Removal of Endocrine Disrupting Chemicals by the Ligninolytic Enzyme Versatile Peroxidase

This thesis proposal is about the application of ligninolytic enzymes and reactive species of Mn3+ in the degradation of recalcitrant compounds, including dyes, pharmaceuticals and personal care products, and endocrine disrupting compounds. These compounds have a polymeric structure which is hard to degrade; therefore, it is necessary to use degradation agents with high oxidizing potential. These studies were conducted in laboratory assays in order to maximize the degradation of these compounds. Subsequently, application arises in enzyme reactors, evaluating the parameters that ensure high operational efficiency and processing capacity

The impact of endocrine-disrupting chemicals on the environment and their potential biotransformation by white-rot fungi and their oxidative enzymes.

e search of new technologies suitable for the treatment of wastewater containing endocrine disrupting chemicals (EDCs) such as bisphenol A (BPA), triclosan (TCS), estrone (E1), 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) is a challenge since existing traditional wastewater treatment plants (WWTPs) are not able to eliminate them completely. Even at concentrations of ng/L, EDCs have an impact in the endocrine system of the fauna producing morphological deformities, reduced overall growth, reduced sperm quality and delayed ovulation, sex reversal male to female, among others. Efforts have been put in the study of different post-treatments to remove the residual concentration of EDCs present in WWTP effluents. The most frequently used technologies are advanced oxidation processes (AOPs) such as photocatalysis, photodegradation, sonolysis, ozonolysis, amongst others. In general, these processes have high degradation rate but they have low selectivity and high costs. In addition, AOPs can be a cause of concern itself since they may render harmful by-products or transformation products which can have similar or increased estrogenicity of that of the parent compound. A biological alternative may be use of white-rot fungi (WRF) or their lignin modifying enzymes (LMEs) to treat wastewater containing EDCs. From an operational point of view, the use of LMEs in in vitro systems, compared to the use of WRF in in vivo systems, is easier and cheaper since no aseptic conditions are needed. Among the LMEs, laccase is the most extensively studied enzyme for the degradation of BPA, TCS, E1, E2 and EE2 whereas peroxidases (LiP, MnP and VP) have not been studied in such level of detail

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

8 páginas, 4 figuras, 2 tablas -- PAGS nros. 115-122The lignin modifying enzymes (LMEs) secreted by a new white rot fungus isolated from Chile were studied in this work. This fungus has been identified as a new anamorph of Bjerkandera sp. based on the sequences of the ribosomal DNA and morphological analysis at light microscopy showing hyaline hyphae without clamp connection, cylindrical conidia and lack of sexual forms, similar to those reported in other Bjerkandera anamorphs. The characterization of the culture medium for the highest LMEs production was performed in flask cultures, with a formulation of the culture medium containing high levels of glucose and peptone. The highest Mn-oxidizing peroxidase activity (1,400 U/L) was achieved on day 6 in Erlenmeyer flasks. Four peroxidases (named R1B1, R1B2, R1B3 and R1B4), have been purified by using ion-exchange and exclusion molar chromatographies. All of them showed typical activity on Mn2+ and exhibited Mn-independent activity against 2,6-dimethoxyphenol. R1B4 showed also activity on veratryl alcohol (pH 3) indicating that this enzyme belongs to the versatile peroxidase family. The high VP production capacities of this strain, as well as the enzymatic characteristics of the LMEs suggest that it may be successfully used in the degradation of recalcitrant compoundsThis study has been supported by the Spanish projects S-0505/AMB0100, PGIDIT06PXIB265088PR and CTQ2007-66788, and the European project EUI2008-03703. Authors thanks M. Jurado and B. Casas by your help in ITS analysis and electrophoretic techniques. R. Taboada thanks to BES-2008-006977 PhD fellowship. T. Lu-Chau wishes to thank the Isabel Barreto program from the Galician Government for the economical support provided during the development of this workPeer reviewe

Polymerization of coniferyl alcohol by Mn3+-mediated (enzymatic) oxidation : Effects of H2O2 concentration, aqueous organic solvents, and pH

The objective of this study was to evaluate the ability of one versatile peroxidase and the biocatalytically generated complex Mn(III)-malonate to polymerize coniferyl alcohol (CA) to obtain dehydrogenation polymers (DHPs) and to characterize how closely the structures of the formed DHPs resemble native lignin. Hydrogen peroxide was used as oxidant and Mn2+ as mediator. Based on the yields of the polymerized product, it was concluded that the enzymatic reaction should be performed in aqueous solution without organic solvents at 4.5pH6.0 and with 0.75H(2)O(2):CA ratio1. The results obtained from the Mn3+-malonate-mediated polymerization showed that the yield was almost 100%. Reaction conditions had, however, effect on the structures of the formed DHPs, as detected by size exclusion chromatography and pyrolysis-GC/MS. It can be concluded that from the structural point of view, the optimal pH for DHP formation using the presently studied system was 3 or 4.5. Low H2O2/CA ratio was beneficial to avoid oxidative side reactions. However, the high frequency of - linkages in all cases points to dimer formation between monomeric CA rather than endwise polymerization. (c) 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:81-90, 2018Peer reviewe

Effects of pre-operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study an international prospective cohort study

We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care. We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care