The global rise in urbanization and industrial activity has led to the production and incorporation of foreign contaminant molecules into ecosystems, distorting them and impacting human and animal ...health. Physical, chemical, and biological strategies have been adopted to eliminate these contaminants from water bodies under anthropogenic stress. Biotechnological processes involving microorganisms and enzymes have been used for this purpose; specifically, laccases, which are broad spectrum biocatalysts, have been used to degrade several compounds, such as those that can be found in the effluents from industries and hospitals. Laccases have shown high potential in the biotransformation of diverse pollutants using crude enzyme extracts or free enzymes. However, their application in bioremediation and water treatment at a large scale is limited by the complex composition and high salt concentration and pH values of contaminated media that affect protein stability, recovery and recycling. These issues are also associated with operational problems and the necessity of large-scale production of laccase. Hence, more knowledge on the molecular characteristics of water bodies is required to identify and develop new laccases that can be used under complex conditions and to develop novel strategies and processes to achieve their efficient application in treating contaminated water. Recently, stability, efficiency, separation and reuse issues have been overcome by the immobilization of enzymes and development of novel biocatalytic materials. This review provides recent information on laccases from different sources, their structures and biochemical properties, mechanisms of action, and application in the bioremediation and biotransformation of contaminant molecules in water. Moreover, we discuss a series of improvements that have been attempted for better organic solvent tolerance, thermo-tolerance, and operational stability of laccases, as per process requirements.
Cationic surfactants as antifungal agents Fait, M. Elisa; Bakas, Laura; Garrote, Graciela L. ...
Applied microbiology and biotechnology,
2019/1, Letnik:
103, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Fungi—in being responsible for causing diseases in animals and humans as well as environmental contaminations in health and storage facilities—represent a serious concern to health security. ...Surfactants are a group of chemical compounds used in a broad spectrum of applications. The recently considered potential employment of cationic surfactants as antifungal or fungistatic agents has become a prominent issue in the development of antifungal strategies, especially if such surface-active agents can be synthesized in an eco-friendly manner. In this review, we describe the antifungal effect and the reported mechanisms of action of several types of cationic surfactants and also include a discussion of the contribution of these surfactants to the inhibition of yeast-based-biofilm formation. Furthermore, the putative mechanism of arginine-based tensioactive compounds as antifungal agents and their applications are also analyzed.
Amino-acid-based surfactants are a group of compounds that resemble natural amphiphiles and thus are expected to have a low impact on the environment, owing to either the mode of surfactant ...production or its means of disposal. Within this context, arginine-based tensioactives have gained particular interest, since their cationic nature—in combination with their amphiphilic character—enables them to act as broad-spectrum biocides. This capability is based mainly on their interactive affinity for the microbial envelope that alters the latter’s structure and ultimately its function. In the work reported here, we investigated the efficiency of
N
α
-benzoyl arginine decyl- and dodecylamide against
Candida
spp. to further our understanding of the antifungal mechanism involved. For the assays, both a
Candida albicans
and a
Candida tropicalis
clinical isolates along with a
C. albicans
–collection strain were used as references. As expected, both arginine-based compounds proved to be effective against the strains tested through inhibiting both the planktonic and the sessile growth. Furthermore, atomic force microscopy techniques and lipid monolayer experiments enabled us to gain insight into the effect of the surfactant on the cellular envelope. The results demonstrated that all the yeasts treated exhibited changes in their exomorphologic structure, with respect to alterations in both roughness and stiffness, relative to the nontreated ones. This finding—in addition to the amphiphiles’ proven ability to insert themselves within this model fungal membrane—could explain the changes in the yeast-membrane permeability that could be linked to viability loss and mixed-vesicle release.
Paper-based works of art and documents of cultural importance kept in museums and libraries can show notorious signs of deterioration, including foxing stains, caused by fungal colonization. Some of ...the main chromophore agents of fungal origin that deteriorate paper and therefore affect paper cultural heritage both aesthetically and structurally are the group of pigments called melanins. Thus, knowledge of the diversity and features of fungal melanins and of the melanization pathways of fungi growing on paper is key to removing these pigments from paper-based works of cultural importance. This review provides an approach about the current knowledge of melanins synthesized by paper-colonizing fungi, their localization in the fungal structures, and their role in the deterioration of paper. This knowledge might contribute to developing new, effective, and sustainable strategies of restoration and conservation of historical documents and works of art based on paper.
Several filamentous fungi are able to concomitantly assimilate both aliphatic and polycyclic aromatic hydrocarbons that are the biogenic by-products of some industrial processes. Cytochrome P450 ...monooxygenases catalyze the first oxidation reaction for both types of substrate. Among the cytochrome P450 (CYP) genes, the family CYP52 is implicated in the first hydroxylation step in alkane-assimilation processes, while genes belonging to the family CYP53 have been linked with oxidation of aromatic hydrocarbons. Here, we perform a comparative analysis of CYP genes belonging to clans CYP52 and CYP53 in
Aspergillus niger
,
Beauveria bassiana
,
Metarhizium robertsii
(formerly
M. anisopliae
var.
anisopliae
), and
Penicillium chrysogenum
. These species were able to assimilate
n
-hexadecane,
n
-octacosane, and phenanthrene, exhibiting a species-dependent modification in pH of the nutrient medium during this process. Modeling of the molecular docking of the hydrocarbons to the cytochrome P450 active site revealed that both phenanthrene and
n
-octacosane are energetically favored as substrates for the enzymes codified by genes belonging to both CYP52 and CYP53 clans, and thus appear to be involved in this oxidation step. Analyses of gene expression revealed that CYP53 members were significantly induced by phenanthrene in all species studied, but only CYP52X1 and CYP53A11 from
B. bassiana
were highly induced with
n
-alkanes. These findings suggest that the set of P450 enzymes involved in hydrocarbon assimilation by fungi is dependent on phylogeny and reveal distinct substrate and expression specificities.
In the last two decades, a significant amount of work aimed at studying the ability of the white-rot fungus Coriolopsis rigida strain LPSC no. 232 to degrade lignin, sterols, as well as several ...hazardous pollutants like dyes and aliphatic and aromatic fractions of crude oil, including polycyclic aromatic hydrocarbons, has been performed. Additionally, C. rigida in association with arbuscular mycorrhizal fungi appears to enhance plant growth, albeit the physiological and molecular bases of this effect remain to be elucidated. C. rigida's ability to degrade lignin and lignin-related compounds and the capacity to transform the aromatic fraction of crude oil in the soil might be partially ascribed to its ligninolytic enzyme system. Two extracellular laccases are the only enzymatic components of its lignin-degrading system. We reviewed the most relevant findings regarding the activity and role of C. rigida LPSC no. 232 and its laccases and discussed the work that remains to be done in order to assess, more precisely, the potential use of this fungus and its extracellular enzymes as a model in several applied processes.
Abstract Tomato grey leaf spot is a fungal disease that provokes losses in tomato yield. The aim of this work is to analyse genomic differences among three isolates of Stemphylium lycopersici that ...differ in virulence and sporulation. The bioinformatics analysis led us to predict the identity of putative effectors, pathogenesis and virulence factors. Like the genome of other necrotrophic pathogens, Stemphylium encodes a wide spectrum of effectors, including an ample and diverse array of carbohydrate‐degrading enzymes. Interestingly, the number of predicted effectors was unrelated to virulence. Low virulence appeared to be associated with the presence of several double‐stranded RNAs from viruses as well as cellular processes related to protein degradation, redox and detoxifying processes and monoterpenes production. This is the first identification of the potential effectors of tomato– S . lycopersici interaction; nonetheless functional studies should be done.
A bibliographic analysis was carried out to update the state of knowledge about aquatic fungi belonging to the subkingdom Dikarya in the Southern Cone of South America. The exhaustive search resulted ...in 38 articles reported. These papers correspond to those on taxonomic, ecological and biogeographic topics and include studies from lotic environments of the temperate ecoregions of Chile and Argentina. A total of 325 aquatic fungal taxa were reported, of which 318 belong to the phylum Ascomycota and 7 to the phylum Basidiomycota. According to the subgroups of these aquatic fungi 17 taxa were aero-aquatic, 199 facultative and 109 Ingoldian fungi. Regarding the methodologies, in these studies the information was obtained mainly by using lignocellulosic substrates such as leaf litter and wood as fungal source and wet chamber traditional working technique. However, more studies are still needed using other few-reported perspectives for the region such as ecological and molecular approaches as well as analyses of water environments belonging to unexplored biomes. This information can contribute to a better understanding of aquatic fungal communities and their role in ecosystems of the Southern Cone of South America.
Two laccase isoenzymes were purified and characterized from the basidiomycete Coriolopsis rigida during transformation of the water-soluble fraction of “alpeorujo” (WSFA), a solid residue derived ...from the olive oil production containing high levels of toxic compounds. Zymogram assays of laccases secreted by the fungus growing on WSFA and WSFA supplemented with glucose showed two bands with isoelectric points of 3.3 and 3.4. The kinetic studies of the two purified isoenzymes showed similar affinity on 2,6-dimethoxyphenol and 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid), used as phenolic and non-phenolic model substrate, respectively. The molecular mass of both proteins was 66 kDa with 9% N-linked carbohydrate. Physico-chemical properties of the purified laccases from media containing WSFA were similar to those obtained from medium with glucose as the main carbon source. In-vitro studies performed with the purified laccases revealed a 42% phenol reduction of WSFA, as well as changes in the molecular mass distribution. These findings indicate that these laccases are involved in the process of transformation, via polymerization by the oxidation of phenolic compounds present in WSFA. A single laccase gene, containing an open reading frame of 1,488 bp, was obtained in PCR amplifications performed with cDNA extracted from mycelia grown on WSFA. The product of the gene shares 90% identity (95% similarity) with a laccase from Trametes trogii and 89% identity (95% similarity) with a laccase from Coriolopsis gallica. This is the first report on purification and molecular characterization of laccases directly involved in the transformation of olive oil residues.
Grape pomace (GP) from Vitis labrusca, the main byproduct from “American table wine” production, is recalcitrant to degradation, and its accumulation is a serious problem with negative environmental ...impacts. In this work, transformation of grape pomace using a steam pretreatment followed by incubation of GP during a 90-day period with six different fungi were evaluated. Several fungi tested reduced the phytotoxicity of water-soluble fraction (WSFd) from steam-pretreated GP after 90 days’ incubation to lettuce and tomato seeds. U. botrytis caused the largest effective phytotoxicity reduction of WSFd (used in the concentration range of 10–1.25% p/v) and was the only fungus causing the removal of monoaromatic compounds. Therefore, this procedure with U. botrytis effectively reduces the availability of phytotoxic monoaromatic compounds in GP, which opens a way for the development of guidelines for the management of these wastes and their potential use as organic amendments in agricultural soil.
•Grape pomace is a source of phytotoxic monoaromatic compounds.•Ulocladium botrytis LPSC 813 can grow on steam-pretreated grape pomace.•Ulocladium botrytis LPSC 813 removes phytotoxic monoaromatic compounds.•Ulocladium botrytis LPSC 813 causes effective phytotoxicity reduction of grape pomace.•Phytotoxicity reduction was confirmed on lettuce and tomato seeds.
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