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El artículo que se presenta tiene como propósito fundamental la propuesta de un programa de extensión forestal dirigido al restablecimiento de la especie Byrsonima crassifolia en la Comunidad Peralejo, del municipio Bayamo, provincia Granma. El programa se desarrolló durante los meses de septiembre de 2019 a marzo de 2020, en tres etapas fundamentales: diagnóstico, diseño y ejecución del programa de extensión forestal, y por último su valoración. En el proceso se utilizaron técnicas y métodos de la investigación científica (teóricos y empíricos) que garantizaron la obtención de resultados cualitativamente superiores, tanto para la comunidad como para el rescate de la especie. La información obtenida con la aplicación de diferentes instrumentos se procesó a través del paquete estadístico SPSS versión 21 para Windows. Los principales resultados arrojan la pertinencia de la investigación a partir de la significación histórica de la especie que contrasta con el alto nivel de desconocimiento que poseen al respecto los decisores en el área.

El trabajo se realizó con el objetivo de caracterizar la vegetación de un sector del bosque protector de agua y suelo del río Yara, Municipio Bartolomé Masó, Provincia Granma. Se realizó un inventario florístico donde se levantaron 12 transectos de 100 m² (5 m x 20m) con un área total de 1 200 m2 (0,12 ha), distribuidas sistemáticamente en ambos lados del río. Se identificaron todas las especies que presentaban diámetro mayor de 7 cm de d1.30 m. midiéndose su diámetro y altura, y contándose por estratos el número de individuos por especie, se determinó la estructura vertical, y horizontal del bosque, así como el Índice de Valor de Importancia Ecológico. En la totalidad del patrimonio muestreado se registraron 557 individuos de 52 especies y 47 géneros pertenecientes a 33 familias botánicas. Las familias de mayor riqueza de especie en el área estudiada fueron Leguminosae, Rutaceae, Euphorbiaceae, Sapindaceae, Salicaceae, Sapotaceae y Boraginaceae. Las especies arbóreas mejor representadas en el fragmento de bosque y mayor Índice de Valor de Importancia fueron Guasuma Tomentosa, Roystonea regia, Sterculia apetala y Cedrela odorata.

Copyright of Innovación Tecnológica is the property of Instituto de Informacion Cientifica y Tecnologica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Innovación Tecnológica is the property of Instituto de Informacion Cientifica y Tecnologica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We consider some effects of the change in the molecular properties of the MeOH, EtOH and 1-ProOH due to the presence of a polar solvent, through analysis of the potential of Lennard-Jones between two molecules of these alcohol, in in the middle solvent and emptiness. The comparison of the graphs and the values of the depth of the well of the potential, shows that the centers of mass of molecules of solute are close but when the effects produced by molecules of the means consider that surround them (solvent), in addition the depth to the well of the potential increases when it considers these effects that when they are in the emptiness. The previous study showed the great utility and the possibility of making studies of simple and complex molecular systems with the computacionales tools available in our means. [ABSTRACT FROM AUTHOR]

Pablo Antonio Maia de Farias,1,3 Fernando Gomes Figueredo,2,3 Aline Maria Brito Lucas,3 Rafael Barbosa de Moura,3 Henrique Douglas Melo Coutinho,2 Tania Maria Sarmento da Silva,4 Ana Luiza de Aguiar Rocha Martin,2,3 Marta Maria de França Fonteles1 1Development and Technological Innovation in Medicines, Universidade Federal do Ceará – UFC, Fortaleza-CE, 2College of Biomedicine, Faculdade Leão Sampaio-FLS, 3College of Pharmacy, Faculdade de Medicina Estácio de Juazeiro do Norte-Estácio, Juazeiro do Norte-CE, 4Department of Molecular Sciences, Universidade Federal Rural de Pernambuco, Recife, PE, Brazil Background: The search for new active compounds from the Brazilian flora has intensified in recent years, especially for new drugs with antibiotic potential. Accordingly, the aim of this study was to determine whether riachin has antibiotic activity in itself or is able to modulate the activity of conventional antibiotics.Methods: A non-cyanogenic cyanoglycoside known as riachin was isolated from Bauhinia pentandra, and was tested alone and in combination with three antibiotics (clindamycin, amikacin, and gentamicin) against multiresistant bacterial strains (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus).Results: Riachin did not show significant antibiotic activity when tested alone against any strain (P>0.05). However, when combined with conventional antibiotics, it showed drug-modifying activity against strains of S. aureus exposed to clindamycin (P

Para evaluar el crecimiento de especies arbóreas, establecidas como cortinas rompevientos, y su efecto en el área de pastoreo protegida, se desarrolló una investigación durante dos años en el Campus de la Universidad Federal de Minas Gerais. La cortina rompevientos estuvo conformada por dos franjas con dos hileras de árboles. En la primera, se colocó leucaena (Leucaena leucocephala), y en la segunda acacia mangio (Acacia mangium). Los indicadores estudiados fueron: altura de la planta, diámetro del tallo, diámetro de copa y supervivencia. Las muestras se tomaron mensualmente en 100 % de las plantas utilizadas. Además, se midió el efecto en la humedad del suelo y en la velocidad del viento en el área de pasto protegida, a diferentes distancias de la cortina. Las especies arbóreas evaluadas lograron establecerse y mostraron diferentes hábitos de crecimiento. Leucaena solo logró 2 m de altura, después de un año del transplante, mientras que el crecimiento de acacia fue mucho más rápido, alcanzando una altura superior a 1.50 m, a los 120 d después del trasplante. En todos los muestreos realizados, la humedad del suelo en el área protegida fue siempre similar hasta los 180 m después de la cortina. La velocidad del viento, a 100 cm del suelo, fue superior en todos los momentos, y mostró igual comportamiento que a los 30 cm de altura, lo que indicó el inicio del efecto beneficioso de la cortina en la velocidad del viento. Los resultados mostraron que las especies arbustivas evaluadas presentaron características de crecimiento diferentes y favorables, que permiten su utilización en la formación de cortinas rompevientos en áreas de pastoreo, como otra alternativa de uso de estas especies en sistemas silvopastoriles. [ABSTRACT FROM AUTHOR]

This paper presents an innovative application of chitosan material to be used as pH-responsive valves for the precise control of lateral flow in microfluidic paper-based analytical devices (μPADs). The fabrication of μPADs involved wax printing, while pH-responsive valves were created using a solution of chitosan in acetic acid. The valve-forming solution was applied, and ready when dry; by exposure to acidic solutions, the valve opens. Remarkably, the valves exhibited excellent compatibility with alkaline, neutral, and acidic solutions with a pH higher than 4. The valve opening process had no impact on the flow rate and colorimetric analysis. The potential of chitosan valves used for flow control was demonstrated for μPADs employed for nitrate determination. Valves were used to increase the conversion time of nitrate to nitrite, which was further analyzed using the Griess reaction. The μPAD showed a linear response in the concentration range of 10-100 μmol L -1 , with a detection limit of 5.4 μmol L -1 . As a proof of concept, the assay was successfully applied to detect nitrate levels in water samples from artificial lakes of recreational parks. For analyses that require controlled kinetics and involve multiple sequential steps, the use of chitosan pH-responsive valves in μPADs is extremely valuable. This breakthrough holds great potential for the development of simple and high-impact microfluidic platforms that can cater to a wide range of analytical chemistry applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

3D printing has revolutionized the manufacturing process of microanalytical devices by enabling the automated production of customized objects. This technology promises to become a fundamental tool, accelerating investigations in critical areas of health, food, and environmental sciences. This microfabrication technology can be easily disseminated among users to produce further and provide analytical data to an interconnected network towards the Internet of Things, as 3D printers enable automated, reproducible, low-cost, and easy fabrication of microanalytical devices in a single step. New functional materials are being investigated for one-step fabrication of highly complex 3D printed parts using photocurable resins. However, they are not yet widely used to fabricate microfluidic devices. This is likely the critical step towards easy and automated fabrication of sophisticated, complex, and functional 3D-printed microchips. Accordingly, this review covers recent advances in the development of 3D-printed microfluidic devices for point-of-care (POC) or bioanalytical applications such as nucleic acid amplification assays, immunoassays, cell and biomarker analysis and organs-on-a-chip. Finally, we discuss the future implications of this technology and highlight the challenges in researching and developing appropriate materials and manufacturing techniques to enable the production of 3D-printed microfluidic analytical devices in a single step., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Whisky adulteration is a prevalent practice driven by the high cost of these beverages. Counterfeiters commonly dilute whisky with less expensive alcoholic beverages, water, food additives, drugs or pharmaceuticals. Paracetamol (PAR), an analgesic drug that mitigates hangovers and headaches, is commonly used to adulterate whisky. Currently, the primary method for quantifying PAR levels is high-performance liquid chromatography, but this technique is both time consuming and usually generates more residues. In this context, the utilization of miniaturized and portable analytical devices becomes imperative for conducting point-of-care/need analyses. These devices offer several advantages, including portability, user-friendliness, low cost, and minimal material wastage. This study proposes the selective distance-based PAR quantification on whisky samples using a paper-based microfluidic analytical device (μPAD). Colorimetric detection on paper-based platforms offers great benefits such as affordability, portability, and the ability to detect PAR without complicated instrumentation. The optimal detection conditions were achieved by introducing 5 μL of a mixture containing 7.5 mmol L -1 of Fe(III) and K 3 [Fe(CN) 6 ] into the detection zone, along with 12 μL of whisky samples into the sample zone. The method exhibited linear behavior within the concentration range from 15 to 120 mg L -1 , with a determination coefficient of 0.998. PAR was quantified in adulterated samples. The results obtained with the paper-based devices were compared with a referenced method, and no significant differences were observed at a confidence level of 95%. The μPAD allowed to determine ca. 1 drop of pharmaceutical medicine PAR of 200 mg mL -1 in 1 L of solution, demonstrating excellent sensitivity. This method offers cost-effective and rapid analysis, reducing the consumption of samples, reagents, and wastes. Consequently, it could be considered a viable and portable alternative for analyzing beverages at criminal scenes, customs, and police operations, thereby enhancing the field of forensics.

Microplastics are a major modern challenge that must be addressed to protect the environment, particularly the marine environment. Microplastics, defined as particles ≤5 mm, are ubiquitous in the environment. Their small size for a relatively large surface area, high persistence and easy distribution in water, soil and air require the development of new analytical methods to monitor their presence. At present, the availability of analytical techniques that are easy to use, automated, inexpensive and based on new approaches to improve detection remains an open challenge. This review aims to outline the evolution and novelties of classical and advanced methods, in particular the recently reported electroanalytical detectors, methods and devices. Among all the studies reviewed here, we highlight the great advantages of electroanalytical tools over spectroscopic and thermal analysis, especially for the rapid and accurate detection of microplastics in the sub-micron range. Finally, the challenges faced in the development of automated analytical methods are discussed, highlighting recent trends in artificial intelligence (AI) in microplastics analysis.

This paper describes the design and construction of dual microfluidic paper-based analytical devices (dual-μPADs) as a lab-on-paper platform involving a "do-it-yourself" fabrication protocol. The device comprises a colorimetric and electrochemical module to obtain a dual-mode signal readout sensing strategy. A 3D pen polymeric resin was used to prepare graphite carbon-based electrodes and hydrophobic barriers on paper substrates. The proposed carbon-based ink was employed to manufacture electrodes on paper based on a stencil-printing approach, which were further characterized by electrochemical and morphological analyses. The analytical performance of the dual-μPADs was simultaneously evaluated for lactate, pH, nitrite, and salivary amylase (sAA) analysis. To demonstrate the proof-of-concept, saliva samples collected from both healthy individuals and those with periodontitis were successfully tested to demonstrate the feasibility of the proposed devices. Samples collected from individuals previously diagnosed with periodontitis showed high levels of nitrite and sAA (> 94 μmol L -1 and > 610 U mL -1 ) in comparison with healthy individuals (≤ 16 μmol L -1 and 545 U mL -1 ). Moreover, periodontitis saliva resulted in acid solution and almost null lactate levels. Notably, this protocol supplies a simple way to manufacture dual-μPADs, a versatile platform for sensitive detecting of biomarkers in saliva playing a crucial role towards the point-of-care diagnosis of periodontal disease., (© 2023. Springer-Verlag GmbH Germany, part of Springer Nature.)

Inorganic phosphorous (as phosphate (PO 4 3- ), is one of the essential nutrients for all living forms, either terrestrial or marine. In oligotrophic seawaters, this macronutrient is limited (10 -9  M) and its ratio with other elements (nitrogen or carbon) is denoting the health state of the marine environment; a small variation of its concentration can produce eutrophication. The gold standard method used for PO 4 3- detection is based on colorimetric detection of phosphomolybdate. The colored complex is obtained by mixing water-soluble molybdenum salts (Mo(VI)) and reducing agents in acid media, along with the sample containing PO 4 3- . Moreover, the kinetic of complex formation is slow, about 1 h is generally required for color to develop, exposing the assay to the drawbacks of interferences as those from silica. The detection is preferably performed in a controlled environment (i.e. in a laboratory) because several chemicals and steps of preparations are required as well as the optical instrumentation is not intended for in-field use. Electrochemical sensors offer portability and simplicity making them a practical option for on-site detection applications. To gain an analytical alternative in measuring low quantities of PO 4 3- (10 -9  M), and overcome some of the drawbacks of the classical approaches, we optimised a new easy way to produce a plastic electrode decorated with an alkyl Mo-polyoxometalate (Mo 8 O 26 4- ), that is soluble in organic solvents. This tetra-butyl-ammonium octamolybdate powder, [N (C4H9)4]4 Mo8O26, purposely synthetized was identified with FTIR, Raman, MS methods, and the electroactivity and reactivity with PO 4 3- was confirmed in solution with cyclic voltammetry (CV). When the Mo-decorated electrode was in contact with PO 4 3- , an electroactive phosphomolybdate aggregate formed at the electrode surface that was electrochemically detectable with square wave voltammetry (SWV). A remarkably low detection limit of 6.1 nM, to PO 4 3- , as well as good stability and selectivity were obtained also in real samples. In fact, PO 4 3- was measured in saline simulated and real seawater samples at nM concentrations in less than 5 min. The present investigation provides a new alternative to the current standard colorimetric methods to detect low phosphate concentrations, showing the potential to be used for monitoring nutrients in oligotrophic seawater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgments., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Rapid diagnosis by using small, simple, and portable devices could represent one of the best strategies to limit the damage and contain the spread of viral, bacterial or protozoa diseases, principally when they can be transmitted by air and are highly contagious, as some respiratory viruses are. The presence of antibodies in blood or serum samples is not the best option for deciding when a person must be quarantined to stop transmission of disease, given that cured patients have antibodies, so the best diagnosis methods rely on the use of nucleic acid amplification procedures. Here we present a very simple device and detection principle, based on paper discs coupled to contactless conductivity (C4D) sensors, can provide fast and easy diagnostics that are needed when an epidemic outbreak develops. The paper device presented here solves one of the main drawbacks that nucleic acid amplification tests have when they are performed outside of central laboratories. As the device is sealed before amplification and integrally disposed in this way, amplimers release cannot occur, allowing repetitive testing in the physician's practice, ambulances, or other places that are not prepared to avoid cross-contamination of new samples. The use of very low volume samples allows efficient reagent use and the development of low cost, simple, and disposable point-of-care diagnostic systems., Competing Interests: The authors have declared that no competing interests exist.

Three of the primary bottlenecks, which should be consider for practical, point-of-need use of microbial fuel cell (MFC) analytical devices were surpassed in this work: i) the use of a diffusive barrier, hence, an electrogenic biofilm; ii) longer enrichment/stabilization times to produce a biofilm, made in a laboratory environment, over the electrode; and iii) difficulty comparing results obtained from MFCs based on electrogenic biofilms with standardized bioassays, a setback to be adopted as a new method. Here we show an easy way to determine water toxicity employing planktonic bacteria as biorecognition agents. The paper-based MFC contain an electron carrier (or mediator) to facilitate charge transfer from bacteria to the anode. In this way, there is no need to use biofilms. As far as we know this is the first paper-based MFC containing P. putida KT2440, a well characterized non-pathogenic bacteria previously used in standardized water toxicity bioassays. Results were obtained in 80 min and an effective concentration 50 of 9.02 mg L -1 , calculated for Zn 2+ (a reference toxic agent), was successfully compared with previously published and ISO standardized bioassays, showing a promising future for this technology. The practical design and cost (less than one U.S. dollar) of the paper-based MFC toxicity test presented will open new market possibilities for rapid and easy-to-use MFC analytical devices., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Microbial fuel cells (MFCs) can evolve in a viable technology if environmentally sound materials are developed and became available at low cost for these devices. This is especially important not only for the designing of large wastewater treatment systems, but also for the fabrication of low-cost, single-use devices. In this work we synthesized membranes by a simple procedure involving easily-biodegradable and economic materials such as poly (vinyl alcohol) (PVA), chitosan (CS) and the composite PVA:CS. Membranes were chemical and physically characterized and compared to Nafion®. Performance was studied using the membrane as separator in a typical H-Type MFCs showing that PVA:CS membrane outperform Nafion® 4 times (power production) while being 75 times more economic. We found that performance in MFC depends over interactions among several membrane characteristics such as oxygen permeability and ion conductivity. Moreover, we design a paper-based micro-scale MFC, which was used as a toxicity assay using 16 μL samples containing formaldehyde as a model toxicant. The PVA:CS membrane presented here can offer low environmental impact and become a very interesting option for point of need single-use analytical devices, especially in low-income countries where burning is used as disposal method, and toxic fluoride fumes (from Nafion®) can be released to the environment., Competing Interests: The authors have declared that no competing interests exist.

This study describes for the first time the development of 3D printed microfluidic devices with integrated electrodes for label-free counting of E. coli cells incorporated inside droplets based on capacitively coupled contactless conductivity detection (C 4 D). Microfluidic devices were fully fabricated by 3D printing in the T-junction shape containing two channels for disperse and continuous phases and two sensing electrodes for C 4 D measurements. The disperse phase containing E. coli K12 cells and the continuous phase containing oil and 1% Span ® 80 were pumped through flow rates fixed at 5 and 60 μL min -1 , respectively. The droplets with incorporated cells were monitored in the C 4 D system applying a 500-kHz sinusoidal wave with 1 V pp amplitude. The generated droplets exhibited a spherical shape with average diameter of 321 ± 9 μm and presented volume of 17.3 ± 0.5 nL. The proposed approach demonstrated ability to detect E. coli cells in the concentration range between 86.5 and 8650 CFU droplet -1 . The number of cells per droplet was quantified through the plate counting method and revealed a good agreement with the Poisson distribution. The limit of detection achieved for counting E. coli cells was 63.66 CFU droplet -1 . The label-free counting method has offered instrumental simplicity, low cost, high sensitivity and compatibility to be integrated on single microfluidic platforms entirely fabricated by 3D printing, thus opening new possibilities of applications in microbiology., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The present study was aimed to test an electrochemical sensing approach for the detection of an active chemolithotrophic metabolism (and therefore the presence of chemolithotrophic microorganisms) by using the corrosion of pyrite by Acidithiobacillus ferrooxidans as a model. Different electrochemical techniques were combined with adhesion studies and scanning electron microscopy (SEM). The experiments were performed in presence or absence of A. ferrooxidans and without or with ferrous iron in the culture medium (0 and 0.5 g L -1 , respectively). Electrochemical parameters were in agreement with voltammetric studies and SEM showing that it is possible to distinguish between an abiotically-induced corrosion process (AIC) and a microbiologically-induced corrosion process (MIC). The results show that our approach not only allows the detection of chemolithotrophic activity of A. ferrooxidans but also can characterize the corrosion process. This may have different kind of applications, from those related to biomining to life searching missions in other planetary bodies., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Context Melissa officinalis subsp. inodora Bornm. (Lamiaceae) has been used since ancient times in folk medicine against various diseases, but it has not been investigated against protozoa. Objective To evaluate the activities of M. officinalis against Leishmania braziliensis, Leishmania infantum and Trypanosoma cruzi as well as its cytotoxicity in fibroblast cell line. Materials and methods The fresh leaves were chopped into 1 cm(2) pieces, washed and macerated with 99.9% of ethanol for 72 h at room temperature. Antiparasitic activity of M. officinalis was accessed by direct counting of cells after serial dilution, while the cytotoxicity of M. officinalis was evaluated in fibroblast cell line (NCTC929) by measuring the reduction of resazurin. The test duration was 24 h. High-performance liquid chromatography (HPLC) was used to characterise the extract. Results The extract at concentrations of 250 and 125 μg/mL inhibited 80.39 and 54.27% of promastigote (LC50  value = 105.78 μg/mL) form of L. infantum, 80.59 and 68.61% of L. brasiliensis (LC50 value  = 110.69 μg/mL) and against epimastigote (LC50 value  = 245.23 μg/mL) forms of T. cruzi with an inhibition of 54.45 and 22.26%, respectively, was observed. The maximum toxicity was noted at 500 μg/mL with 95.41% (LC50  value = 141.01 μg/mL). The HPLC analysis identified caffeic acid and rutin as the major compounds. Discussion The inhibition of the parasites is considered clinically relevant (< 500 μg/mL). Rutin and caffeic acids may be responsible for the antiprotozoal effect of the extract. Conclusion The ethanol extract of M. officinalis can be considered a potential alternative source of natural products with antileishmania and antitrypanosoma activities.

Spheres, tubes, and planar-shaped nanomaterials as Fe3O4 nanoparticles (MNPs), multiwalled carbon nanotubes (MWCNT), and graphene oxide (GO) were used for the first time to treat microfluidic paper-based analytical devices (μPADs) and create a biocompatible layer with high catalytic surface. Once glucose measurements are critical for diabetes or glycosuria detection and monitoring, the analytical performance of the proposed devices was studied by using bienzymatic colorimetric detection of this carbohydrate. The limit of detection values achieved for glucose with μPADs treated with MNPs, MWCNT, and GO were 43, 62, and 18 μM, respectively. The paper surface modification solves problems associated with the lack of homogeneity on color measurements that compromise the sensitivity and detectability levels in clinical diagnosis.

Microbial fuel cells (MFCs) are bioelectrochemical systems (BES) capable of harvesting electrons from redox reactions involved in metabolism. In a previous work, we used chemoorganoheterotrophic microorganisms from the three domains of life-Bacteria, Archaea, and Eukarya-to demonstrate that these BES could be applied to the in situ detection of extraterrestrial life. Since metabolism can be considered a common signature of life "as we know it," we extended in this study the ability to use MFCs as sensors for photolithoautotrophic metabolisms. To achieve this goal, two different photosynthetic microorganisms were used: the microalgae Parachlorella kessleri and the cyanobacterium Nostoc sp. MFCs were loaded with nonsterilized samples, sterilized samples, or sterilized culture medium of both microorganisms. Electric potential measurements were recorded for each group in single experiments or in continuum during light-dark cycles, and power and current densities were calculated. Our results indicate that the highest power and current density values were achieved when metabolically active microorganisms were present in the anode of the MFC. Moreover, when continuous measurements were performed during light-dark cycles, it was possible to see a positive response to light. Therefore, these BES could be used not only to detect chemoorganoheterotrophic metabolisms but also photolithoautotrophic metabolisms, in particular those involving oxygenic photosynthesis. Additionally, the positive response to light when using these BES could be employed to distinguish photosynthetic from nonphotosynthetic microorganisms in a sample.

Here, we present a new toxicity bioassay (CO2-TOX), able to detect toxic or inhibitory compounds in water samples, based on the quantification of Pseudomonas putida KT2440 CO2 production. The metabolically produced CO2 was measured continuously and directly in the liquid assay media, with a potentiometric gas electrode. The optimization studies were performed using as a model toxicant 3,5-DCP (3,5-dichlorophenol); later, heavy metals (Pb(2+), Cu(2+), or Zn(2+)) and a metalloid (As(5+)) were assayed. The response to toxics was evident after 15 min of incubation and at relatively low concentrations (e.g., 1.1 mg/L of 3,5-DCP), showing that the CO2-TOX bioassay is fast and sensitive. The EC50 values obtained were 4.93, 0.12, 6.05, 32.17, and 37.81 mg/L for 3,5-DCP, Cu(2+), Zn(2+), As(5+), and Pb(2+), respectively, at neutral pH. Additionally, the effect of the pH of the sample and the use of lyophilized bacteria were also analyzed showing that the bioassay can be implemented in different conditions. Moreover, highly turbid samples and samples with very low oxygen levels were measured successfully with the new instrumental bioassay described here. Finally, simulated samples containing 3,5-DCP or a heavy metal mixture were tested using the proposed bioassay and a standard ISO bioassay, showing that our test is more sensible to the phenol but less sensible to the metal mixtures. Therefore, we propose CO2-TOX as a rapid, sensitive, low-cost, and robust instrumental bioassay that could perform as an industrial wastewater-process monitor among other applications.