Biotechnological Applications of the Ubiquitous Fungus <em>Penicillium</em> sp. 8L2: Biosorption of Zn(II) and Synthesis of ZnO Nanoparticles as Biocidal Agents

The capacity of the ubiquitous filamentous fungus Penicillium sp. 8L2 to remove Zn(II) ions pre-sent in synthetic solutions was studied and the optimal operating conditions were obtained based on a response surface methodology (RSM). The contact time was optimized by kinetic tests. Equilibrium tests were then carried out, which allowed the biosorption isotherms to be obtained for several mathematical models. At the same time, the capacity of the fungal cell ex-tract to transform metal ions into ZnO nanoparticles with biocidal capacity was evaluated. Its inhibitory capacity on five microbial strains was then determined. The biosorption mechanisms and nanoparticle synthesis were characterized by different crystallographic, spectrophotometric and microscopic analytical techniques. The kinetics showed that the biosorption of Zn(II) oc-curred in two stages, the first very fast and the second slower. Equilibrium tests dentified a maximum biosorption capacity of 52.14 mg/g for the Langmuir model under optimized condi-tions: Contact time of 5 days, pH 5.6 and 0.2 g/L biomass dose. The success of the biological syn-thesis route was confirmed and ZnO nanoparticles with an average size of 18 nm were obtained, which showed good inhibition data against the tested microorganisms, with values ranging from 62.5 to 1000 µg/mL. Penicillium sp. 8L2 is a promising ubiquitous microorganism in the field of heavy metal biosorption and applied biotechnology