Combining anaerobic digestion slurry and different biochars to develop a biochar-based slow-release NPK fertilizer.

In this research, we developed a biochar-based fertilizer using biogas slurry and biochar derived from lignocellulosic agro-residues. Biogas slurry was obtained through the anaerobic digestion of the organic fraction of municipal solid waste (fresh vegetable biomass and/or prepared food), while biochars were derived from residues from quinoa, maize, rice, and sugarcane. The biochar-based fertilizers were prepared using an impregnation process, where the biogas slurry was mixed with each of the raw biochars. Subsequently, we characterized the N, P and K concentrations of the obtained biochar-based fertilizers. Additionally, we analyzed their surface properties using SEM/EDS and FTIR and conducted a slow-release test on these biochar-based fertilizers to assess their capability to gradually release nutrients. Lastly, a bioassay using cucumber plants was conducted to determine the N, P, and K bioavailability. Our findings revealed a significant correlation (r > 0.67) between the atomic O/C ratio, H/C ratio, cation exchange capacity, surface area, and the base cations concentration with N, P, and/or K adsorption on biochar. These properties, in turn, were linked to the capability of the biochar-based fertilizer to release nutrients in a controlled manner. The biochar-based fertilizer derived from corn residues showed <15 % release of N, P and K at 24 h. Utilization of these biochar-based fertilizers had a positive impact on the mineral nutrition of cucumber plants, resulting in an average increase of 61 % in N, 32 % in P, and 19 % in K concentrations. Our results underscore the potential of biochar-based fertilizers in controlled nutrient release and enhanced plant nutrition. Integration of biochar and biogas slurry offers a promising and sustainable approach for NPK recovery and fertilizer production in agriculture. This study presents an innovative and sustainable approach combining the use of biochar for NPK recovery from biogas slurry and its use as a biochar-based fertilizer in agriculture.

Efecto in vitro de diferentes concentraciones de Allium sativum “ajo” frente a dermatofitos y Candida albicans / In vitro effect of different concentrations of Allium sativum garlic on dermatophytes and Candida albicans

El presente trabajo estuvo orientado a investigar sí Allium sativum ajo en su forma liofilizada posee efecto antimicótico in vitro sobre dermatofitos y Candida albicans. Para ello se trabajó con 100 g. de A. sativum y cultivos de dermatofitos y C. albicans aislados de pacientes con micosis en piel, uñas y cabellos. Se emplearon un total de 30 cultivos puros de los cuales 07 correspondieron a Trichphyton mentagrophytes, 04 a T. rubrum, 04 a Microsporum canis y 15 a C. albicans, los cuales fueron sembrados en Agar Sabouraud e incubados en el caso de dermatofitos por 2 a 3 semanas a temperatura ambiental (20 ± 3ºC) y para C. albicans a 37ºC por 48 a 72 horas. Las pruebas biológicas in vitro incluyeron: la preparación del inóculo de A. sativum y preparación del Diflucan como control. Las pruebas de sensibilidad se realizaron usando el método de difusión en agar (MDA) y el método de dilución en tubo. Según los análisis estadísticos, los resultados indican que para el caso de dermatofitos por el MDA se logra inhibición entre 300 a 400 ug de ajo liofilizado, una concentración mínima inhibitoria (MCI) de 500 ug/mL y un efecto fungicida de 1000 ug/mL. En el caso de C. albicans por el MDA se obtuvo un mayor diámetro de inhibición entre 4000 a 5000 ug, una MCI de 2500 ug/mL y un efecto fungicida de 5000 ug/mL. Estos resultados podrán ser utilizados en la realización de estudios in vivo que corroboren las propiedades medicinales que se le atribuyen al ajo.

The present work attempted to determine if Allium sativum garlic in its form liofilizated has in vitro antimycotic effect on dermatophytes and Candida albicans. We used 100 g. of A. sativum, cultures of dermatophytes and C. albicans isolated of patients with mycosis in skin, fingernails and hair. A total of 30 pure cultures of which 07 of Trichophyton mentagrophytes, 04 of T. rubrum, 04 of M. canis and 15 of C. albicans, which were cultured in Sabouraud Agar. Dermatophytes were incubated for 2-3 weeks under conditions of air temperature (20 ± 3ºC), meanwhile C. albicans was incubated for 48 -72 hours at 37ºC. The in vitro biological tests included: inoculum preparation of A. sativum liofilizated and preparation of Diflucan (control). The tests of sensibility were made using the agar diffusion method and the tube dilution test. According to variance analysis, the results indicate that inhibition determined by the agar diffusion method in dermatophytes was among 300 to 400 ug from liofilizated garlic, also found a minimum inhibitory concentration (MIC) of 500 ug/mL and a fungicidal action of 1000 ug/mL. In the case of C. albicans, it showed bigger inhibition diameter among 4000 to 5000 ug, a minimum inhibitory concentration of 2500 ug/mL and fungicidal action of 5000 ug/mL. These results can be used for in vivo studies in order to confirm the medicinal properties of garlic.