María Remedios Mendoza-López

Microbial toxicity tests in the rhizosphere play an important role in the risk assessment and phytoremediation of chemical compounds in the environment. Tests for the inhibition of nodule number (NN), Rhizobia in the rhizosphere (RhR), Rhizobium in nodules (RhN) and arbuscular mycorrhizal fungi (AMFs) are important to evaluate the toxicity as well as the removal of total petroleum hydrocarbons (TPHs), 15 linear alkanes (LAs), and total linear alkanes (TLAs). The inhibition and removal was evaluated at 60 (vegetative stage, VS) and 154 days (reproductive stage, RS) of the life cycle of Crotalaria incana and Crotalaria pallida in soil with four doses of CRO (3, 15, 30, and 45 g/kg) plus a control (16 treatments). Results indicated that RhN and five structures of the AMFs present an index of toxicity (IT < 1), and the microbiological variable is inhibited by the CRO. RhR exhibits a hormesis index (IT > 1) that is stimulated by the CRO in the VS and RS for C. incana and C. pallida. The highest removal of TPHs (77%) was in the rhizosphere of C. incana in the RS with 45 g/kg of CRO. C. pallida removed the greatest amount of TLA (91%). There was a positive correlation between the RhR and the removal of TPHs, TLA, and LAs (higher molecular weight). It could be argued that symbiotic microorganisms are significant for use in toxicity testing, and the rhizosphere of C. incana and C. pallida can be used for the phytoremediation of HTPs and ALs in loamy-clay soil contaminated with CRO.

Currently, there is an increasing demand for plant-based and low-fat snacks. Non-conventional starch and grains are alternative ingredients. Environmentally friendly processing, such as liquid nitrogen and microwaves, can be used to obtain modified starch, as well as hot air frying to cook snacks. The aim of this work was to evaluate the impact of eco-friendly physical modification of starch from Oxalis tuberosa in a low-fat snack processed by hot air frying. First, native starch (NS) was treated with liquid nitrogen (LNS) and liquid nitrogen/microwaves (LNMS), and the amylose/amylopectin content and functional properties were determined. The snacks were formulated with NS or modified starches, amaranth flour, quinoa flour, corn, onion powder, salt, and water; the ingredients were mixed and placed in an electric pasta maker and cooked by hot air frying. The hardness, hedonic test, colorimetric parameters, acrylamide, proximal composition, and fatty acid profile were analyzed. All starches showed similar values of amylose and amylopectin content. LNMS starch had the lowest water solubility index as compared to NS and LNS. The snacks with the starch modified with liquid nitrogen showed the highest values of hardness as well as the highest score for the texture from a hedonic test. The snacks with modified starches showed a lower browning index than the snack formulated with NS. Acrylamide was not detected in any snacks. The lipid value of the snacks with modified starch was 1.9–2.70 g/100 g of sample, providing ω-9, ω-6, and ω-3 fatty acids. All snacks contained 7.7 g of protein/100 g of sample. These low-fat and plant-based snacks are a healthy option made by environmentally friendly technologies.

Lipases are enzymes that catalyze the hydrolysis of carboxylic esters at a lipid–water interface and are able to catalyze reactions such as alcoholysis, esterification, transesterification, and enantioselective synthesis in organic media. They are important biocatalysts for biotechnological and industrial applications—such as in the food and flavor industry—and in the production of biopharmaceuticals, biofuels, biopolymers, and detergents. A desirable property of lipases is stereoselectivity for the production of chemicals with high optical purity. In this work, we report the improvement of the enantioselective capabilities of the Geobacillus thermoleovorans CCR11 lipase. By means of a rational design and bioinformatic approaches, six amino acids of the catalytic cavity of the lipase LipTioCCR11 were substituted resulting in an increase in the optimum temperature of the enzyme and in the resistance to the presence of organic solvents in hydrolytic reactions, and in the promotion of the enantioselective recognition of R isomers of carboxylic acids with importance for the pharmaceutical and food industries.

Este proyecto tuvo como objetivo evaluar la actividad antimicótica de aceites esenciales (AE) de Xkijit (Renealmia alpinia) sobre cultivos de Candida albicans; así como caracterizar el perfil fitoquímico de sus componentes. Para ello se llevó a cabo un estudio in vitro donde se realizó un extracto de AE extraídos de hoja, raíz, tallo y fruto de la planta Xkijit a través del arrastre de vapor, para posteriormente evaluar su actividad antimicótica a diferentes concentraciones sobre placas de crecimiento que contenían C. albicans, durante 24 y 48 horas, a través del método de difusión por disco; así como el perfil fitoquímico de los aceites esenciales por cromatografía de gases acoplada a espectroscopia de masas. Los resultados mostraron que los AE provenientes de hoja, tallo y raíz inhibieron el crecimiento de C. albicans, siendo el AE de raíz el más efectivo, aún en concentraciones bajas. Asimismo, se identificaron 27 componentes bioactivos, donde se identificaron por primera vez monoterpenos y sesquiterpenos que han mostrado potencial antiinflamatorio, antipirético e incluso con actividad repelente contra mosquitos. En conclusión, los AE de Xkijit son una prometedora alternativa terapéutica natural en el diseño de fitofármacos para su uso en tratamiento de diversos padecimientos, incluyendo micosis.