Wheat bran (WB) is a rich source of phenolic compounds (PCs) with antioxidant capacity (AOX). Approximately 90% of these PCs are bound to the cell wall matrix, which limits their bioavailability. Fermentation with Saccharomyces cerevisiae is an effective strategy to release these bound phenolics. This study aimed to evaluate the effect of fermentation on the release of bound PCs in WB and their AOX during an in vitro digestion system. WB was fermented with Saccharomyces cerevisiae for 2, 4, and 6 days and subsequently subjected to simulated digestion. Free PCs were extracted with methanol, while bound PCs were obtained through alkaline hydrolysis. Total PCs were quantified using the Folin–Ciocalteu method, and AOX was assessed through DPPH, TEAC, and FRAP assays. The content of bound PCs significantly increased after fermentation (p < 0.05): 30.24 ± 0.06 mg GAE/g (day 2), 27.18 ± 0.40 mg GAE/g (day 4), and 28.41 ± 0.40 mg GAE/g (day 6), compared with unfermented WB (7.7 ± 0.21 mg GAE/g) (p < 0.05). AOX was notably enhanced; DPPH reached its peak on day 4 (47.38 ± 0.07 µmol TE/g) (p < 0.05). TEAC was highest on day 2 (26.20 ± 0.43 µmol TE/g) compared with the control (20.14 ± 0.22 µmol TE/g) (p < 0.05) and FRAP showed a slight improvement on day 6 (57.38 ± 0.10 µmol TE/g) relative to the control (56.22 ± 0.13 µmol TE/g) (p < 0.05). Fermentation with Saccharomyces cerevisiae promotes the release of bound PCs in WB and enhances its AOX, highlighting its potential as a functional food ingredient.

La contaminación ambiental por metales pesados es producto en gran medida de las actividades humanas, en particular de la industria minera. La extracción y procesamiento de minerales genera grandes cantidades de compuestos tóxicos que afectan la calidad del medio ambiente y la salud de los seres vivos. Durante mucho tiempo se ha buscado desarrollar estrategias que permitan remover los metales pesados del medio ambiente con el fin de mitigar su toxicidad. Dentro de estas estrategias destacan las que usan organismos, como plantas, hongos, algas y bacterias, ya que estos son más eficientes, no generan residuos secundarios y no son costosas. Sin embargo, los organismos empleados deben tener la capacidad de crecer en altas concentraciones de metales para poder utilizarlos en la remediación. En este trabajo se busca divulgar los diferentes mecanismos que utilizan las bacterias para la remoción de metales, así como los metales que pueden llegar a ser eliminados.

Understanding microbial adaptation and tolerance based on the cellular concentration and biosorption capacity provides critical insights for evaluating microbial performance under heavy metal stress, which is essential for selecting efficient strains or consortia for bioremediation applications. In this study, the adaptation and tolerance of Bacillus megaterium and Rhodotorula mucilaginosa to elevated concentrations of copper (Cu) and manganese (Mn) were investigated by introducing the maximum adaptation concentration (MAC) alongside the maximum tolerable concentration (MTC) and the minimum inhibitory concentration (MIC). A Gaussian model was fitted to the relative growth responses to estimate the MACs, MTCs, and MICs. B. megaterium exhibited MACs of 4.6 ppm Cu and 393.9 ppm Mn, while R. mucilaginosa showed MACs of 59.6 ppm Cu and 64.4 ppm Mn, corresponding to concentrations that stimulated their maximum cell density. A biosorption analysis revealed average capacities of 6.3 ± 5.3 mg Cu/g biomass and 28.6 ± 17.2 mg Mn/g biomass, positively correlated with the MTCs, indicating enhanced metal uptake under sublethal stress. The co-culture assays demonstrated dynamic microbial interactions shaped by the type and concentration of metal, including coexistence, competitive substitution, and dominance by tolerance. These findings support the use of MACs as indicators of growth stimulation and MTCs as thresholds for enhanced metal uptake, providing a dual-parameter framework for selecting metallotolerant microorganisms for metal recovery strategies.

Schematic representation of the sequential SHARON-ANAMMOX process including overall ammonium decrease for each section. Improper discharge of fish processing wastewater (FPW) from fishmeal production, filleting, and washing of raw materials and equipment causes adverse environmental impacts. Biological processes are an alternative to FPW treatment. The SHARON process (Single reactor system for High Activity Ammonia Removal Over Nitrate) can partially transform ammonia to nitrite in aerobic conditions. The SHARON reactor produces an optimal NO2−/NH4+ ratio that can be utilized by an ANAMMOX (ANaerobic AMMonium Oxidation) reactor to produce gaseous nitrogen under anaerobic conditions. This study evaluates a sequential SHARON-ANAMMOX process under saline conditions as an alternative for treating high-nitrogen wastewater. Both reactors operated at neutral pH, 34 °C, and HRT of 1 d, with increments of 4–12 gNaCl/L. The SHARON reactor operated at 250 rpm and 0.7 mgDO/L. The SHARON reactor attained a 50% partial ammonium-to-nitrite conversion and a 1–1.32 NO2−/NH4+ ratio. The ANAMMOX reactor reached 80% efficiency and complete nitrite removal. Results indicate that the sequential SHARON-ANAMMOX process achieved high ammoniacal nitrogen removal efficiency under saline conditions, demonstrating successful adaptation to up to 12 gNaCl/L in both reactors. This study validates the applicability of a sequential SHARON-ANAMMOX process under saline conditions as a sustainable alternative for FPW.