Antonio Jesús Muñoz

Carbon-based nanostructures acted as potential agents for antibacterial and wound healing properties.

The contamination of natural waters with heavy metals is a global problem. Biosorption is an environmentally friendly and effective technology that offers advantages when metals are present in low concentrations. It also facilitates the recovery and conversion of metals, which are valuable resources. The removal capacity of Ag(I) and Zn(II) ions by Staphylococcus epidermidis CECT 4183 and the ability of its cell extract to synthesize Ag/AgCl and ZnO nanoparticles were investigated. Their biocidal capacity was evaluated. The factors involved were optimized and the mechanisms were studied. The optimal conditions for Ag(I) biosorption were pH 4.5 and a biomass dose of 0.8 g/L. For Zn(II), the biomass dose was 0.2 g/L and pH 4.2. A maximum biosorption capacity (Langmuir model) of 47.43 and 65.08 mg/g, respectively, was obtained. The cell extract promoted the synthesis of Ag/AgCl and ZnO nanoparticles with average sizes below 35 nm. The ZnO nanoparticles exhibited excellent inhibitory properties against planktonic cells of five microbial strains, with MIC values ranging from 62.5 to 250 µg/mL. Their response to biofilms remained between 70% and 100% inhibition at low concentrations (125 µg/mL). The studied bacteria show potential to remove heavy metals and promote the environmentally friendly synthesis of biocidal nanoparticles.

In this study, the capacity of the ubiquitous filamentous fungus Penicillium sp. 8L2 to remove Zn(II) ions present in synthetic solutions was studied and the optimal operating conditions were obtained based on a response surface methodology (RSM). The contact time was optimized through kinetic tests. Equilibrium tests were then carried out, which allowed biosorption isotherms to be obtained for several mathematical models. At the same time, the capacity of the fungal cell extract to transform metal ions into ZnO nanoparticles with a biocidal capacity was evaluated. Its inhibitory capacity for five microbial strains was then determined. The biosorption mechanisms and nanoparticle synthesis were characterized by different crystallographic, spectrophotometric and microscopic analytical techniques. It was confirmed that the metal was bound superficially but also in the periplasmic space with a strong bond to phosphate groups, both in the biosorption stage and during the synthesis and consolidation of the nanoparticles. In addition, the presence of hydroxyl, amino, carbonyl and methylene groups was identified, which could promote the synthesis of nanoparticles, since some of them have a reducing nature. The kinetics showed that the biosorption of Zn(II) occurred in two stages, the first very fast and the second slower. Equilibrium tests identified a maximum biosorption capacity of 52.14 mg/g for the Langmuir model under optimized conditions: a contact time of 5 days, pH 5.6 and a 0.2 g/L biomass dose. The success of the biological synthesis route was confirmed and ZnO nanoparticles with an average size of 18 nm were obtained. The data showed that the nanoparticles showed a good inhibition ability 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.

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

The copper contamination of terrestrial and aquatic ecosystems is a major global environmental problem. Copper is a metal used in many industrial and agricultural processes that is bioaccumulative and highly toxic, making its elimination, recovery and reuse of great interest for environmental sustainability. At the same time, the use of ubiquitous microorganisms is presented as a crucial tool in the field of the sustainability of mineral resources, which in many cases end up as bioaccumulative pollutants, since they can allow the recovery of metallic ions present in low concentrations and, in parallel, the reconversion of these into crystalline species that can be used in other technological fields. The potential of a ubiquitous microorganism, Penicillium sp. 8L2, to retain Cu(II) ions was investigated, as well as the ability of its cellular extract to synthesize CuO nanoparticles, which were subsequently evaluated as biocidal agents against five microorganisms. A response surface methodology was used to determine the optimal operating conditions of the biosorption process, setting the pH at 4.8 and the biomass concentration at 0.8 g/L and obtaining a maximum biosorption capacity at equilibrium of 25.79 mg/g for the Langmuir model. Different analytical techniques were used to study the biosorption mechanisms, which revealed the presence of surface adsorption and intracellular bioaccumulation phenomena involving different functional groups. The fungal cell extract allowed the successful synthesis of CuO-NPs with an average size of 22 nm. The biocidal tests performed with the nanoparticles showed promising values of minimum inhibitory concentrations between 62.5 and 500 µg/mL. Penicillium sp. 8L2 showed good potential for its application in the field of heavy metal bioremediation and for the green synthesis of nanoparticles useful in biomedicine.

Copper contamination of terrestrial and aquatic ecosystems is a major global environmental problem. Copper is a metal used in many industrial and agricultural processes that is bioaccu-mulative and highly toxic, making its elimination, recovery and reuse of great interest for en-vironmental sustainability. The potential of a ubiquitous microorganism, Penicillium sp. 8L2, to retain Cu(II) ions was investigated, as well as the ability of its cellular extract to synthesise CuO nanoparticles, which were subsequently evaluated as biocidal agents against five microorgan-isms. A response surface methodology was used to determine the optimal operating conditions of the biosorption process, setting the pH at 4.8 and the biomass concentration at 0.8 g/L, ob-taining a maximum biosorption capacity at equilibrium of 25.79 mg/g for the Langmuir model. Different analytical techniques were used to study the biosorption mechanisms, which revealed the presence of surface adsorption and intracellular bioaccumulation phenomena involving dif-ferent functional groups. The fungal cell extract allowed the successful synthesis of CuO-NPs with an average size of 22 nm. The biocidal tests performed with the nanoparticles showed promising values of minimum inhibitory concentrations between 62.5 and 500 µg/ml. Penicillium sp. 8L2 showed good potential for its application in the field of heavy metal bioremediation and for the green synthesis of nanoparticles useful in biomedicine.

Copper contamination of natural waters is a global problem that affects ecosystems and public health, yet this metal is an essential micronutrient and has important applications. The efficacy of Staphylococcus epidermidis CECT 4183 as a Cu(II) biosorbent in synthetic solutions and its potential ability to synthesize CuO nanoparticles (CuO-NPs) from its cellular extract was investigated. In addition, the biocidal potential of the nanoparticles was evaluated against five microorganisms. Using response surface methodology, the optimal operating conditions were determined to be biomass dose, 0.2 g/L, and pH 5.5. Equilibrium tests were performed, and biosorption isotherms were obtained for four models with a maximum biosorption capacity of 48.14 mg/g for the Langmuir model. Different spectroscopic and microscopic techniques were used to determine the mechanisms involved in the biosorption process, which was dominated by surface physicochemical interactions with strong involvement of methyl, methylene, carbonyl, amino, and phosphate groups. The techniques also allowed for characterizing the obtained nanoparticles, which had a quasi-spherical morphology and an average size of 14 nm. Finally, biocidal tests showed that the CuO-NPs had a good inhibitory capacity for the microorganisms tested, with minimum inhibitory concentrations (MIC) between 62.5 and 500 µg/mL for bacteria and between 1000 and 2000 µg/mL for yeasts. S. epidermidis CECT 4183 showed good potential for Cu(II) bioremediation and for the synthesis of CuO-NPs with biocidal capacity. S. epidermidis CECT 4183 showed good potential for use in Cu(II) biosorption, and its cell extract presented a high capacity for the green synthesis of CuO-NPs, which at the same time turned out to be good biocidal agents.

Three types of silver/silver chloride nanoparticles were obtained by green synthesis from three types of microbial biomass. Their biocidal capacity was tested against six microorganisms. Two filamentous fungi were used that had previously demonstrated the ability to synthesise nanoparticles, Penicillium sp. 8L2 and Botryosphaeria rhodina MAMB-05. Also, the synthesis capacity of a yeast, Rhodotorula mucilaginosa 1S1, was evaluated. The original protocols underwent slight modifications. At the same time, the fractional inhibitory concentration was obtained. The interaction between specific antibiotics and the nanoparticles that showed the greatest biocidal capacity came from Penicillium sp.8L2, and it was studied further. All nanoparticles were characterised by UV–vis spectrophotometry and transmission electron microscopy (TEM). Also, their size distribution was analysed, which was in the range of 4 to 34 nm. The biocidal capacity of the nanoparticles for a group of bacteria and fungi was studied, presenting very low values in the range of 2.5–10 µg/mL for bacteria and 4–256 µg/mL for fungi. The interactions between the nanoparticles synthesised by Penicillium sp. 8L2 and a group of specific antibiotics for the tested microorganisms were also studied, proving that there was a synergistic interaction with vancomycin and ciprofloxacin and Staphylococcus epidermidis CECT 4183 and Escherichia coli CECT 101 bacteria, respectively. Graphical abstract

The efficiency of Rhodotorula mucilaginosa 1S1 as an Ag(I) biosorbent and at the same time its ability to biosynthesize recoverable silver nanoparticles is evaluated. Kinetic, equilibrium and thermodynamic tests are carried out for 19 °C, 27 °C and 37 °C, from which the process is adjusted to a pseudo second-order kinetics and to the Freundlich model, while optimal operational conditions are determined at 27 °C. The thermodynamic study shows positive values for enthalpy (ΔH: 133.23 kJ/mol) and entropy (ΔS: 0.4976 kJ/(mol K)), while the Gibbs free energy (ΔG) value is 12.136 kJ/mol. For a metal concentration of 459 mg/L, a maximum biosorption capacity (q_m) of 137.2 mg/g at 19 °C is obtained, while for 100 mg/L concentration a q_m value of 60.44 mg/g is obtained at the same temperature. The mechanisms involved in the biosorption process are studied by infrared spectroscopy, X-ray diffraction and scanning and transmission electron microscopy, while the nanoparticle synthesis is evaluated by ultraviolet–visible spectrophotometry (UV-vis) and transmission electron microscopy. The results indicate that the biomass is a good biosorbent and also has the ability to synthesize silver nanoparticles (Ag/AgCl) with sizes between 12 nm and 20 nm.