Mario Javier Gómez-Martínez

The diversity of fungi in different terrestrial and aquatic ecosystems has made it possible to explore their use as important tools in promoting plant growth and in managing plant diseases given their high potential to replace the use of synthetic chemical products (fertilizers and pesticides). Therefore, this review compiles information on the use of filamentous fungi in promoting plant growth, highlighting the most studied fungal genera for this purpose, such as Trichoderma, Penicillum, and Aspergillus. In addition, information is compiled on the promotion of forage grass growth using filamentous fungi, which could be a sustainable and lower-cost alternative in producing pastures to help raise animals.

The present study evaluated the removal efficiency of two dyes, Congo red (CR) and malachite green (MG), using either fresh or dry fungal biomass of two species of Trichoderma (T. virens and T. viride) and activated carbon. After 24 h, the CR removal efficiency obtained with fresh biomass was higher than that obtained with activated carbon. For the MG dye, the average removal with activated carbon (99%) was higher than those obtained with dry and fresh biomass of T. viride and T. virens. Experimental results for fresh and dry fungal biomass showed a good correlation with Langmuir isotherms. The adsorption rates of CR and MG by of T. virens and T. viride can be more appropriately described using the pseudo-second-order rate. We found an adsorption capacity of 81.82 mg g⁻¹ for T. virens with MG dye. Results show that fresh or dry biomass of T. virens can represent a simple and cost-effective alternative for removing industrial dyes such as CR and MG.

The behavior of various filamentous fungi in the presence of metals such as Cu, Zn, Ni, Fe, Mn, and V has been widely reported. However, there is little information regarding metals such as Au, Ag and Pt that are not in the form of nanoparticles. The growth of eight filamentous fungi was evaluated at increasing doses of Au, Ag and Pt. The fungi were reactivated in Petri dishes with potato dextrose agar. Subsequently, individual mycelial disks from each strain were inoculated in PDA plates with the following doses of AuCl₃, Ag₂SO₄ and PtCl₄: 0, 50, 150 and 300 mg L⁻¹, respectively. The plates were then incubated for 20 days—a period in which the diameter of the colony was measured every 24 h. Au showed the highest toxicity for the tested fungi. All silver doses decreased the growth of most of the fungi, while platinum did not cause any inhibitory effect on the growth of the eight tested fungi. With a simple test, it was possible to observe the effect of precious metals (PMs) on the growth of filamentous fungi and consider their possible biotechnological applications in the recovery of PMs from primary or secondary sources.

Most electrical and electronic equipment contain a printed circuit board (PCB), which is the board on which microelectronic components are mounted. The PCBs of obsolete and discarded electrical and electronic equipment are a material of great value due to their high metal content that is of commercial importance (i.e., Au, Ag, Pd, Pt, Ir, Ti, Ge, Si, Al, Cu, Ni, Zn, Fe, Sn, As, and Pb). Hydrometallurgical and pyrometallurgical methods have been used to extract metals from PCBs; however, these methods have energy and environmental disadvantages, which is why in recent years sustainable alternatives have been sought. Among these alternatives are the biological methods that contemplate the use of microorganisms and plants to recover metals from PCBs. In this review, only studies specifying the use of bacteria, fungi, and plants in the recovery of metals from the PCBs of computers and cell phones were considered, since the metallic composition of these plates varies according to the electronic equipment. In addition, the challenges and recommendations for these biotechnological processes to be improved and implemented at the industrial level in the coming years are discussed.

We report the predation on the gecko Hemidactylus angulatus by the spider Ancylometes bogotensis, in the Tropical Dry Forest life zone located at Northern Tolima (Colombia). This short note is a contribution to the knowledge about the natural history of the referenced species because of the potential of A. bogotensis as a biological control agent of geckos that decreases its invasive potential. This is important due to the possibility to make populations of the gecko decline and to restrict the entry of these saurians to natural forested areas.

Hydrometallurgical and pyrometallurgical processes to recover gold (Au) from cell-phone printed circuit boards (PCBs) have the disadvantage of generating corrosive residues and consuming a large amount of energy. Therefore, it is necessary to look for biological processes that have low energy consumption and are friendly to the environment. Among the biological alternatives for the recovery of Au from PCB is the use of cyanogenic bacteria and filamentous fungi in cultures with agitation. Considering that it is important to explore the response of microorganisms in cultures without agitation to reduce energy expenditure in the recovery of metals from PCB, the present investigation evaluated the capacity of Aspergillus niger MXPE6 and a fungal consortium to induce Au bioleaching from PCB in a culture medium with glucose as a carbon source and without agitation (pH 4.5). The results indicate that the treatments with PCB inoculated with the fungal consortium showed a considerable decrease in pH (2.8) in comparison with the treatments inoculated with A. niger MXPE6 (4.0). The fungal consortium showed a significantly higher Au bioleaching (56%) than A. niger MXPE6 (17%). Finally, the use of fungal consortia grown without agitation could be an alternative to recover metals from PCB, saving energy and material resources.

La rana Coquí de las Antillas Eleutherodactylus johnstonei, es considerada una especie invasora de varios países de Centro y Sur América, la cual puede ocasionar efectos negativos al poner en riesgo la salud del hombre, debido a su aguda vocalización tornándose contaminación auditiva y por ser portadora de parásitos. Con el fin de identificar la fuente de introducción y los mecanismos de dispersión de la especie se reporta y se describe la contribución de los viveros comerciales de la ciudad de Ibagué con la llegada de E. johnstonei a la ciudad y de su posterior dispersión a las zonas residenciales por medio del transporte de plantas ornamentales. Individuos de la especie fueron observados en zonas residenciales y comerciales del centro de la ciudad en 2011, 2012 y 2013. Por medio de visitas nocturnas a viveros y recorridos por la ciudad se identificó la presencia de la especie en nueve de los 12 viveros visitados así como también el registro auditivo en siete barrios residenciales de la ciudad. Entrevistas semiestructuradas con viveristas permitieron identificar que la principal zona de donde se surten las plantas de los viveros ibaguereños es el departamento de Cundinamarca específicamente de los municipios de Fusagasugá y Mesitas del Colegio. Se reporta por primera vez a E. johnstonei en la localidad de Chinauta, Fusagasugá (Cundinamarca). Dadas las implicaciones biológicas y los potenciales impactos económicos de la invasión es necesario plantear estrategias de mitigación que conduzcan a controlar la presencia de la especie en los viveros mayoristas y a los de Ibagué para evitar la dispersión a otras zonas de la ciudad y el país.