Degradation of selected pharmaceutical and personal care products (PPCPs) by white-rot fungi

Today, more than 3,000 pharmaceutical and personal care products (PPCPs) are used and released into the environment at low doses but they are barely degraded in wastewater treatment plants. One of the potential alternatives to effectively degrade PPCPs is based on the use of white-rot fungi (WRF) and involves the oxidative action of extracellular fungal enzymes. The aim of this work is to study the potential ability of three WRF strains, an anamorph species of Bjerkandera sp. R1, Bjerkandera adusta and Phanerochaete chrysosporium, to degrade PPCPs belonging to different therapeutic groups: anti-depressants (citalopram and fluoxetine), antibiotics (sulfamethoxazole), anti-inflammatory drugs (diclofenac, ibuprofen and naproxen), anti-epileptics (carbamazepine), tranquilizers (diazepam) and fragrances (celestolide, galaxolide and tonalide). The results reported complete degradation of all the PPCPs except for fluoxetine and diazepam, which were partially removed in percentages from 23 to 57%. In the case of fragrances, these compounds were neither detected in the fungal cultures nor in the abiotic controls, indicating the possibility of volatilization during the experiment.     

Facile reduction of arsenate in methanogenic sludge

Due to the recent enactment of a stricter drinking water standard for arsenate, large quantities of arsenate-laden drinking water residuals will be disposed in municipal landfills. The objective of this study was to determine the role of methanogenic consortia on the conversion of arsenate. Methanogenic conditions commonly occur in mature municipal solid waste landfills. The results indicate the rapid and facile reduction of arsenate to arsenite in methanogenic sludge. Endogenous substrates in the sludge were sufficient to support the reductive biotransformation. However the rates of arsenate reduction were stimulated by the addition of exogenous electron donating substrates, such as H2, lactate or a mixture of volatile fatty acids. A selective methanogenic inhibitor stimulated arsenate reduction in microcosms supplied with H2, suggesting that methanogens competed with arsenate reducers for the electron donor. Rates of arsenate reduction increased with arsenate concentration up to 2 mM, higher concentrations were inhibitory. The electron shuttle, anthraquinone-2,6-disulfonate, used as a model of humic quinone moieties, was shown to significantly increase rates of arsenate reduction at substoichiometric concentrations. The presence of sulfur compounds, sulfate and sulfide, did not affect the rate of arsenate transformation but lowered the yield of soluble arsenite, due to the precipitation of arsenite with sulfides. The results taken as a whole suggest that arsenate disposed into anaerobic environments may readily be converted to arsenite increasing the mobility of arsenic. The extent of the increased mobility will depend on the concentration of sulfides generated from sulfate reduction.     

Effect of pH on the stability of Pleurotus eryngii versatile peroxidase during heterologous production in Emericella nidulans

Complementary DNA (cDNA) encoding the new versatile peroxidase from the ligninolytic basidiomycete Pleurotus eryngii has been expressed in the ascomycete Emericella nidulans. In recombinant E. nidulans cultures, the pH reached values as high as 8.3, correlating with a sharp decrease in peroxidase activity. Peroxidase was rapidly inactivated at alkaline pH, but was comparatively stable at acidic pH. The peroxidase inactivation in alkaline buffer could be reversed by adding Ca²⁺ and lowering the pH. However, reactivation did not result after incubating the enzyme in non-buffered E. nidulans cultures that reached pH 7.5. To optimize recombinant peroxidase production, the effect of controlling the pH in E. nidulans bioreactor cultures was studied. An extended growth period, and a significant increase in the recombinant peroxidase level (5.3-fold higher activity than in the bioreactor without pH control) was obtained when the pH was maintained at 6.8, showing that culture pH is an important parameter for recombinant peroxidase production.     

Continuous removal of endocrine disruptors by versatile peroxidase using a two‐stage system

The oxidant Mn³⁺‐malonate, generated by the ligninolytic enzyme versatile peroxidase in a two‐stage system, was used for the continuous removal of endocrine disrupting compounds (EDCs) from synthetic and real wastewaters. One plasticizer (bisphenol‐A), one bactericide (triclosan) and three estrogenic compounds (estrone, 17β‐estradiol, and 17α‐ethinylestradiol) were removed from wastewater at degradation rates in the range of 28–58 µg/L·min, with low enzyme inactivation. First, the optimization of three main parameters affecting the generation of Mn³⁺‐malonate (hydraulic retention time as well as Na‐malonate and H₂O₂ feeding rates) was conducted following a response surface methodology (RSM). Under optimal conditions, the degradation of the EDCs was proven at high (1.3–8.8 mg/L) and environmental (1.2–6.1 µg/L) concentrations. Finally, when the two‐stage system was compared with a conventional enzymatic membrane reactor (EMR) using the same enzyme, a 14‐fold increase of the removal efficiency was observed. At the same time, operational problems found during EDCs removal in the EMR system (e.g., clogging of the membrane and enzyme inactivation) were avoided by physically separating the stages of complex formation and pollutant oxidation, allowing the system to be operated for a longer period (～8 h). This study demonstrates the feasibility of the two‐stage enzymatic system for removing EDCs both at high and environmental concentrations. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:908–916, 2015     

System Matrix Analysis for Computed Tomography Imaging

In practical applications of computed tomography imaging (CT), it is often the case that the set of projection data is incomplete owing to the physical conditions of the data acquisition process. On the other hand, the high radiation dose imposed on patients is also undesired. These issues demand that high quality CT images can be reconstructed from limited projection data. For this reason, iterative methods of image reconstruction have become a topic of increased research interest. Several algorithms have been proposed for few-view CT. We consider that the accurate solution of the reconstruction problem also depends on the system matrix that simulates the scanning process. In this work, we analyze the application of the Siddon method to generate elements of the matrix and we present results based on real projection data.     

Development of regional characterization factors for aquatic eutrophication

Background, aim, and scope  

Life cycle assessment (LCA) has traditionally been considered a site-independent tool, but nowadays, there is a trend towards making LCA more site-dependent. Site-dependent characterization factors have been calculated for regional impact categories such as acidification, terrestrial and aquatic eutrophication, and smog. Specifically, for aquatic eutrophication, characterization factors have been proposed for large geographical areas (mainly European and North American countries). Those factors are not detailed enough for countries which present large geographical, climatic, and economical variability such as Spain. Therefore, this work aims to calculate the characterization factors and the normalization reference for aquatic eutrophication at a regional level, using Galicia (NW Spain), a region with increasing problems of eutrophication, as a case study. Finally, the comparison of the factors obtained here with literature values will be used to analyze the influence of spatial differentiation with increasing coverage of the causality chain.     

Bioremediation of HCH present in soil by the white-rot fungus Bjerkandera adusta in a slurry batch bioreactor

In the soil remediation process, the hydrophobic characteristics of pollutants and their affinity for soil matrix may be responsible for mass transfer limitations. The degradation of hexachlorocyclohexane (HCH) isomers present in a spiked soil by the white-rot Bjerkandera adusta was evaluated in a slurry system. Experiments in shaken flasks were performed to evaluate the action of the endogenous microflora, the adsorption of HCH on the fungal biomass and the potential synergic or antagonic actions between the microflora and the fungal biomass. The fungus significantly degraded the HCH isomers from the soil slurry in the following order: α≈γ>δ>β-HCH. The degradation process was further scaled in a 5-l reactor, where the solid load and concentration of the pollutant in the soil were evaluated. At optimal conditions, 100 g soil l⁻¹ and 100 mg total HCH l⁻¹, maximal degradations of 94.5%, 78.5% and 66.1% were attained after 30 d for γ-, α- and δ-HCH isomers, respectively, representing between 1.7 and 3.1-fold the values obtained at small scale. These results indicate that minimising mass transfer resistances is a key factor for HCH degradation from soil.     

Environmental assessment of the Atlantic mackerel (<Emphasis Type="Italic">Scomber scombrus</Emphasis>) season in the Basque Country. Increasing the timeline delimitation in fishery LCA studies

Purpose  

The purpose of this study was to evaluate the environmental impacts linked to fish extraction on a temporal basis, in order to analyze the effect that stock abundance variations may have on reporting environmental burdens. Inventory data for the North-East Atlantic Mackerel (NEAM) fishing season were collected over an 8-year period and used to carry out a life cycle assessment (LCA). The selected fishery corresponds to the Basque coastal purse seining fleet.     

Environmental assessment of black locust (<Emphasis Type="BoldItalic">Robinia pseudoacacia</Emphasis> L.)-based ethanol as potential transport fuel

Purpose  

Lignocellulosic ethanol has received special research interest, driven by concerns over high fuel prices, security of energy supplies, global climate change as well as the search of opportunities for rural economic development. A well-to-wheel analysis was conducted for ethanol obtained from black locust (Robinia pseudoacacia L.) by means of the life cycle assessment (LCA) methodology. This study assesses the environmental profile of using ethanol in mixtures E10 and E85 as transport fuel in comparison with conventional gasoline (CG). In addition, the best model of black locust cultivation was analysed under an environmental point of view.     

Erratum to: A new strain of Bjerkandera sp. production,purification and characterization of versatile peroxidase

World Journal of Microbiology and Biotechnology -