Biotransformation of 2,4,6-Trinitrotoluene by a cocktail of native laccases from Pycnoporus sanguineus CS43 under oxygenic and non-oxygenic atmospheres.

2,4,6-Trinitrotoluene (TNT) is a highly toxic nitroaromatic explosive known for its environmental consequences, contaminating soil and groundwater throughout its life cycle, from production to disposal. Therefore, the urgency of developing innovative and ecological strategies to remedy the affected areas is recognized. This study reports, for the first time, the enzymatic biotransformation of TNT by a cocktail of native laccases from Pycnoporus sanguineus CS43. The laccases displayed efficient TNT conversion under both oxygenic and non-oxygenic conditions, achieving biotransformation rates of 80% and 87% within 48 h at a temperature of 60 °C and pH 7. Preliminary kinetic constants were calculated with the laccase cocktail, being a Vmax of 1.133 µM min-1 and 0.2984 µM min-1, and the Km values were 1586 µM and 458 µM, in an oxygenic and non-oxygenic atmosphere, respectively. High-performance liquid chromatography-mass spectrometry (HPLC/MS) confirmed the formation of amino dinitrotoluene isomers and hydroxylamine isomers as biotransformation products. In summary, this study suggests the potential application of laccases for the direct biotransformation of recalcitrant compounds like TNT, offering an environmentally friendly approach to address contamination issues.

Effect of light stress on lutein production with associated phosphorus removal from a secondary effluent by the autoflocculating microalgae consortium BR-UANL-01.

Microalgae have become promising microorganisms for generating high-value commercial products and removing pollutants in aquatic systems. This research evaluated the impact of sunlight intensity on intracellular pigment generation and phosphorus removal from secondary effluents by autoflocculating microalgae consortium BR-UANL-01 in photobioreactor culture. Microalgae were grown in a secondary effluent from a wastewater treatment plant, using a combination of low and high light conditions (photon irradiance; 44 µmol m-2 s-1 and ≈ 1270 µmol m-2 s-1, respectively) and 16:8 h light:dark and 24:0 h light:dark (subdivided into 18:6 LED:sunlight) photoperiods. The autoflocculant rate by consortium BR-UANL-01 was not affected by light intensity and achieved 98% in both treatments. Microalgae produced significantly more lutein, (2.91 mg g-1) under low light conditions. Phosphate removal by microalgae resulted above 85% from the secondary effluent, due to the fact that phosphorus is directly associated with metabolic and replication processes and the highest antioxidant activity was obtained in ABTS•+ assay by the biomass under low light condition (51.71% µmol ET g-1). In conclusion, the results showed that the autoflocculating microalgae consortium BR-UANL-01 is capable of synthesizing intracellular lutein, which presents antioxidant activity, using secondary effluents as a growth medium, without losing its autoflocculating activity and assimilating phosphorus.

Recent Advances in Prodigiosin as a Bioactive Compound in Nanocomposite Applications.

Bionanocomposites based on natural bioactive entities have gained importance due to their abundance; renewable and environmentally benign nature; and outstanding properties with applied perspective. Additionally, their formulation with biological molecules with antimicrobial, antioxidant, and anticancer activities has been produced nowadays. The present review details the state of the art and the importance of this pyrrolic compound produced by microorganisms, with interest towards Serratia marcescens, including production strategies at a laboratory level and scale-up to bioreactors. Promising results of its biological activity have been reported to date, and the advances and applications in bionanocomposites are the most recent strategy to potentiate and to obtain new carriers for the transport and controlled release of prodigiosin. Prodigiosin, a bioactive secondary metabolite, produced by Serratia marcescens, is an effective proapoptotic agent against bacterial and fungal strains as well as cancer cell lines. Furthermore, this molecule presents antioxidant activity, which makes it ideal for treating wounds and promoting the general improvement of the immune system. Likewise, some of the characteristics of prodigiosin, such as hydrophobicity, limit its use for medical and biotechnological applications; however, this can be overcome by using it as a component of a bionanocomposite. This review focuses on the chemistry and the structure of the bionanocomposites currently developed using biorenewable resources. Moreover, the work illuminates recent developments in pyrrole-based bionanocomposites, with special insight to its application in the medical area.

Highly hazardous pesticides and related pollutants: Toxicological, regulatory, and analytical aspects.

The pervasive manifestation and toxicological influence of hazardous pesticides pose adverse consequences on various environmental matrices and humans, directly via bioaccumulation or indirectly through the food chain. Due to pesticide residues' continuous presence above permissible levels in multiple forms, much attention has been given to re-evaluating to regulate their usage practices without harming or affecting the environment. However, there are regulations in place banning the use of multiple hazardous pesticides in the environment. Thus, efforts must be made to achieve robust detection and complete mitigation of pesticides, possibly through a combination of new and conventional methods. The complex nature of pesticides helps them to react differently across different environmental matrices. Therefore, highly hazardous pesticides are a risk to human well-being and the environment through enzymatic inhibition and the induction of oxidative stress. Consequently, developing fast, sensitive sensing strategies is essential to detect and quantify multiple pesticides and remove the pesticides present in the specific matrix without creating harmful derivatives. Additionally, the technology should be available worldwide to eliminate pesticide residuals from the environment. There are regulations, in practice, that limit the selling, storage, use of pesticides, and their concentration in the environment, although such regulations must be revised. However, the existing literature lacks regulatory, analytical detection, and mitigation considerations for pesticide remediation. Furthermore, the enforcement of such regulations and strict monitoring of pesticides in developing countries are needed. This review spotlights various analytical detection, regulatory, and mitigation considerations for efficiently removing hazardous pesticides.

A paradigm shift to CO2 sequestration to manage global warming - With the emphasis on developing countries.

Global land use changes that tend to satisfy the food needs of augmenting population is provoking agricultural soils to act as a carbon (C) source rather than sink. Agricultural management practices are crucial to offset the anthropogenic C emission; hence, Carbon sequestration (CS) in agriculture is a viable option for reversing this cycle, but it is based on hypotheses that must be questioned in order to contribute to the development of new agricultural techniques. This review summarizes a global perspective focusing on 5 developing countries (DC) (Bangladesh, Brazil, Argentina, Nigeria and Mexico) because of their importance on global C budget and on the agricultural sector as well as the impact produced by several global practices such as tillage, agroforestry systems, silvopasture, 4p1000 on CO2 sequestration. We also discussed about global policies regarding CS and tools available to measure CS. We found that among all practices agroforestry deemed to be the most promising approach and conversion from pasture to agroforestry will be favorable to both farmers and in changing climate, (e.g., agroforestry systems can generate 725 Euroeq C credit in EU) while some strategies (e.g. no-tillage) supposed to be less promising and over-hyped. In terms of conservative tillage (no-, reduced-, and minimal tillage systems), global and DC's land use increased. However, the impact of no-tillage is ambiguous since the beneficial impact is only limited to top soil (0-10 cm) as opposed to conventional mechanisms. Grasses, cereals and cover crops have higher potential of CS in their soils. While the 4p1000 initiative appears to be successful in certain areas, further research is needed to validate this possible mode of CS. Furthermore, for effective policy design and implementation to obtain more SOC stock, we strongly emphasize to include farmers globally as they are the one and only sustainable driver, hence, government and associated authorities should take initiatives (e.g., stimulus incentives, C credits) to form C market and promote C plantings. Otherwise, policy failure may occur. Moreover, to determine the true effect of these activities or regulations on CS, we must concurrently analyze SOC stock adjustments using models or direct measurements. Above all, SOC is the founding block of sustainable agriculture and inextricably linked with food security. Climate-smart managing of agriculture is very crucial for a massive SOC stock globally especially in DC's.

CO2 biocapture by Scenedesmus sp. grown in industrial wastewater.

Greenhouse gases (GHG) emissions are widely related to climate change, triggering several environmental problems of global concern and producing environmental, social, and economic negative impacts. Therefore, global research seeks to mitigate greenhouse gas emissions. On the other hand, the use of wastes under a circular economy scheme generates subproducts from the range of high to medium-value, representing a way to help sustainable development. Therefore, the use of wastewater as a culture medium to grow microalgae strains that biocapture environmental CO2, is a proposal with high potential to reduce the GHG presence in the environment. In this work, Scenedesmus sp. was cultivated using BG-11 medium and industrial wastewater (IWW) as a culture medium with three different CO2 concentrations, 0.03%, 10%, and 20% to determine their CO2 biocapture potential. Furthermore, the concomitant removal of COD, nitrates, and total phosphorus in wastewater was evaluated. Scenedesmus sp. achieves a biomass concentration of 1.9 g L-1 when is grown in BG-11 medium, 0.69 g L-1 when is grown in a combination of BG-11 medium and 25% of industrial wastewater; both cases with 20% CO2 supplied. The maximum CO2 removal efficiency (8.4%, 446 ± 150 mg CO2 L-1 day-1) was obtained with 10% CO2 supplied and using a combination of BG-11 medium and 50% IWW (T2). Also, the highest removal of COD was reached with a combination of BG-11 medium and T2 with a supply of 20% CO2 (82% of COD removal). Besides, the highest nitrates removal was achieved with a combination of BG-11 medium and 75% IWW (T3) with a supply of 10% CO2 (42% of nitrates removal) and the maximum TP removal was performed with the combination of BG-11 medium and 25% IWW (T1) with a supply of 10% CO2 (67% of TP removal). These results indicate that industrial wastewater can be used as a culture media for microalgae growth and CO2 biocapture can be performed as concomitant processes.

Implementation of kLa-Based Strategy for Scaling Up Porphyridium purpureum (Red Marine Microalga) to Produce High-Value Phycoerythrin, Fatty Acids, and Proteins.

Porphyridium purpureum is a well-known Rhodophyta that recently has attracted enormous attention because of its capacity to produce many high-value metabolites such as the pigment phycoerythrin and several high-value fatty acids. Phycoerythrin is a fluorescent red protein-pigment commercially relevant with antioxidant, antimicrobial activity, and fluorescent properties. The volumetric mass transfer coefficient (kLa) was kept constant within the different scaling-up stages in the present study. This scaling-up strategy was sought to maintain phycoerythrin production and other high-value metabolites by Porphyridium purpureum, using hanging-bag photobioreactors. The kLa was monitored to ensure the appropriate mixing and CO2 diffusion in the entire culture during the scaling process (16, 80, and 400 L). Then, biomass concentration, proteins, fatty acids, carbohydrates, and phycoerythrin were determined in each step of the scaling-up process. The kLa at 16 L reached a level of 0.0052 s-1, while at 80 L, a value of 0.0024 s-1 was achieved. This work result indicated that at 400 L, 1.22 g L-1 of biomass was obtained, and total carbohydrates (117.24 mg L-1), proteins (240.63 mg L-1), and lipids (17.75% DW) were accumulated. Regarding fatty acids production, 46.03% palmitic, 8.03% linoleic, 22.67% arachidonic, and 2.55% eicosapentaenoic acid were identified, principally. The phycoerythrin production was 20.88 mg L-1 with a purity of 2.75, making it viable for food-related applications. The results of these experiments provide insight into the high-scale production of phycoerythrin via the cultivation of P. purpureum in an inexpensive and straightforward culture system.

Exploring current tendencies in techniques and materials for immobilization of laccases - A review.

Nanotechnology has transformed the science behind many biotechnological sectors, and applied bio-catalysis is not the exception. In 2017, the enzyme industry was valued at more than 7 billion USD and projected to 10.5 billion by 2024. The laccase enzyme is an oxidoreductase capable of oxidizing phenolic and non-phenolic compounds that have been considered an essential tool in the fields currently known as white biotechnology and green chemistry. Laccase is one of the most robust biocatalysts due to its wide applications in different environmental processes such as detecting and treating chemical pollutants and dyes and pharmaceutical removal. However, these biocatalytic processes are usually limited by the lack of stability of the enzyme, the half-life time, and the application feasibility at an industrial scale. Physical or chemical approaches have performed different laccase's immobilization methods to improve its catalytic properties and reuse. Emerging technologies have been proven to reduce the manufacturing process cost and increase application feasibility while looking for ecological and economical materials that can be used as support. Therefore, this review discusses the trends of enzyme immobilization recently studied, analyzing biomaterials and agro-industrial waste used for that intention, their advantages, and disadvantages. Finally, the work also highlights the performance obtained with these materials and current challenges and potential alternatives.

Phyco-remediation of swine wastewater as a sustainable model based on circular economy.

Pork production has expanded in the world in recent years. This growth has caused a significant increase in waste from this industry, especially of wastewater. Although there has been an increase in wastewater treatment, there is a lack of useful technologies for the treatment of wastewater from the pork industry. Swine farms generate high amounts of organic pollution, with large amounts of nitrogen and phosphorus with final destination into water bodies. Sadly, little attention has been devoted to animal wastes, which are currently treated in simple systems, such as stabilization ponds or just discharged to the environment without previous treatment. This uncontrolled release of swine wastewater is a major cause of eutrophication processes. Among the possible treatments, phyco-remediation seems to be a sustainable and environmentally friendly option of removing compounds from wastewater such as nitrogen, phosphorus, and some metal ions. Several studies have demonstrated the feasibility of treating swine wastewater using different microalgae species. Nevertheless, the practicability of applying this procedure at pilot-scale has not been explored before as an integrated process. This work presents an overview of the technological applications of microalgae for the treatment of wastewater from swine farms and the by-products (pigments, polysaccharides, lipids, proteins) and services of commercial interest (biodiesel, biohydrogen, bioelectricity, biogas) generated during this process. Furthermore, the environmental benefits while applying microalgae technologies are discussed.

Antidepressant drugs as emerging contaminants: Occurrence in urban and non-urban waters and analytical methods for their detection.

Antidepressants are drugs with a direct action on the brain's biochemistry through their interaction with the neurotransmitters, such as dopamine, norepinephrine, and serotonin. The increasing worldwide contamination from these drugs may be witnessed through their increasing presence in the urban water cycle. Furthermore, their occurrence has been detected in non-urban water, such as rivers and oceans. Some endemic aquatic animals, such as certain fish and mollusks, have bioaccumulated different antidepressant drugs in their tissues. This problem will increase in the years to come because the present COVID-19 pandemic has increased the general worldwide occurrence of depression and anxiety, triggering the consumption of antidepressants and, consequently, their presence in the environment. This work provides information on the occurrence of the most administrated antidepressants in urban waters, wastewater treatment plants, rivers, and oceans. Furthermore, it provides an overview of the analytical approaches currently used to detect each antidepressant presented. Finally, the ecotoxicological effect of antidepressants on several in vivo models are listed. Considering the information provided in this review, there is an urgent need to test the presence of antidepressant members of the MAOI and TCA groups. Furthermore, incorporating new degradation/immobilization technologies in WWTPs will be useful to stop the increasing occurrence of these drugs in the environment.

Influence of Low Salt Concentration on Growth Behavior and General Biomass Composition in Lyngbya purpurem (Cyanobacteria).

Cyanobacteria are essential for the vast number of compounds they produce and the possible applications in the pharmaceutical, cosmetical, and food industries. As Lyngbya species' characterization is limited in the literature, we characterize this cyanobacterium's growth and biomass. L. purpureum was grown and analyzed under different salinities, culture media, and incubation times to determine the best conditions that favor its cell growth and the general production of proteins, carbohydrates, lipids, and some pigments as phycocyanin and chlorophyll a. In this study, each analyzed biomolecule's highest content was proteins 431.69 mg g-1, carbohydrates 301.45 mg g-1, lipids 131.5 mg g-1, chlorophyll a 4.09 mg g-1, and phycocyanin 40.4 mg g-1. These results can provide a general context of the possible uses that can be given to biomass and give an opening to investigate possible biocompounds or bio metabolites that can be obtained from it.

Functional Attributes and Anticancer Potentialities of Chico (Pachycereus Weberi) and Jiotilla (Escontria Chiotilla) Fruits Extract.

Mexico has a great diversity of cacti, however, many of their fruits have not been studied in greater depth. Several bioactive compounds available in cacti juices extract have demonstrated nutraceutical properties. Two cactus species are interesting for their biologically active pigments, which are chico (Pachycereus weberi (J. M. Coult.) Backeb)) and jiotilla (Escontria chiotilla (Weber) Rose)). Hence, the goal of this work was to evaluate the bioactive compounds, i.e., betalains, total phenolic, vitamin C, antioxidant, and mineral content in the extract of the above-mentioned P. weberi and E. chiotilla. Then, clarified extracts were evaluated for their antioxidant activity and cytotoxicity (cancer cell lines) potentialities. Based on the obtained results, Chico fruit extract was found to be a good source of vitamin C (27.19 ± 1.95 mg L-Ascorbic acid/100 g fresh sample). Moreover, chico extract resulted in a high concentration of micronutrients, i.e., potassium (517.75 ± 16.78 mg/100 g) and zinc (2.46 ± 0.65 mg/100 g). On the other hand, Jiotilla has a high content of biologically active pigment, i.e., betaxanthins (4.17 ± 0.35 mg/g dry sample). The antioxidant activities of clarified extracts of chico and jiotilla were 80.01 ± 5.10 and 280.88 ± 7.62 mg/100 g fresh sample (DPPH method), respectively. From the cytotoxicity perspective against cancer cell lines, i.e., CaCo-2, MCF-7, HepG2, and PC-3, the clarified extracts of chico showed cytotoxicity (%cell viability) in CaCo-2 (49.7 ± 0.01%) and MCF-7 (45.56 ± 0.05%). A normal fibroblast cell line (NIH/3T3) was used, as a control, for comparison purposes. While jiotilla extract had cytotoxicity against HepG2 (47.31 ± 0.03%) and PC-3 (53.65 ± 0.04%). These results demonstrated that Chico and jiotilla are excellent resources of biologically active constituents with nutraceuticals potentialities.

Evaluation and Predictive Modeling of Removal Condition for Bioadsorption of Indigo Blue Dye by Spirulina platensis.

Among the different chemical and physical treatments used to remove the color of the textile effluents, bioremediation offers many benefits to the environment. In this study, we determined the potential of Spirulina platensis (S. platensis) for decolorizing indigo blue dye under different incubation conditions. The microalgae were incubated at different pH (from 4 to 10) to calibrate for the optimal discoloration condition; a pH of 4 was found to be optimal. The biomass concentration in all experiments was 1 g/L, which was able to decolorize the indigo blue dye by day 3. These results showed that S. platensis is capable of removing indigo blue dye at low biomass. However, this was dependent on the treatment conditions, where temperature played the most crucial role. Two theoretical adsorption models, namely (1) a first-order model equation and (2) a second-order rate equation, were compared with observed adsorption vs. time curves for different initial concentrations (from 25 to 100 mg/L). The comparison between models showed similar accuracy and agreement with the experimental values. The observed adsorption isotherms for three temperatures (30, 40, and 50 °C) were plotted, showing fairly linear behavior in the measured range. The adsorption equilibrium isotherms were estimated, providing an initial description of the dye removal capacity of S. platensis.

Accumulation of PHA in the Microalgae Scenedesmus sp. under Nutrient-Deficient Conditions.

Traditional plastics have undoubted utility and convenience for everyday life; but when they are derived from petroleum and are non-biodegradable, they contribute to two major crises today's world is facing: fossil resources depletion and environmental degradation. Polyhydroxyalkanoates are a promising alternative to replace them, being biodegradable and suitable for a wide variety of applications. This biopolymer accumulates as energy and carbon storage material in various microorganisms, including microalgae. This study investigated the influence of glucose, N, P, Fe, and salinity over the production of polyhydroxyalkanoate (PHA) by Scenedesmus sp., a freshwater microalga strain not previously explored for this purpose. To assess the effect of the variables, a fractional Taguchi experimental design involving 16 experimental runs was planned and executed. Biopolymer was obtained in all the experiments in a wide range of concentrations (0.83-29.92%, w/w DW), and identified as polyhydroxybutyrate (PHB) by FTIR analysis. The statistical analysis of the response was carried out using Minitab 16, where phosphorus, glucose, and iron were identified as significant factors, together with the P-Fe and glucose-N interactions. The presence of other relevant macromolecules was also quantified. Doing this, this work contributes to the understanding of the critical factors that control PHA production and present Scenedesmus sp. as a promising species to produce bio-resources in commercial systems.

Dissimilatory reduction of Fe(III) by a novel Serratia marcescens strain with special insight into the influence of prodigiosin.

A novel pigmented bacterium, initially identified as 11E, was isolated from a site historically known to have various iron-related ores. Phylogenetic analysis of this bacterial strain showed that it belongs to Serratia marcescens. This pigmented S. marcescens 11E cultured individually with glucose, acetate, and glycerol as electron donors along with the soluble electron acceptor iron (Fe) (III) citrate offered a large reduction extent (45.3 %, 31.4 %, and 13.5 %, respectively). On the other hand, when iron oxide (Fe2O3) is used as electron acceptor, the pigmented strain produced a null reduction extent. Surprisingly, the absence of prodigiosin on the bacterial surface (non-pigmented strain) resulted in a large reduction extent of the non-soluble iron form (20-49%). All these extents were comparable and, in some cases, superior to those presented in the literature. Additionally, in the present study, it was found that anthraquinone sulfonate (AQS) stimulated Fe(III) reduction of soluble and non-soluble Fe species only with pigmented S. marcescens. In contrast, in the culture media with the non-pigmented strain, the presence of AQS did not stimulate the Fe(III) reduction. These results suggest that the pigmented phenotype of S. marcescens 11E may perform non-soluble Fe(III) reduction by electron shuttling. In contrast, for the non-pigmented phenotype of this bacterium, non-soluble Fe(III) reduction seems to proceed by direct contact. Our study demonstrates that this bacterium may be used in bioreduction process of heavy metals or as a biocatalyst in bioelectrochemical devices.

Light Intensity and Nitrogen Concentration Impact on the Biomass and Phycoerythrin Production by Porphyridium purpureum.

Several factors have the potential to influence microalgae growth. In the present study, nitrogen concentration and light intensity were evaluated in order to obtain high biomass production and high phycoerythrin accumulation from Porphyridium purpureum. The range of nitrogen concentrations evaluated in the culture medium was 0.075-0.450 g L-1 and light intensities ranged between 30 and 100 µmol m-2 s-1. Surprisingly, low nitrogen concentration and high light intensity resulted in high biomass yield and phycoerythrin accumulation. Thus, the best biomass productivity (0.386 g L-1 d-1) and biomass yield (5.403 g L-1) were achieved with NaNO3 at 0.075 g L-1 and 100 µmol m-2 s-1. In addition, phycoerythrin production was improved to obtain a concentration of 14.66 mg L-1 (2.71 mg g-1 of phycoerythrin over dry weight). The results of the present study indicate that it is possible to significantly improve biomass and pigment production in Porphyridium purpureum by limiting nitrogen concentration and light intensity.