Assessing three industrially produced fungi for the bioremediation of diclofenac.

Diclofenac is an emerging pollutant: toxic, persistent, and bioaccumulative, present in several environmental niches in a concentration of parts per million. This pharmaceutical's biological removal was reported with various fungal species, showing promissory results. This work aimed at diclofenac removal by individually challenging the fungal species Pleurotus ostreatus, Aspergillus niger, and Penicillium roquefortii but triying to lower the biosorption nature of cell walls by NaCl addition. P. ostreatus removed 100% of the initial diclofenac concentration, whereas A. niger and P. roqueforti removed 74% and 32%, respectively. In all three cases, biosorption by polar interactions was negligible. We demonstrated that stressful environments, such as mineral media, force the fungus to take advantage of its metabolic tools to survive, hence showing higher removal capacity when limiting growth conditions. Bioremediation is an excellent alternative to give residual fungal biomass a secondary use.

Valorization of Parmentiera aculeata juice in growth of probiotics in submerged culture and their postbiotic production: a first approach to healthy foods.

Nowadays, functional foods are greatly accepted by consumers because they improve health and are new sources for substrates to be explored. In this sense, Parmentiera aculeata, a plant distributed in Mexico with beneficial effects on health, has not been chemically explored. In this work, P. aculeata juice was used as carbon source to promote the growth of two probiotic Lactobacillus strains during submerged fermentation. Taguchi's methodology with orthogonal array L9 was applied for culture conditions optimization. pH, agitation, and inoculum concentration variables, each with three levels, were evaluated and the best treatment was validated through a kinetic culture monitoring some postbiotics traits. We observed an increase in 1.76-times in cellular concentration of L. plantarum 14917, and the main produced postbiotics were short-chain fatty acids such as succinic, formic, acetic, propionic, and lactic acids, which are associated with the probiotic metabolism and are important for human health. In the best of our knowledge, this study is the first to describe the valorization of P. aculeata juice as substrate for growth of probiotic strains and future studies are required to gain further applications in functional food production.

Adaptive evolution of Escherichia coli inactivated in the phosphotransferase system operon improves co-utilization of xylose and glucose under anaerobic conditions.

Modification of the phosphoenolpyruvate/sugar phosphotransferase system (PTS) has shown improvement in sugar coassimilation in Escherichia coli production strains. However, in preliminary experiments under anaerobic conditions, E. coli strains with an inactive PTS and carrying pLOI1594, which encodes pyruvate decarboxylase and alcohol dehydrogenase from Zymomonas mobilis, were unable to grow. These PTS⁻ strains were previously evolved under aerobic conditions to grow rapidly in glucose (PTS⁻ Glucose+ phenotype). Thus, in this work, applying a continuous culture strategy under anaerobic conditions, we generate a new set of evolved PTS⁻ Glucose+ mutants, VH30N1 to VH30N6. Contrary to aerobically evolved mutants, strains VH30N2 and VH30N4 carrying pLOI1594 grew in anaerobiosis; also, their growth capacity was restored in a 100%, showing specific growth rates (µ ~ 0.12 h⁻¹) similar to the PTS+ parental strain (µ = 0.11 h⁻¹). In cultures of VH30N2/pLOI1594 and VH30N4/pLOI1594 using a glucose-xylose mixture, xylose was totally consumed and consumption of sugars occurred in a simultaneous manner indicating that catabolic repression is alleviated in these strains. Also, the efficient sugar coassimilation by the evolved strains caused an increment in the ethanol yields.