Antimicrobial Potential of Chitosan Films Incorporated with Alcoholic Extract from Mimosa tenuiflora Leaves.

Antimicrobial films were prepared with chitosan containing the methanolic extract of M. tenuiflora leaves (FECT20%, FECT30%, and FECT40%), and their antimicrobial activities were evaluated by agar diffusion. The films were characterized by IR spectroscopy, scanning electron microscopy (SEM) and TG/DTG curves. TG/DTG curves showed thermal stability of chitosan-extract films up to 166 ºC. Micrographs of chitosan-extract films revealed an increase in porosity with the addition of extract. The FECT40% film showed inhibition zone diameters (IZ) against Micrococcus luteus, Staphylococcus aureus, Bacillus subtilis, and B. cereus, ranging from 1.0 ± 0.02 to 0.72 ± 0.09 cm. Only FECT30% and FECT40% inhibited the P. aeruginosa with IZs of 0.68 ± 0.02 and 0.77 ± 0.06 cm, respectively. In turn, the extract showed inhibition against B. subtilis and B. cereus, with IZs values of 0.92 ± 0.2 cm and 0.72 ± 0.05 cm, respectively. Additionally, the crude extract presented antioxidant potential with inhibition percentages of 32.74% ± 0.90 for ABTS and 27.04% ± 1.36 for DPPH. The antimicrobial and antioxidant activities of the crude extract, as well as the antimicrobial property of chitosan-extract films, suggests the potential of these biopolymers for the development of wound healing bandages and new food packaging alternatives.

A Review about the Mycoremediation of Soil Impacted by War-like Activities: Challenges and Gaps.

(1) Background: The frequency and intensity of war-like activities (war, military training, and shooting ranges) worldwide cause soil pollution by metals, metalloids, explosives, radionuclides, and herbicides. Despite this environmentally worrying scenario, soil decontamination in former war zones almost always involves incineration. Nevertheless, this practice is expensive, and its efficiency is suitable only for organic pollutants. Therefore, treating soils polluted by wars requires efficient and economically viable alternatives. In this sense, this manuscript reviews the status and knowledge gaps of mycoremediation. (2) Methods: The literature review consisted of searches on ScienceDirect and Web of Science for articles (1980 to 2023) on the mycoremediation of soils containing pollutants derived from war-like activities. (3) Results: This review highlighted that mycoremediation has many successful applications for removing all pollutants of war-like activities. However, the mycoremediation of soils in former war zones and those impacted by military training and shooting ranges is still very incipient, with most applications emphasizing explosives. (4) Conclusion: The mycoremediation of soils from conflict zones is an entirely open field of research, and the main challenge is to optimize experimental conditions on a field scale.

Antileshimania, anti-Trypanosoma cruzi and antimicrobial activities of scandenin and 4'-O-methylderrone from Deguelia costata.

Scandenin and 4'-O-methylderrone were isolated from the ethanol extract of the roots and dichloromethane extract of the leaves of Deguelia costata (Benth.) A.M.G. Azevedo & R.A. Camargo, respectively. These compounds and their extracts had their antiprotozoal, antibacterial, antifungal, and cytotoxic activities tested. All samples were active for amastigotes of the T. cruzi, with EC50 values varying from 34.5 to 9.8 µg mL-1. The 4'-O-methylderrone and scandenin showed better leishmanicidal action against the promastigote of L. amazonensis, with EC50 of 43.3 and 45.9 µg mL-1, respectively, when compared to their extracts. All extracts and scandenin showed activities against Staphylococcus sp, Bacillus sp, and Candida sp. The compounds did not show cytotoxicity on rat macrophages. As confirmed by spectroscopic analyses, the extracts are rich in phenolics, mainly isoflavonoids. The study of D. costata is a promising strategy for discovering isoflavones and 4-hydroxy-3-phenylcoumarins with antiprotozoal, antibacterial, and antifungal activities.

An overview of the environmental applicability of vermicompost: from wastewater treatment to the development of sensitive analytical methods.

The use of vermicompost (humified material) for treating wastewaters, remediating polluted soils, improving agricultural productivity, protecting crop production, and developing sensitive analytical methods is reviewed here, covering the past 17 years. The main advantages of vermicompost, considering all applications covered in this paper, comprise (i) easy acquisition, (ii) low costs, (iii) structural, chemical, and biological characteristics responsible for exceptional adsorptive capacities as well as pollutant degradation, and (iv) the promotion of biocontrol. Specifically, for wastewater decontamination, a considerable number of works have verified the adsorption of toxic metals, but the application of vermicompost is still scarce for the retention of organic compounds. Problems related to the final disposal of enriched vermicompost (after treatment steps) are often found, in spite of some successful destinations such as organic fertilizer. For decontaminating soils, the use of vermicompost is quite scarce, mainly for inorganic pollutants. In agricultural productivity and biocontrol, vermicompost imparts remarkable benefits regarding soil aggregation, plant nutrition, and the development of beneficial microorganisms against phytopathogens. Finally, the use of vermicompost in sensitive analytical methods for quantifying toxic metals is the newest application of this adsorbent.

Evaluation of two bioadsorbents for removing paracetamol from aqueous media

The frequent contamination of water resources with drugs comprises one the most important environmental problems. In order to avoid serious disturbances for aquatic life, efficient and economically viable procedures should be developed for removing common pollutants, as paracetamol. From these considerations, the present work evaluated the efficiency of sugar cane bagasse (SCB) and vegetable sponge (VS), two natural adsorbents commonly found in Brazil, for retaining paracetamol molecules dispersed in aqueous solutions. Thus, systems composed of glass columns and peristaltic pumps were optimized and, for pH, the best value was 7.0. After optimisation, adsorption isotherms were built and it was possible to calculate the MAC F values for SCB (120.5 ug/g) and VS (37.5 ug/g). Additionally, real matrices of pretreated water, from a municipal plant for water catchment, were enriched with paracetamol at 5 uM and passed through glass columns packed with SCB, VS and activated carbon (AC). The results showed that SCB was more attractive than AC in terms of price and efficiency (60 percent against 45 percent adsorption, respectively), while VS was responsible for removing 40 percent of paracetamol dissolved in the enriched water samples. Thus, the proposed natural adsorbents can be classified as viable materials to remove paracetamol from water used for human consumption.

Evaluation of sugar-cane bagasse as bioadsorbent in the textile wastewater treatment contaminated with carcinogenic congo red dye

A methodology involving sugar cane bagasse bioadsorbent was developed in order to remove the carcinogenic congo red dye from aqueous medium. The results showed high efficiency with retention of 64 ± 6 percent in synthetic congo red solution and 94 ± 5 percent in effluent enriched with congo red, at 10.0 g of the bioadsorbent. The adsorption system provided a maximum adsorption capacity of 4.43 mg/g. Tests showed independence adsorption properties, when compared with the column flow rates. The treatment units could be operated with flexibility. From the results, it was possible to conclude that sugar cane bagasse could be an adequate bioadsorbent.

Neste trabalho foi desenvolvida uma metodologia de remoção do corante carcinogênico congo red de sistemas aquosos. Os resultados mostraram uma elevada eficiência de remoção sendo de 64 ± 6 por cento para soluções sintéticas de vermelho congo, e 94 ± 5 por cento para efluente industrial enriquecido com vermelho congo utilizando 10 g de bioadsorvente. A capacidade máxima adsotiva encontrada foi de 4,43 mg/g. Os testes de percolação revelaram independência das porcentagens adsortivas em relação às vazões das colunas. Estes resultados indicam viabilidade de uso do bagaço de cana-de-açucar no tratamento de efluentes contendo o congo red.

Removal of Cu, Cr, Ni, Zn, and Cd from electroplating wastes and synthetic solutions by vermicompost of cattle manure.

This study was undertaken to evaluate the retention of Cu, Cr, Ni, Zn, and Cd under laboratory conditions from synthetic solution and electroplating wastes by vermicompost. A glass column was loaded with vermicompost, and metal solutions were passed through it. Metal concentrations were then measured in the eluate in order to evaluate the amounts retained by the vermicompost. Measurements of pH, metal concentrations, moistness, organic matter and ash contents, and infrared and XRD spectroscopy were used for vermicompost characterisation. Vermicompost residues obtained from this process were used for plant nutrition in eroded soil collected from a talus near a highway. Metal retention (in g of metal/kg of vermicompost) from effluents ranged from 2 for Cr and Zn to 4 in the case of Ni. In synthetic solutions, the values for metal retention were 4 for Cd and Zn, 6 for Cu and Ni, and 9 for Cr. The results also showed that metal concentrations in the purified effluents were below the maximum values established for waste discharges into rivers by the Brazilian Environmental Standards. The relatively high available Cd concentration of the vermicompost residue resulted in plant damage. This effect was attributed to the presence of Cd in the synthetic solution passed through the vermicompost. The data obtained do not give a complete picture of using vermicompost in cultivated lands, but such values as are determined do show that it can be suitable to remove heavy metals from industrial effluents.