Laccase-based biosensors for detection of phenolic compounds Rodríguez-Delgado, Melissa M.; Alemán-Nava, Gibrán S.; Rodríguez-Delgado, José Manuel ...
TrAC, Trends in analytical chemistry (Regular ed.),
December 2015, 2015-12-00, 2015-12, Letnik:
74
Journal Article
Recenzirano
Odprti dostop
•Transduction principles, laccase sources and immobilization method.•Laccase from Trametes, Aspergillus and Ganoderma genres employed in biosensing.•Amperometry is the transduction principle most ...used in laccase-biosensor design.•Lifetime and stability up to 10 months were achieved by electrochemical devices.•Optical transduction principle shows the best limit of detection at trace levels.
Monitoring of phenolic compounds in the food industry and for environmental and medical applications has become more relevant in recent years. Conventional methods for detection and quantification of these compounds, such as spectrophotometry and chromatography, are time consuming and expensive. However, laccase biosensors represent a fast method for on-line and in situ monitoring of these compounds. We discuss the main transduction principles. We divide the electrochemical principle into amperometric, voltammetric, potentiometric and conductometric sensors. We divide optical transducers into fluorescence and absorption. The amperometric transducer method is the most widely studied and used for laccase biosensors. Optical biosensors present higher sensitivity than the other biosensors. Laccase production is dominated by a few fungus genera: Trametes, Aspergillus, and Ganoderma. We present an overview of laccase biosensors used for the determination of phenolic compounds in industrial applications.
Mexico ranks 9th in the world in crude oil reserves, 4th in natural gas reserves in America and it is also highly rich in renewable energy sources (solar, wind, biomasss, hydropower and geothermal). ...However, the potential of this type of energy has not been fully exploited. Hydropower is the renewable energy source with the highest installed capacity within the country (11,603MW), while geothermal power capacity (958MW) makes Mexico to be ranked 4th in the use of this energy worldwide. Wind energy potential is concentrated in five different zones, mainly in the state of Oaxaca, and solar energy has a high potential due to Mexico's ideal location in the so called Solar Belt. Biomass energy has the highest potential (2635 to 3771PJ/year) and has been the subject of the highest number of research publications in the country during the last 30 years (1982–2012). Universidad Nacional Autonoma de Mexico has led research publications in hydropower, wind, solar and biomass energy and Instituto de Investigaciones Electricas in geothermal energy during this period. According to the General Law for Climate Change the country has set the goal of generating 35% of its energy needs from renewable sources by 2024. This paper presents an overview of the renewable energy options available in Mexico, current status, main positive results to date and future potential. It also analyses barriers hindering improvements and proposes pertinent solutions.
Hourly-resolved aerosol chemical speciation data can be a highly powerful tool to determine the source origin of atmospheric pollutants in urban environments. Aerosol mass concentrations of seventeen ...elements (Na, Mg, Al, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr and Pb) were obtained by time (1 h) and size (PM2.5 particulate matter < 2.5 μm) resolved aerosol samples analysed by Particle Induced X-ray Emission (PIXE) measurements. In the Marie Curie European Union framework of SAPUSS (Solving Aerosol Problems by Using Synergistic Strategies), the approach used is the simultaneous sampling at two monitoring sites in Barcelona (Spain) during September-October 2010: an urban background site (UB) and a street canyon traffic road site (RS). Elements related to primary non-exhaust traffic emission (Fe, Cu), dust resuspension (Ca) and anthropogenic Cl were found enhanced at the RS, whereas industrial related trace metals (Zn, Pb, Mn) were found at higher concentrations at the more ventilated UB site. When receptor modelling was performed with positive matrix factorization (PMF), nine different aerosol sources were identified at both sites: three types of regional aerosols (regional sulphate (S) - 27%, biomass burning (K) - 5%, sea salt (Na-Mg) - 17%), three types of dust aerosols (soil dust (Al-Ti) - 17%, urban crustal dust (Ca) - 6%, and primary traffic non-exhaust brake dust (Fe-Cu) - 7%), and three types of industrial aerosol plumes-like events (shipping oil combustion (V-Ni) - 17%, industrial smelters (Zn-Mn) - 3%, and industrial combustion (Pb-Cl) - 5%, percentages presented are average source contributions to the total elemental mass measured). The validity of the PMF solution of the PIXE data is supported by very good correlations with external single particle mass spectrometry measurements. Some important conclusions can be drawn about the PM2.5 mass fraction simultaneously measured at the UB and RS sites: (1) the regional aerosol sources impact both monitoring sites at similar concentrations regardless their different ventilation conditions; (2) by contrast, local industrial aerosol plumes associated with shipping oil combustion and smelters activities have a higher impact on the more ventilated UB site; (3) a unique source of Pb-Cl (associated with combustion emissions) is found to be the major (82%) source of fine Cl in the urban agglomerate; (4) the mean diurnal variation of PM2.5 primary traffic non-exhaust brake dust (Fe-Cu) suggests that this source is mainly emitted and not resuspended, whereas PM2.5 urban dust (Ca) is found mainly resuspended by both traffic vortex and sea breeze; (5) urban dust (Ca) is found the aerosol source most affected by land wetness, reduced by a factor of eight during rainy days and suggesting that wet roads may be a solution for reducing urban dust concentrations.
The use of Nile Red for rapid monitoring of the neutral lipid content in microalgae has gained interest over the last decade, since neutral lipids are feedstock for renewable transportation fuel. In ...this review, we discuss the main considerations needed to make an NR protocol reliable for staining neutral lipids in microalgae. Cell wall permeability must be enhanced by using stain carriers: DMSO (5% v/v to 25% v/v), glycerol (0.1 to 0.125mg/mL), or EDTA (3.0 to 3.8mg/mL). Temperatures between 30 and 40°C facilitate the diffusion of NR through the cell wall without incurring excess quenching. Good NR-lipid interaction requires using a low NR/cell ratio; the NR concentration must be between 0.25μg/mL and 2.0μg/mL, and the cell concentration >5×104cells/mL. In order to have the maximum and stable NR fluorescence, it is necessary to scan the excitation/emission wavelengths for up to a 40-min of incubation time. We outline a five-step method to customize the Nile Red protocol to a specific strain: 1) Evaluate the strain's suitability by checking for the presence of neutral lipid, 2) Select of the best excitation/emission wavelength, 3) Optimization of incubation time, stain carrier, dye concentration, and temperature, 4) Prepare single-strain algal cultures with different lipid contents to calibrate NR fluorescence with neutral-lipid content, and 5) Correlate NR fluorescence intensity to neutral lipid content for the same strain. Once the protocol is customized, the NR method allows for rapid and reliable monitoring of neutral lipid content of a microalgae strain.
•A Nile Red review reliable monitoring of neutral lipid content of a microalgae strain is performed.•Optimization of Nile red is needed for different microalgae strains.•Parameter ranges are given for protocol optimization.•A five step methodology is proposed to develop customized Nile Red protocol.
Arthrospira platensis biomass was used in order to obtain functional lipophilic compounds through green extraction technologies such as supercritical carbon dioxide fluid extraction (SFE) and ...microwave-assisted extraction (MAE). The temperature (T) factor was evaluated for MAE, while for SFE, pressure (P), temperature (T), and co-solvent (ethanol) (CS) were evaluated. The maximum extraction yield of the obtained oleoresin was (4.07% ± 0.14%) and (4.27% ± 0.10%) for SFE and MAE, respectively. Extracts were characterized by gas chromatography mass spectrometry (GC-MS) and gas chromatography flame ionization detector (GC-FID). The maximum contents of functional lipophilic compounds in the SFE and MAE extracts were: for carotenoids 283 ± 0.10 μg/g and 629 ± 0.13 μg/g, respectively; for tocopherols 5.01 ± 0.05 μg/g and 2.46 ± 0.09 μg/g, respectively; and for fatty acids 34.76 ± 0.08 mg/g and 15.88 ± 0.06 mg/g, respectively. In conclusion, the SFE process at P 450 bar, T 60 °C and CS 53.33% of CO₂ produced the highest yield of tocopherols, carotenoids and fatty acids. The MAE process at 400 W and 50 °C gives the best extracts in terms of tocopherols and carotenoids. For yield and fatty acids, the MAE process at 400 W and 70 °C produced the highest values. Both SFE and MAE showed to be suitable green extraction technologies for obtaining functional lipophilic compounds from Arthrospira platensis.
At the 3MV Tandetron accelerator of the LABEC laboratory of INFN (Florence, Italy) an external beam facility is fully dedicated to PIXE-PIGE measurements of the elemental composition of atmospheric ...aerosols. All the elements with Z>10 are simultaneously detected by PIXE typically in one minute. This setup allows us an easy automatic positioning, changing and scanning of samples collected by different kinds of devices: long series of daily PM (Particulate Matter) samples can be analysed in short times, as well as size-segregated and high time-resolution aerosol samples.
Thanks to the capability of detecting all the crustal elements, PIXE-PIGE analyses are unrivalled in the study of mineral dust: consequently, they are very effective in the study of natural aerosols, like, for example, Saharan dust intrusions. Among the detectable elements there are also important markers of anthropogenic sources, which allow effective source apportionment studies in polluted urban environments using a multivariate method like Positive Matrix Factorization (PMF).
Examples regarding recent monitoring campaigns, performed in urban and remote areas, both daily and with high time resolution (hourly samples), as well as with size selection, are presented. The importance of the combined use of the Particle Induced Gamma Ray emission technique (PIGE) and of other complementary (non-nuclear) techniques is highlighted.
Abstract
In the attempt to adhere to the UK’s 2050 Net-Zero Strategy, more attention has been given to energy-centric decision-making over the regeneration of housing estates. Whole Life Carbon ...Assessment (WLCA) is the methodology used for the evaluation of the overall carbon dioxide equivalent (CO2e) emissions of building projects over their lifecycle. The WLCA studies are mostly not understood by different stakeholders and are less effective in reducing the Global Warming Potential (GWP) impacts in the development of regeneration scenarios. This paper is part of a larger study on a multistakeholder lifecycle-based sustainability assessment framework and aims to further explore whether retrofitting can outperform the existing and new build scenarios for lower GWP impacts, and intends to examine the use of WLCA for the development of a regeneration scenario. The research consists of a single-case case study employing co-design workshops, surveys, and WLCA experiments. The community’s preferred regeneration scenario has been developed through knowledge mobility and co-design workshops with the members of the community and a UCL team of designers and researchers. The WLCA of different regeneration scenarios (existing building, different refurbishment scenarios, and a previously approved redevelopment scheme) has been conducted using the data from desk-based research, site surveys, building regulations, retrofit case studies and guidelines, and the planning documents of the council’s previously approved new build scheme. The results of the WLCA support the current studies in favour of the refurbishment scenarios over the demolition and rebuilding of the estate, and make a case for the necessity of understanding the GWP in design development to reduce the GWP of regeneration scenarios.
In this paper, a new way to apportion the absorption coefficient (babs) of carbonaceous atmospheric aerosols starting from a multi-wavelength optical analysis is shown. This methodology can ...disentangle and quantify the contribution to total absorption of equivalent black carbon (EBC) emitted by wood burning (EBCWB) and fossil fuel (EBCFF) as well as brown carbon (BrC) due to incomplete combustion. The method uses the information gathered at five different wavelengths in a renewed and upgraded version of the approach usually referred to as Aethalometer model. Moreover, we present the results of an apportionment study of carbonaceous aerosol sources performed in a rural area and in a coastal city, both located in the North-West of Italy. Results obtained by the proposed approach are validated against independent measurements of levoglucosan and radiocarbon. At the rural site the EBCWB and EBCFF relative contributions are about 40% and 60% in winter and 15% and 85% in summer, respectively. At the coastal urban site, EBCWB and EBCFF are about 15% and 85% during fall. The OC contribution to the wood burning source at the rural site results approximately 50% in winter and 10% in summer and about 15% at the coastal urban site in fall. The new methodology also provides a direct measurement of the absorption Ångström exponent of BrC (αBrC) which resulted αBrC = 3.95 ± 0.20.
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•Aerosol light absorption at several λs due to Black and Brown Carbon is measured.•The value of Ångström exponent of Brown Carbon is directly extracted by raw data.•The new apportionment procedure disentangles fossil and wood burning contributions.•Equivalent Black Carbon and Organic Carbon are separately apportioned.•The procedure is validated against independent Levoglucosan and 14C determination.
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