The biopreservation of meat products is of great interest due to the demand for products with low or minimal chemical additives. Lactic acid bacteria (LAB) have been used as protective cultures for many centuries. The objective of this work was to characterize 10 native LAB isolated from meat masses with biopreservative potential for meat products. The isolates were subjected to viability tests with different concentrations of NaCl, nitrite, and nitrate salts, pHs, and temperature conditions. Antibiotic resistance and type of lactic acid isomer were tested. In addition, the isolates were tested against seven pathogens, and inhibitory substances were identified by diffusion in agar wells. Finally, two isolates, Lb. plantarum (SB17) and Lb. sakei (SB3) were tested as protective cultures of chorizo in a model. As a result, the viability at different concentrations of NaCl and nitrate and nitrate salts were obtained. pH and temperature exerted a negative effect on the growth of some of the isolates. Pathogens were inhibited mainly by the presence of organic acids; P. aurius was the most susceptible, and S. typhimurium and S. marcescens were the most resistant. The strains SB17 and SB3 had similar effects on chorizo, and time exerted a deleterious effect on microbiological quality and pH. The results indicated that the 10 isolates show promising characteristics for the preservation of cooked meat products, with the strain Lb. plantarum (SB17) being the most promising.

Las celdas de combustible microbianas (CCM) son una tecnología emergente que aprovecha la degradación de compuestos orgánicos y diferentes sustratos para generar energía, entre los cuales se encuentra el Cr(VI), metal pesado clasificado como tóxico, mutagénico y cancerígeno para los organismos vivos. El propósito de este trabajo fue determinar la actividad electrogénica acoplada a la biorremediación de Cr(VI) con la cepa bacteriana CrLIM26, para lo cual se realizaron ensayos de tolerancia al Cr(VI), por concentración mínima inhibitoria, ensayos de reducción del Cr(VI), identificación filogenética de la cepa bacteriana y se determinó su capacidad de producir energía durante la remoción del Cr(VI) en CCM. La cepa se identificó como Exiguobacterium acetylicum, bacilo corto, Gram positivo, con una tolerancia de 160 mg de Cr(VI) /L, con remoción del 100 % del metal en 11 h, a una concentración de 10 mg de Cr(VI)/L; presentó actividad electrogénica al producir una densidad de potencia de 107.34 y 89.74 µW/m² en medio LB con y sin Cr(VI) respectivamente. Lo anterior permite concluir que la cepa CrLIM26 de E. acetylicum puede ser utilizada para el tratamiento de ambientes contaminados con Cr(VI) en sistemas acoplados a la generación de energías alternativas en CCM simples.

Many tree species are useful for humans and have positive interactions with fauna, however, their germinative traits or seedling establishment are not known. This research aimed to characterize the germination of Schefflera morototoni and Geonoma interrupta seeds and the establishment of their seedlings. Germination tests were carried out in two alternating temperature conditions and the seedlings were tested on two substrates. The results show that seeds recently extracted of these species have high seed moisture content (S. morototoni: 33.8 % and G. interrupta: 32.5 %). The germination percentage of S. morototoni was 93 % and 77 % and G. interrupta was 52 % and 50 %, at 20/30 °C and 25/30 °C, respectively. The establishment of S. morototoni seedlings was 8 % and 4 %, and G. interrupta was 64.4 % and 53.35 %, in silty soil and clay soil, respectively. The average growth of seedlings was lower in S. morototoni (0.8 ± 0.6 mm/week) than in G. interrupta (1.8 ± 0.9 mm/week). It is concluded that the seeds of G. interrupta are dormant and alternating temperatures help to promote seed germination of S. morototoni. Besides, we conclude that the best substrate for the seedling establishment is the silty soil, black and rich in organic matter.