Potential of Trichoderma koningii to eliminate alachlor in the presence of copper ions

Heavy metal-tolerant bacteria Bacillus cereus BCS1 degrades pyrethroid in a soil-plant system

The heightened concern about the environmental impacts of pollutants drives interest in reducing their threats to humans and the environment. Bioremediating polluted sites under environmental stresses like biotic and abiotic poses significant challenges. This study aimed to isolate a bacterium that effectively degrades pyrethroids even under abiotic stresses involving heavy metals and biotic stresses with autochthonous factors. Here, a bacterial strain, Bacillus cereus BCS1 was isolated. The response surface methodology was established to quantify the environmental impacts on pyrethroid degradation. BCS1 effectively degraded pyrethroids across conditions at 21-36 °C, pH 6.5-8.0 and inoculum sizes 1.9-4.1 mg·L-1, exceeding 90% degradation. Notably, over 84% of β-cypermethrin (β-CP) was degraded even when exposed to various concentrations of lead (10-1000 mg·L-1), chromium (10-1000 mg·L-1), or cadmium (0.5-50 mg·L-1). Moreover, BCS1 significantly accelerated β-CP degradation in soil-plant systems, displaying biotic stress tolerance, with lower half-life values (10.1 and 9.5 d) in soil and higher removal (92.1% and 60.9%) in plants compared to controls (27.7 and 25.7 d), and (18.2% and 24.3%). This study presents a novel strain capable of efficiently degrading pyrethroids and displaying remarkable environmental stress resistance. Findings shed light on bioremediating organic pollutants in complex soil ecosystems.

Eco-friendly TEMPO/laccase/O2 biocatalytic system for degradation of Indigo Carmine: operative conditions and laccase inactivation

The biocatalytic system laccase/TEMPO/O₂ has attracted the attention of researchers over the past two decades. A variety of applications for the system include organic synthesis, modification of cellulose, and oxidative degradation of environmental contaminants. A rigorous and predictable quantitative assessment of the change in enzymatic activity under the influence of a mediator is important for such a system. In this study, the operative conditions for carrying out a model reaction for the degradation of the synthetic dye Indigo Carmine in the presence of Trametes versicolor laccase/TEMPO were determined and the enzyme inactivation under the action of a mediator and substrate was studied. The long-term stability of Trametes versicolor laccase was assessed and the regression model of the response surface of laccase activity under the influence of TEMPO was created. It has been shown that laccase is inactivated in the presence of TEMPO, but the addition of the dye, CuSO₄ or CuCl₂ reduces this effect. The system under study can be used repeatedly for the Indigo Carmine decolorization, however, a gradual falling rate during the process is observed from cycle to cycle. This is due to two reasons - firstly, a decrease in the enzyme activity with each batch and secondly, the consumption of the mediator (22% within 5 days). Relatively high enzyme activity (>40%) is maintained after 73 cycles (1 portion of IC contained 25 μM) using 500 μM TEMPO and 0.12 U mL^-1 laccase. The laccase/TEMPO system has shown its effectiveness in the treatment of artificial wastewater containing high concentrations of Indigo carmine (0.5 g L^-1). In this case, the dye solution becomes 100% colorless within 5 hours in the presence of dye bath components and within 7.5 hours in a buffer solution.

Fungal biodegradation of chlorinated herbicides: an overview with an emphasis on 2,4-D in Argentina

Chlorinated herbicides are one of the main types of pesticide used in agriculture. In Argentina, 2,4-dichlorophenoxyacetic acid (2,4-D) is the most applied herbicide for the control of broadleaf weeds, but the risks it poses for the environment and human health are cause for great concern. A promising technology to remove this kind of pollutants, or neutralize them in such a way that they become less or non-toxic, is the use of degrading or detoxifying microorganisms from contaminated sites. Filamentous fungi can bioremediate xenobiotics thanks to their efficient enzymatic machinery. However, most studies on the degradation of 2,4-D have been carried out with bacteria, and little is known about whether it can be efficiently biodegraded by fungi. In the environment, fungal strains and native microbiota may detoxify contaminants through mechanisms like biosorption, bioabsortion, biotransformation, and/or degradation. Whether these processes occur separately or simultaneously depends on the metabolic ability of the strains that conform the microbial community. Another important concern when attempting to introduce detoxifying microorganisms into a contaminated environment is the GRAS ("Generally Recognized As Safe") assessment or status. These are studies that help predict a biodegrading microorganism's pathogenicity, toxicity, and infectivity before in situ application. This application, moreover, is regulated by different legal frameworks. The present review aims to outline the main aspects of 2,4-D degradation by fungi, and to summarize the current state of research on the topic in Argentina.

Microplastic-Induced Oxidative Stress in Metolachlor-Degrading Filamentous Fungus Trichoderma harzianum

While there has been intensive research on the influence of microplastics (MPs) on aquatic organisms and humans, their effect on microorganisms is relatively little-known. The present study describes the response of the Trichoderma harzianum strain to low-density polyethylene (LDPE) microparticles. MPs, either separately or with metolachlor (MET), were added to the cultures. Initially, MP was not found to have a negative effect on fungal growth and MET degradation. After 72 h of cultivation, the content of fungal biomass in samples with MPs was almost three times higher than that in the cultures without MPs. Additionally, a 75% degradation of the initial MET was observed. However, due to the qualitative and quantitative changes in individual classes of phospholipids, cell membrane permeability was increased. Additionally, MPs induced the overproduction of reactive oxygen species. The activity of superoxide dismutase and catalase was also increased in response to MPs. Despite these defense mechanisms, there was enhanced lipid peroxidation in the cultures containing the LDPE microparticles. The results of the study may fill the knowledge gap on the influence of MPs on filamentous fungi. The findings will be helpful in future research on the biodegradation of contaminants coexisting with MPs in soil.

Environmental and molecular approach to dye industry waste degradation by the ascomycete fungus Nectriella pironii

Textile industry effluents and landfill leachate contain chemicals such as dyes, heavy metals and aromatic amines characterized by their mutagenicity, cytotoxicity and carcinogenicity. The aim of the present study was investigation of the ascomycete fungus N. pironii isolated from urban postindustrial textile green space for its ability to grow and retain metabolic activity in the presence of the dye industry waste. Research focused mainly on dyes, heavy metals and aromatic amines, which had been detected in landfill leachate via HPLC-MS/MS analysis. Presence of all tested compounds as well as leachate in the growth medium clearly favored the growth of fungal biomass. Only slight growth limitation was observed in the presence of 50 mg L-1 o-tolidine. The fungus eliminated o-tolidine as well as dyes at all tested concentrations. The presence of metals slightly influenced the decolorization of the azo dyes; however, it was still similar to 90%. During fungal growth, o-tolidine was hydroxylated and/or converted to toluidine and its derivatives. Laccase and cytochrome P450 involvement in this process has been revealed. The results presented in the paper provide a valuable background for the development of a fungus-based system for the elimination of toxic pollutants generated by the textile industry.

Solid-state fermentation by Aspergillus niger and Trichoderma koningii improves the quality of tea dregs for use as feed additives

This study evaluated the ability of Aspergillus niger and Trichoderma koningii to improve the quality of tea dregs (TDs) through solid-state fermentation as well as the value of the fermented tea dregs (FTDs) produced for use as bio-feed additives. After fermentation, FTDs differed in color and structure. Fermentation with A. niger and T. koningii increased the contents of crude protein, crude fiber, neutral detergent fiber, and acid detergent fiber of TDs. Compared to the unfermented group, the contents of reducing sugar, total flavonoids, total polyphenols, and theasaponins were increased in A. niger FTDs, while in T. koningii FTDs caffeine was completely degraded, the theasaponins were lower, and the contents of reducing sugar and caffeine higher. Regarding free amino acids, A. niger FTDs had the highest content of total amino acids, total essential amino acids, total non-essential amino acids, total aromatic amino acids, total branched-chain amino acids, and total non-protein amino acids, and all types of essential amino acids, followed by T. koningii FTDs and the control TDs. Fungal fermentation had similar effects on the content of various hydrolytic amino acids as those on above free amino acids, and increased the content of bitter and umami components. The composition of essential amino acids of TDs or FTDs was similar to that of the standard model, except for sulfur-containing amino acids and isoleucine. Solid-state fermentation with A. niger and T. koningii effectively improved the nutritional value of TDs, increased the contents of functional substances, and improved the flavor of TDs. This study demonstrated a feasible approach to utilize TDs that not only increases animal feed resources, but also reduces the production of resource waste and pollution.

Trichoderma harzianum metabolites disturb Fusarium culmorum metabolism: Metabolomic and proteomic studies

Trichoderma species are well known for producing various secondary metabolites in response to different fungal pathogens. This paper reports the effects of the metabolites produced during one-day cultivation of Trichoderma harzianum on the growth and development of the popular pathogen Fusarium culmorum. Inhibition of the growth of the pathogen and production of secondary metabolites including zearalenone was observed on Petri dishes. The presence of proteins such as cytochrome c oxidase subunit 4, glutathione-independent glyoxalase HSP31, and putative peroxiredoxin pmp20 in the extract-treated culture indicated oxidative stress, which was confirmed by the presence of a higher amount of catalase and dismutase in the later hours of the culture. A larger amount of enolase and glyceraldehyde 3-phosphate dehydrogenase resulted in faster growth, and the overexpression of stress protein and Woronin body major protein indicated the activation of defense mechanisms. In addition, a cardinal reduction in major mycotoxin production was noted.

Myco-remediation of Chlorinated Pesticides: Insights Into Fungal Metabolic System

Synthetic chemicals including organochlorine pesticides pose environment and health hazard due to persistent and bio-accumulation property. Majority of them are recognized as endocrine disruptors. Fungi are ubiquitous in nature and employs efficient enzymatic machinery for the biotransformation and degradation of toxic, recalcitrant pollutants. This review critically discusses the organochlorine biotransformation process mediated by fungi and highlights the role of enzymatic system responsible for biotransformation, especially distribution of dehalogenase homologs among fungal classes. It also explores the potential use of fungal derived biomaterial, mainly chitosan as an adsorbing biomaterial for pesticides and heavy metals removal. Further, prospects of employing fungus to over-come the existing bioremediation limitations are discussed. The study highlights the potential scope of utilizing fungi for initial biotransformation purposes, preceding final biodegradation by bacterial species under environmental conditions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-021-00940-8.

Spatiotemporal pattern models for bioaccumulation of pesticides in common herbaceous and woody plants

Pesticides are widely used in agriculture, but they can bioaccumulate in plants, entering the food chain and potentially threaten human health. Thus, this study explored the spatiotemporal patterns of pesticide bioaccumulation in plants from soil using a spatiotemporal model. Air temperature (T_Air) and relative humidity (RH_Air) were selected as the principal spatiotemporal indicators to characterize the seasonal and geographical variation of the pesticide bioaccumulation factors (BAFs; i.e., the pesticide concentration ratio of plant to soil) of the leaves of common plants. The simulation results indicate that hot and dry climates typically increase the pesticide BAFs by enhancing the transpiration rate of plants. For example, the annual average BAF of alachlor was 5.75 in Arizona, while the BAFs in states with cold and humid weather, such as Maine, were below 2.00. Additionally, the monthly average BAF of alachlor during hot seasons can be double that of other seasons in the same region. For some pesticides, the simulated BAF intervals were consistent with those reported in the literature, whereas for others, the results were inconsistent. The major reasons for these inconsistencies include differences in the pesticide application scenarios, the distribution of pesticides in different compartments, and insufficient field data for some pesticides. We also applied the simulated BAFs of pesticide in plant leaves to address the seasonal and geographical health risks of herbivores, which could help regulate pesticide standards in ecological soils.

Confrontation assays and mycotoxin treatment reveal antagonistic activities of Trichoderma and the fate of Fusarium mycotoxins in microbial interaction

Mycotoxins are toxic fungal metabolites, contaminating cereal grains in field or during processing and storage periods. These environmental contaminants pose great threats to humans and animals' health due to their toxic effects. Type A trichothecenes, fumonisins and fusaric acid (FA) are commonly detected mycotoxins produced by various Fusarium species. Trichoderma spp. are promising antagonists in agriculture for their activities against plant pathogens, and also regarded as potential candidates for bioremediation of environmental contaminants. Managing toxigenic fungi by antagonistic Trichoderma is regarded as a sustainable and eco-friendly strategy for mycotoxin control. However, the metabolic activities of Trichoderma on natural occurring mycotoxins were less investigated. Our current work comprehensively explored the activities of Trichoderma against type A trichothecenes, fumonisins and FA producing Fusarium species via co-culture competition and indirect volatile assays. Furthermore, we investigated metabolism of type A trichothecenes and FA in Trichoderma isolates. Results indicated that Trichoderma were capable of bio-transforming T-2 toxin, HT-2 toxin, diacetoxyscirpenol and neosolaniol into their glycosylated forms and one Trichoderma strain could bio transform FA into low toxic fusarinol. These findings proved that Trichoderma isolates could manage toxigenic Fusarium via direct competition and volatile-mediated indirect inhibition. In addition, these antagonists possess defensive systems against mycotoxins for self-protection, which enriches our understanding on the interaction mechanism of Trichoderma spp. on toxigenic fungus.

Genome Sequence of Trichoderma lixii MUT3171, A Promising Strain for Mycoremediation of PAH-Contaminated Sites

Mono- and polycyclic aromatic hydrocarbons (PAHs) are widespread and recalcitrant pollutants that threaten both environmental and human health. By exploiting the powerful enzymatic machinery of fungi, mycoremediation in contaminated sites aims at removing a wide range of pollutants in a cost-efficient and environmentally friendly manner. Next-generation sequencing (NGS) techniques are powerful tools for understanding the molecular basis of biotransformation of PAHs by selected fungal strains, allowing genome mining to identify genetic features of biotechnological value. Trichoderma lixii MUT3171, isolated from a historically PAH-contaminated soil in Italy, can grow on phenanthrene, as a sole carbon source. Here, we report the draft genome sequence of T. lixii MUT3171 obtained with high-throughput sequencing method. The genome of T. lixii MUT3171 was compared with other 14 Trichoderma genomes, highlighting both shared and unique features that can shed a light on the biotransformation of PAHs. Moreover, the genes potentially involved in the production of important biosurfactants and bioactive molecules have been investigated. The gene repertoire of T. lixii MUT3171 indicates a high degrading potential and provides hints on putative survival strategies in a polluted environment.

Laccase activity of the ascomycete fungus Nectriella pironii and innovative strategies for its production on leaf litter of an urban park

A laccase-producing ascomycete fungus was isolated from soil collected around the premises of a textile dye factory and identified as Nectriella pironii. Efficient laccase production was achieved via the synergistic action of 1 mM copper sulfate and ferulic acid. Extracts of rapeseed oil cake, grass hay, and leaf litter collected in a pocket urban park were used for enzyme production. The highest laccase activity (3,330 U/L) was observed in the culture grown on the leaf litter extract. This is the first report on biosynthesis of laccase by N. pironii. This is also the first study on utilization of naturally fallen park leaves as a substrate for fungal laccase production. The extracellular enzyme possessing laccase activity was purified to homogeneity by ion-exchange and gel filtration chromatographic techniques. The amino acid sequence of the protein revealed highest similarity to the laccase enzyme produced by Stachybotrys chartarum—and considerable homology to those produced by other fungal species. The purified laccase possessed a molecular mass of 50 kDa. The enzyme had an optimum pH of 2.0 or 6.0 and retained more than 50% of residual activity after 3 hours of incubation at pH 3.0–10.6 or 4.0–9.0 when 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid or 2,6-dimethoxyphenol, respectively, were used. Dithiothreitol, β-mercaptoethanol, and sodium azide at 1 mM concentration strongly inhibited the laccase activity, while in the presence of 50 mM urea, the enzyme was found to retain 25% of its activity. The laccase was able to decolorize more than 80% of Indigo Carmine, Remazol Brilliant Blue R, Reactive Orange 16, and Acid Red 27 dyes within 1 h. The possibility of leaf litter use for the production of the laccase enzyme from N. pironii (IM 6443), exhibiting high pH stability and degradative potential, makes it a promising tool for use in different environmental and industrial operations.

Biotransformation and detoxification of chloroacetanilide herbicides by Trichoderma spp. with plant growth-promoting activities

Due to the increasing use of chlorinated organic compounds, environmental pollution is a key issue in agricultural and industrial areas. In this study, biodegradation of chloroacetanilide herbicides, such as alachlor and metolachlor, by eight fungal strains of Trichoderma spp. originating from different microorganism collections was investigated. The tested fungi converted 80-99% of alachlor and 40-79% of metolachlor after 7 days of incubation. Biotransformation of herbicides was performed mainly by dechlorination and hydroxylation reactions. Eight alachlor metabolites and four byproducts of metolachlor conversion were detected in Trichoderma cultures, including two metolachlor intermediates for the first time identified in fungi. Moreover, in the cultures of six Trichoderma strains supplemented with chloroacetanilides, a decrease in toxicity was observed toward tested Artemia franciscana crustaceans. Simultaneously, 7 days after the application of the spores of T. koningii IM 0956, T. citrinoviride IM 6325, T. harzianum KKP 534, T. viride KKP 792 and T. virens DSM 1963 the length of roots and shoots of rapeseed seedlings treated with alachlor or metolachlor significantly increased. All tested strains exhibited plant growth-promoting traits, such as siderophore production, 1-aminocyclopropane-1-carboxylate deaminase (ACCD) activity, and phosphate solubilization, even in the presence of chloroacetanilide herbicides.

Ecofriendly laccases treatment to challenge micropollutants issue in municipal wastewaters

In this study, a multidisciplinary approach investigated the enzymatic degradation of micropollutants in real, not modified, municipal wastewaters of a plant located in Italy. Stir Bar Sorptive Extraction combined to Gas Chromatography-Mass Spectrometric detection (SBSE-GC-MS) was applied to profile targeted pollutants in wastewaters collected after the primary sedimentation (W1) and the final effluent (W2). Fifteen compounds were detected at ng/L - μg/L, including pesticides, personal care products (PCPs) and drugs. The most abundant micropollutants were bis(2-ethylhexyl) phthalate, diethyl phthalate and ketoprofen. Laccases of Trametes pubescens MUT 2400 were very active against all the target micropollutants: except few cases, their concentration was reduced more than 60%. Chemical analysis and environmental risk do not always come together. To verify whether the treated wastewaters can represent a stressor for the aquatic ecosystem, toxicity was also evaluated. Raphidocelis subcapitata and Lepidium sativum tests showed a clear ecotoxicity reduction, even though they did not evenly respond. Two in vitro tests (E-screen test and MELN assay) were used to evaluate the estrogenic activity. Treatments already operating in the plant (e.g. activated sludge) partially reduced the estradiol equivalent concentration, and it was almost negligible after the laccases treatment. The results of this study suggest that laccases of T. pubescens are promising biocatalysts for the micropollutants transformation in wastewaters and surface waters.

Assessment of oxidative stress and phospholipids alterations in chloroacetanilides-degrading Trichoderma spp

To investigate the induction of oxidative stress and antioxidant response in the chloroacetanilides-degrading Trichoderma spp. under alachlor and metolachlor exposure, a comparative analysis using popular biomarkers was employed. An increased intracellular level of reactive oxygen species (ROS; especially superoxide anion [O₂^-]) as well as products of lipid and protein oxidation after 24 h incubation with the herbicides confirmed chloroacetanilide-induced oxidative stress in tested Trichoderma strains. However, the considerable decline in the ROS levels and the carbonyl group content (biomarkers of protein peroxidation) in a time-dependent manner and changes in the antioxidant enzyme activities indicated an active response against chloroacetanilide-induced oxidative stress and the mechanism of tolerance in tested fungi. Moreover, the tested herbicides clearly modified the phospholipids (PLs) content in Trichoderma spp. in the stationary phase of growth, which was manifested through the difference in phosphatidic acid (PA), phosphatidylethanolamine (PE) and phosphatidylcholines (PC) levels. Despite enhanced lipid peroxidation and changes in PLs in most tested fungi, only a slight modification in membrane integrity of Trichoderma spp. under chloroacetanilides exposure was noted. The obtained results suggest that the alterations in the antioxidant system and the PLs profile of Trichoderma spp. might be useful biomarkers of chloroacetanilide-induced oxidative stress.

4-n-nonylphenol degradation by the genus Metarhizium with cytochrome P450 involvement

In this study, the ability of 4-n-nonylphenol (4-n-NP) elimination by fungal species belonging to the genus Metarhizium was investigated. The occurrence of 35 metabolites from 4-n-NP degradation was confirmed. For the first time, based on the obtained results, the 4-n-NP biodegradation pathway distinctive for the genus Metarhizium was proposed. Principal Component Analysis (PCA) indicated that despite the similar elimination pathway in all the examined Metarhizium species, there are significant differences in the kinetics of degradation of 4-n-NP. Oxidation of the terminal methyl group of the aliphatic chain leading to the formation of carboxylic acids coupled with the removal of terminal carbon is characteristic of M. robertsii and M. guizhouense, whereas metabolites with a hydroxyl group in the distal part of the nonyl chain distinguish M. lepidiotae and M. majus. Additionally, this study verified the participation of cytochrome P450 in the elimination of the xenobiotic by Metarhizium as experimentally proven for M. robertsii.

Shifting interactions among bacteria, fungi and archaea enhance removal of antibiotics and antibiotic resistance genes in the soil bioelectrochemical remediation

BACKGROUND

Antibiotics and antibiotic resistance genes (ARGs) are two pollutants in soil, especially ARGs as one of the top three threats to human health. The performance of soil microbial fuel cells (MFCs) fuelled with antibiotics was investigated.

RESULTS

In this study, soil MFCs spiked with tetracycline exhibited optimal bioelectricity generation, which was 25% and 733% higher than those of MFCs spiked with sulfadiazine and control, respectively. Compared with the non-electrode treatment, not only did functional micro-organisms change in open- and closed-circuit treatments, but also the microbial affinities, respectively, increased by 50% and 340% to adapt to higher removal of antibiotics. For the open-circuit treatment, the ineffective interspecific relation of micro-organisms was reduced to assist the removal efficiency of antibiotics by 7-27%. For the closed-circuit treatment, an intensive metabolic network capable of bioelectricity generation, degradation and nitrogen transformation was established, which led to 10-35% higher removal of antibiotics. Importantly, the abundances of ARGs and mobile genetic element (MGE) genes decreased after the introduction of electrodes; especially in the closed-circuit treatment, the highest reduction of 47% and 53% was observed, respectively.

CONCLUSIONS

Soil MFCs possess advantages for the elimination of antibiotics and ARGs with sevenfold to eightfold higher electricity generation than that of the control treatment. Compared with sulphonamides, the enhancement removal of tetracycline is higher, while both potential ARG propagation risk is reduced in soil MFCs. This study firstly synchronously reveals the relationships among bacteria, fungi and archaea and with ARGs and MGE genes in soil bioelectrochemical systems.

Red-emissive nitrogen doped carbon quantum dots for highly selective and sensitive fluorescence detection of the alachlor herbicide in soil samples

We report the synthesis of red-emissive nitrogen-doped carbon quantum dots and their applications in the highly selective and sensitive detection of the alachlor herbicide in soil samples.