercus suber), confirmed its efficacy, leading to a patent on a PGPB strain, the commercialisation of the fertiliser, and promising results both in forage production and in reforestation contexts.

In parallel, I have made progress in the analysis of metagenomic samples from bulk and rhizospheric soils, applying high-throughput sequencing and bioinformatic analyses to characterise microbial communities and assess their impact on soil functionality and plant–microbe interactions. This line of research, which forms the core of my PhD, has enabled me to deepen my expertise in the integration of omics data for the understanding of complex microbial ecosystems, as well as to develop strong skills in scientific writing and publication in specialised journals.

I currently combine my research activity with my position as an adjunct lecturer at the Faculty of Pharmacy, where I teach practical Microbiology sessions in the degree programmes of Medicine, Pharmacy, Nutrition, Dentistry, Genetics and Biotechnology. My teaching approach prioritises the integration of advanced microbiological methodologies, the critical analysis of experimental data, and the application of theoretical concepts in practical contexts. B.1. Breve descripción del Trabajo de Fin de Grado (TFG) y puntuación obtenida The thesis focused on the selection and characterisation of plant growth-promoting bacteria (PGPB) isolated from the rhizosphere of Medicago sativa capable of thriving under adverse conditions, including mercury contamination. A total of 197 strains were evaluated for PGPB activity and metal resistance, and their whole genomes (WGS) were sequenced to confirm their safety by ensuring the absence of virulence factors and transferable antibiotic resistance genes. This process led to the identification of two novel species: Bacillus pretiosus and Pseudomonas agronomica.

The biofertiliser matrices were formulated using an organic residue from the pork-processing industry (EDAR) and an organo-mineral substrate enriched with phosphorus and potassium (ORGA-ON®PK). Their performance was assessed in forage crops (Lupinus albus var. Orden Dorado and Medicago sativa var. Aragón) and in two Mediterranean forest species, Quercus suber and Quercus ilex, in collaboration with the regional agricultural research institute.

Morphometric and compositional analyses evaluated the effects of PGPB formulated in EDAR or ORGA-ON®PK on plant development and forage suitability. In parallel, omics-based approaches were used to study the impact of biofertilisers on rhizospheric microbiota, examining metabolic diversity, community composition and the persistence of inoculated strains. The results showed that Bacillus pretiosus and Pseudomonas agronomica, alone or combined with the organic matrices, improved biomass production and positively influenced microbial community activity and structure. The response of soil microbiota to clinically relevant antibiotics was also assessed through cenoantibiogram analyses.

Overall, the thesis demonstrates the biotechnological potential of newly identified PGPB and valorised organic matrices for agricultural production and reforestation in Mediterranean ecosystems.B.2. Breve descripción del Trabajo de Fin de Máster (TFM) y puntuación obtenida