The global rise in urbanization and industrial activity has led to the production and incorporation of foreign contaminant molecules into ecosystems, distorting them and impacting human and animal health. Physical, chemical, and biological strategies have been adopted to eliminate these contaminants from water bodies under anthropogenic stress. Biotechnological processes involving microorganisms and enzymes have been used for this purpose; specifically, laccases, which are broad spectrum biocatalysts, have been used to degrade several compounds, such as those that can be found in the effluents from industries and hospitals. Laccases have shown high potential in the biotransformation of diverse pollutants using crude enzyme extracts or free enzymes. However, their application in bioremediation and water treatment at a large scale is limited by the complex composition and high salt concentration and pH values of contaminated media that affect protein stability, recovery and recycling. These issues are also associated with operational problems and the necessity of large-scale production of laccase. Hence, more knowledge on the molecular characteristics of water bodies is required to identify and develop new laccases that can be used under complex conditions and to develop novel strategies and processes to achieve their efficient application in treating contaminated water. Recently, stability, efficiency, separation and reuse issues have been overcome by the immobilization of enzymes and development of novel biocatalytic materials. This review provides recent information on laccases from different sources, their structures and biochemical properties, mechanisms of action, and application in the bioremediation and biotransformation of contaminant molecules in water. Moreover, we discuss a series of improvements that have been attempted for better organic solvent tolerance, thermo-tolerance, and operational stability of laccases, as per process requirements.

The aim of this study was to evaluate the effect of oregano essential oil (MOO) from Mexican oregano, Lippia berlandieri Schauer, as substitute for Mexican oregano powder (MOP) on pork chorizo physicochemical characteristics, texture, antioxidant capacity, aerobic bacteria colony counts, and sensory evaluation under storage conditions over 7 d. The treatments were T1 = chorizo + 0.1% MOP and T2 = chorizo + 0.1% MOO. The pH, redness (a*), yellowness (b*), Chroma, and browning index (BI) were affected by treatments and storage time. T2 presented lower pH (5.27) at d 1 than at d 7 (5.34), as well as a* (23.13 vs. 25.27), b* (14.85 vs. 17.45), Chroma (28.60 vs. 30.79), and BI (103.42 vs. 109.82) were higher at d 7. At d 1, hardness (1392.75 vs. 872.29 g), springiness (0.3675 vs. 0.3351 mm), gumminess (491.45 vs. 284.38 g), and chewiness (180.25 vs. 95.43 g mm) were higher in T1 than T2. Aerobic bacteria counts (T1—4.19 vs. 4.73 log CFU/g and T2—4.37 vs. 4.50 log CFU/g, respectively) increased within each treatment at d 7. Antioxidant capacity was not affected (26.48 and 27.42%). Oregano odor was different at 7 d with T2 having a stronger odor (5.70) than T1 with oregano powder (4.63). Mexican oregano essential oil in the pork chorizo formulation improved pH, color parameters, textural profile, and sensory characteristics.

A survey to isolate native white rot basidiomycetes from Northeast Mexico was conducted in the forests of the Sierra Madre Oriental in the state of Nuevo León. A total of 92 isolates from at least 20 different genera, were screened on Bran-Flakes solid plate cultures for the production of ligninolytic oxidases and/or peroxidases with guaiacol and o-anisidine as substrates; their lignin depolymerizing potential using the polymeric dye Poly R 478; their ability to decolorize anthraquinonic (Remazol Brilliant Blue Reactive), azo (Acid Red 44) and triphenylmethane (Crystal Violet) dyes. Among all fungi tested, 15 isolates showed extensive decolorization of the three dyes within a week and gave a positive reaction in guaiacol and o-anisidine tests. Nine of them were also efficient degraders of Poly R-478. Two isolates (CS5 and CU1) showed decolorization of all dyes within 5 days, comparing favorably with reference strains of P. chrysosporium, Pleurotus ostreatus, and Bjerkandera adusta. Decolorization was associated with laccase activity in both isolates and reached 90% or more for all dyes within 24 h in 8-day-old liquid cultures. The coupling of pairs 2,4-dichlorophenol + 4-aminoantipyrine and 3-dimethylaminobenzoic acid + 3-methyl-2-benzothiazolinone hydrazone, strongly suggest that the laccases of both strains correspond to those considered of high redox potential. These strains are considered good candidates for bioremediation of dye polluted effluents due to their ligninolytic potential and decolorizing performance.

Maize is the most important crop around the world and it is highly sensitive to abiotic stress caused by drought, excessive salinity, and extreme temperature. In plants, trehalose has been widely studied for its role in plant adaptation to different abiotic stresses such as drought, high and low temperature, and osmotic stress. Thus, the aim of this work was to clone and characterize at molecular level the trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP) genes from maize and to evaluate its differential expression in maize seedlings under drought stress. To carry out this, resistant and susceptible maize lines were subjected to drought stress during 72 h. Two full-length cDNAs of TPS and one of TPP were cloned and sequenced. Then, TPS and TPP amino acid sequences were aligned with their homologs from different species, showing highly conserved domains and the same catalytic sites. Relative expression of both genes was evaluated by RT-qPCR at different time points. The expression pattern showed significant induction after 0.5 h in resistant lines and after two to four hours in susceptible plants, showing their participation in drought stress response.

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A native strain of Pycnoporus sanguineus (CS2) was selected because of its lignocellulolytic potential on a color-based agar plate screening system; pectinolytic and amylolytic capabilities were also assessed. The effects of different lignocellulosic substrates under submerged cultures of selected fungi on the enzymatic production of cellulases, xylanases, amylases, and laccases were evaluated. Seven different treatments, in which different combinations of wheat straw (WS), wheat bran (WB), orange peels (OP), grapefruit peels (GP), and apple peels (AP) were used, were established. Controls of 2% (w/v) carboxymethyl-cellulose (CMC) and xylan were used in a rich medium for basidiomycetes (RMB). The highest titers were achieved using OP-based cultures, with large titers of CMCases (33.5 U), avicelases (15.7 U), ß-D-glucosidase (72.9U), and xylanases (18.3 U). The best levels of amylase and laccase activity were obtained in the RMB plus CMC (RMB-CMC) (7.2 U) and in the medium OF/AP/GP (6.4 U), respectively. The relative molecular sizes of cellulase, xylanase, and amylase were 66.2, 56.5, and 90.8 kDa, respectively. Laccase and amylase had maximum activities at 60 °C whereas cellulase and hemicellulase had maximum activities at 70 °C. The optimal pH for cellulases, xylanases, and amylases was 5.0 in every case, and more than 95% activity was observed at pH 6. These results reveal some efficient operating parameters for the application of these enzymatic extracts as adjuvants to improve animal nutrition.

The growing global demand for energy and the reduction of energy based on oil are driving the search for new sources of energy that are environmentally friendly. To achieve this goal, it is also necessary to optimize the related processes. In this study, the behavior of the agronomic parameters of, and the energy invested in, production systems based on a new variety of sweet sorghum (Sorghum bicolor (L.) Moench) called ROGER were determined to define the optimal production conditions. To this end, three methods of tillage (minimum, traditional, and traditional tillage with rupture of the plow layer) and three types of fertilizers (inorganic, organic, and without fertilizer) were established, and to estimate the energy efficiency, the inputs and the energy outputs of each system were considered. The traditional tillage with breaking of the plow layer and the organic fertilizer showed the highest values of plant height (2.45 and 2.39 m, respectively); total fresh weight of the plant (51.66 and 50.77 t·ha−1, respectively), of the stem (42.7 and 41.05 t·ha−1, respectively), and of the juice (21.89 and 22.57 t·ha−1, respectively); the volume of the juice (20,783.12 and 22,529.59 L·ha−1, respectively); and Brix degrees (16.04% and 15.01%, respectively). However, the highest energy efficiency was registered in the production system that used the minimum tillage, with a value of 15.11, as well as when no fertilizer was applied with 18.68.

Oregano essential oils from Lippia berlandieri Schauer (Lb) and Poliomintha longiflora Gray (Pl) were tested against the antioxidant butylated hydroxytoluene (Bht) to evaluate effects on the shelf life of ground beef (GB) over 7 days of storage at 4°C. The treatments were GB1 = GB control, GB2 = GB +100 mg/kg of Bht, GB3 = GB +100 mg/kg of Lb, and GB4 = GB +100 mg/kg of Pl. Lightness, redness, hardness, and springiness showed differences (p < .05) between treatments and days interaction, which serve as indicators of ground beef preserved quality and consumer acceptance. Mesophilic, psychrophilic, and lactic acid bacteria numbers and antioxidant activity showed differences (p < .05) for treatments and days. Sensory attributes showed no differences between treatments. The oregano oils may provide extended shelf life for packaged meat products treated with these natural additives and hence may be used for ground beef preservation.