New Concepts in the Evaluation of Biodegradation/Persistence of Chemical Substances Using a Microbial Inoculum

The European REACH Regulation (Registration, Evaluation, Authorization of CHemical substances) implies, among other things, the evaluation of the biodegradability of chemical substances produced by industry. A large set of test methods is available including detailed information on the appropriate conditions for testing. However, the inoculum used for these tests constitutes a “black box.” If biodegradation is achievable from the growth of a small group of specific microbial species with the substance as the only carbon source, the result of the test depends largely on the cell density of this group at “time zero.” If these species are relatively rare in an inoculum that is normally used, the likelihood of inoculating a test with sufficient specific cells becomes a matter of probability. Normally this probability increases with total cell density and with the diversity of species in the inoculum. Furthermore the history of the inoculum, e.g., a possible pre-exposure to the test substance or similar substances will have a significant influence on the probability. A high probability can be expected for substances that are widely used and regularly released into the environment, whereas a low probability can be expected for new xenobiotic substances that have not yet been released into the environment. Be that as it may, once the inoculum sample contains sufficient specific degraders, the performance of the biodegradation will follow a typical S shaped growth curve which depends on the specific growth rate under laboratory conditions, the so called F/M ratio (ratio between food and biomass) and the more or less toxic recalcitrant, but possible, metabolites. Normally regulators require the evaluation of the growth curve using a simple approach such as half-time. Unfortunately probability and biodegradation half-time are very often confused. As the half-time values reflect laboratory conditions which are quite different from environmental conditions (after a substance is released), these values should not be used to quantify and predict environmental behavior. The probability value could be of much greater benefit for predictions under realistic conditions. The main issue in the evaluation of probability is that the result is not based on a single inoculum from an environmental sample, but on a variety of samples. These samples can be representative of regional or local areas, climate regions, water types, and history, e.g., pristine or polluted. The above concept has provided us with a new approach, namely “Probabio.” With this approach, persistence is not only regarded as a simple intrinsic property of a substance, but also as the capability of various environmental samples to degrade a substance under realistic exposure conditions and F/M ratio

Bacterial Bioluminescent Biosensor Characterisation for On-line Monitoring of Heavy Metals Pollutions in Waste Water Treatment Plant Effluents

International audienc

Raman Spectroscopy: Toward a Portable Food Quality-Warning System

Food waste is one of the main problems contributing to climate change as its piling up in landfills produces the greenhouse gas methane. Food waste occurs at every stage of food production; however, the major source of food waste occurs at businesses that supply food to consumers. Industry 4.0 technologies have shown promises in helping reduce food waste in food supply chains. However, more innovative technologies such as Raman spectroscopy holds great promise in helping reduce food waste, but this has largely been ignored in the literature. In this context, we propose a portable Raman platform to monitor food quality during transportation. The developed system was tested in conditions mimicking those present in a refrigerated truck by analyzing chicken samples stored at temperatures of 4 °C. Raman spectra were acquired for non-packaged and packaged samples over the duration of 30 days resulting in 6000 spectra. The analysis of Raman spectra revealed that the system was able to detect noticeable changes in chicken quality starting day six. The main Raman bands contributing to this change were amide I and tyrosine. The proposed system will offer the potential to reduce food losses during transportation by consistently checking the food quality over time

Constructing living buildings: a review of relevant technologies for a novel application of biohybrid robotics

Biohybrid robotics takes an engineering approach to the expansion and exploitation of biological behaviours for application to automated tasks. Here, we identify the construction of living buildings and infrastructure as a high-potential application domain for biohybrid robotics, and review technological advances relevant to its future development. Construction, civil infrastructure maintenance and building occupancy in the last decades have comprised a major portion of economic production, energy consumption and carbon emissions. Integrating biological organisms into automated construction tasks and permanent building components therefore has high potential for impact. Live materials can provide several advantages over standard synthetic construction materials, including self-repair of damage, increase rather than degradation of structural performance over time, resilience to corrosive environments, support of biodiversity, and mitigation of urban heat islands. Here, we review relevant technologies, which are currently disparate. They span robotics, self-organizing systems, artificial life, construction automation, structural engineering, architecture, bioengineering, biomaterials, and molecular and cellular biology. In these disciplines, developments relevant to biohybrid construction and living buildings are in the early stages, and typically are not exchanged between disciplines. We, therefore, consider this review useful to the future development of biohybrid engineering for this highly interdisciplinary application.publishe

Microcapteurs électrochimiques pour des mesures durables en Environnement-Santé et Agroalimentaire

National audienc

Reporter Proteins in Whole-Cell Optical Bioreporter Detection Systems, Biosensor Integrations, and Biosensing Applications

Whole-cell, genetically modified bioreporters are designed to emit detectable signals in response to a target analyte or related group of analytes. When integrated with a transducer capable of measuring those signals, a biosensor results that acts as a self-contained analytical system useful in basic and applied environmental, medical, pharmacological, and agricultural sciences. Historically, these devices have focused on signaling proteins such as green fluorescent protein, aequorin, firefly luciferase, and/or bacterial luciferase. The biochemistry and genetic development of these sensor systems as well as the advantages, challenges, and common applications of each one will be discussed

Spatial and temporal variability in the potential of river water biofilms to degrade p-nitrophenol

© 2016 Elsevier Ltd In order to predict the fate of chemicals in the environment, a range of regulatory tests are performed with microbial inocula collected from environmental compartments to investigate the potential for biodegradation. The abundance and distribution of microbes in the environment is affected by a range of variables, hence diversity and biomass of inocula used in biodegradation tests can be highly variable in space and time. The use of artificial or natural biofilms in regulatory tests could enable more consistent microbial communities be used as inocula, in order to increase test consistency. We investigated spatial and temporal variation in composition, biomass and chemical biodegradation potential of bacterial biofilms formed in river water. Sampling time and sampling location impacted the capacity of biofilms to degrade p-nitrophenol (PNP). Biofilm bacterial community structure varied across sampling times, but was not affected by sampling location. Degradation of PNP was associated with increased relative abundance of Pseudomonas syringae. Partitioning of the bacterial metacommunity into core and satellite taxa revealed that the P. syringae could be either a satellite or core member of the community across sampling times, but this had no impact on PNP degradation. Quantitative PCR analysis of the pnpA gene showed that it was present in all samples irrespective of their ability to degrade PNP. River biofilms showed seasonal variation in biomass, microbial community composition and PNP biodegradation potential, which resulted in inconsistent biodegradation test results. We discuss the results in the context of the mechanisms underlying variation in regulatory chemical degradation tests

Review of micro/nanotechnologies for microbial biosensors

A microbial biosensor is an analytical device with a biologically integrated transducer that generates a measurable signal indicating the analyte concentration. This method is ideally suited for the analysis of extracellular chemicals and the environment, and for metabolic sensory regulation. Although microbial biosensors show promise for application in various detection fields, some limitations still remain such as poor selectivity, low sensitivity, and impractical portability. To overcome such limitations, microbial biosensors have been integrated with many recently developed micro/nanotechnologies and applied to a wide range of detection purposes. This review article discusses micro/nanotechnologies that have been integrated with microbial biosensors and summarizes recent advances and the applications achieved through such novel integration. Future perspectives on the combination of micro/nanotechnologies and microbial biosensors will be discussed, and the necessary developments and improvements will be strategically deliberated.clos

Développement de bioessais à l'aide de bactéries génétiquement modifiées pour la détection de polluants environnementaux

La Décision Européenne n2455/2001/CE a publié en 2001 une liste de 33 substances à détecter dans l eau. Nous avons abordé, avec des méthodes biologiques innovantes, le problème de la détection de deux de ces substances, le tributylétain (TBT), un biocide couramment utilisé dans les peintures antisalissures et interdit dans de nombreux pays, et l atrazine, un herbicide. La bactérie Escherichia coli TBT3, qui a été obtenue par mutagenèse aléatoire, est sensible aux organoétains mais son mécanisme d induction est inconnu. L étude au niveau moléculaire de cette bactérie a permis d aboutir à un mécanisme vraisemblable de la réponse au TBT, grâce à la localisation d un promoteur et d un nouveau régulateur transcriptionnel, responsables de l induction de la bioluminescence. Un dispositif innovant a été fabriqué pour distinguer les peintures interdites contenant du TBT de celle n en contenant pas. Un bioessai simple est proposé comme alternative aux analyses chimiques. En parallèle, une nouvelle bactérie, dont la bioluminescence est inductible par l atrazine, a été développée en détournant le système de dégradation de l atrazine provenant de la bactérie environnementale Pseudomonas sp. ADP. Cette nouvelle bactérie bioluminescente permettra une détection simple et rapide de l atrazine dans l eau et le sol.The European decision n2455/2001/EC published in 2001 a list of 33 priority substances to be detected in water. We addressed the problem of the detection with innovative biological methods for two substances, the tributyltin (TBT) a biocide broadly used in antifouling paint and now banned for many countries and the herbicide atrazine. The bacterium E. coli TBT3, which was made by random mutagenesis, is sensitive to organotins but its induction mechanism remained unknown. A comprehensive molecular study of this bacterium led to a plausible mechanism of TBT response, thanks to the localization of a promoter and a new transcriptional regulator YgaV involved in the induction of bioluminescence. An innovative device was made to distinguish prohibited paints containing TBT from those without TBT. A simple alternative bioassay is now proposed to the conventional analyses. In a second step, a new bacterium, whose bioluminescence was activated by atrazine, was also developed by using the biodegradation system of atrazine from an environmental bacterium Pseudomonas sp. ADP. This new bioluminescent bacteria will allow a simple and rapid way to detect atrazine both in water and in soil.NANTES-BU Sciences (441092104) / SudocSudocFranceF