The disaccharide trehalose plays a crucial role in multiple facets of the stress biology of yeasts and fungi. Here, we evaluate the properties, cellular and ecophysiological roles, metabolism, and ...stress-protection mechanisms of trehalose. We integrate disparate sources of knowledge across these topics, and bring new information about the mechanisms by which trehalose stabilises biomacromolecules and how trehalose metabolism is regulated thus giving rise to its diverse roles in fungi including stress protector, carbohydrate reserve, and regulatory/signaling molecule. We also present new findings about the effect of trehalose on microbial adaptation, complexity and spatio-temporal heterogeneity of microbial populations, and implications for industrial processes that apply fungi. Based on the elucidation of the structures of enzymes involved in trehalose synthesis, their catalytic mechanisms, and the regulation of trehalose synthesis, we discuss prospects for the development of more-efficient fungicides. Current humanitarian crises, such as overpopulation, global warming, malnutrition, immunocompromised conditions, and usage of immunosuppressant drugs, are making the incidence of human pathogens increases. Furthermore, fungal infections can be difficult to treat due to the conserved biochemistry between human and fungi cells. Serendipitously, however, trehalose is not synthesised by mammals, which makes trehalose synthesis an interesting target for the development of new therapies.
•Trehalose plays a crucial role in fitness of fungi.•Fungi are submitted to various stresses in nature, in hosts and biotech systems.•Trehalose improves productivity of fungi employed in biotechnological processes.•Trehalose enhances stress biology of fungi, including virulence of pathogens.•Inhibition of trehalose synthesis reduces virulence of pathogenic fungi.
Plant-derived biomass is the most abundant biogenic carbon source on Earth. Despite this, only a small clade of organisms known as white-rot fungi (WRF) can efficiently break down both the ...polysaccharide and lignin components of plant cell walls. This unique ability imparts a key role for WRF in global carbon cycling and highlights their potential utilization in diverse biotechnological applications. To date, research on WRF has primarily focused on their extracellular ‘digestive enzymes’ whereas knowledge of their intracellular metabolism remains underexplored. Systems biology is a powerful approach to elucidate biological processes in numerous organisms, including WRF. Thus, here we review systems biology methods applied to WRF to date, highlight observations related to their intracellular metabolism, and conduct comparative extracellular proteomic analyses to establish further correlations between WRF species, enzymes, and cultivation conditions. Lastly, we discuss biotechnological opportunities of WRF as well as challenges and future research directions.
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Mycology; Biotechnology
In industry, filamentous fungi have a prominent position as producers of economically relevant primary or secondary metabolites. Particularly, the advent of genetic engineering of filamentous fungi ...has led to a growing number of molecular tools to adopt filamentous fungi for biotechnical applications. Here, we summarize recent developments in fungal biology, where fungal host systems were genetically manipulated for optimal industrial applications. Firstly, available inducible promoter systems depending on carbon sources are mentioned together with various adaptations of the Tet-Off and Tet-On systems for use in different industrial fungal host systems. Subsequently, we summarize representative examples, where diverse expression systems were used for the production of heterologous products, including proteins from mammalian systems. In addition, the progressing usage of genomics and functional genomics data for strain improvement strategies are addressed, for the identification of biosynthesis genes and their related metabolic pathways. Functional genomic data are further used to decipher genomic differences between wild-type and high-production strains, in order to optimize endogenous metabolic pathways that lead to the synthesis of pharmaceutically relevant end products. Lastly, we discuss how molecular data sets can be used to modify products for optimized applications.
Carbohydrate active enzymes (CAZymes) are vital for the lignocellulose-based biorefinery. The development of hypersecreting fungal protein production hosts is therefore a major aim for both academia ...and industry. However, despite advances in our understanding of their regulation, the number of promising candidate genes for targeted strain engineering remains limited. Here, we resequenced the genome of the classical hypersecreting
mutant
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and identified the causative point of mutation to reside in the F-box protein-encoding gene, NCU09899. The corresponding deletion strain displayed amylase and invertase activities exceeding those of the carbon catabolite derepressed strain Δ
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, while glucose repression was still mostly functional in Δ
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Surprisingly, RNA sequencing revealed that while plant cell wall degradation genes are broadly misexpressed in Δ
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, only a small fraction of CAZyme genes and sugar transporters are up-regulated, indicating that EXO-1 affects specific regulatory factors. Aiming to elucidate the underlying mechanism of enzyme hypersecretion, we found the high secretion of amylases and invertase in Δ
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to be completely dependent on the transcriptional regulator COL-26. Furthermore, misregulation of COL-26, CRE-1, and cellular carbon and nitrogen metabolism was confirmed by proteomics. Finally, we successfully transferred the hypersecretion trait of the
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disruption by reverse engineering into the industrially deployed fungus
using CRISPR-Cas9. Our identification of an important F-box protein demonstrates the strength of classical mutants combined with next-generation sequencing to uncover unanticipated candidates for engineering. These data contribute to a more complete understanding of CAZyme regulation and will facilitate targeted engineering of hypersecretion in further organisms of interest.
The fungi-based technology provided encouraging scenarios in the transition from a conventionally based economic system to the potential security of sources closely associated with the agricultural ...sphere such as the agriculture. In recent years, the intensification of fungi-based processes has generated significant gains, additionally to the production of materials with significant benefits and strong environmental importance. Furthermore, the growing concern for human health, especially in the agriculture scenario, has fostered the investigation of organisms with high biological and beneficial potential for use in agricultural systems. Accordingly, this study offered a comprehensive review of the diversity of the soil fungal microbiome and its main applications in a biotechnological approach aimed at agriculture and food chain-related areas. Moreover, the spectrum of opportunities and the extensive optimization platform for obtaining fungi compounds and metabolites are discussed. Finally, future perspectives regarding the insurgency of innovations and challenges on the broad rise of visionary solutions applied to the biotechnology context are provided.
Graphical Abstract
Agro-industrial wastes pose environmental health hazards to humans and animals; yet, they are abundant, readily availabile and cheap, and therefore provide opportunities for their valorization with ...microorganisms to produce value-added, nutrient-rich animal feed. This study (i) determined, in vitro, optimum growth conditions for Aspergillus niger and Mucor sp. and (ii) subsequently evaluated their ability to ferment and valorize watermelon wastes for protein enhancement. Changes in protein contents of sterilized and unsterilized watermelon substrates were determined after 5, 10, and 15 days of fermentation with mono- and co-cultures of A. niger and Mucor sp. at 25 °C. Different growth conditions (pH, temperature, different concentrations of ammonium nitrate, sodium nitrate, urea, sodium chloride and thiamine) of synthetic media variously supported mycelial growth of A. niger and Mucor sp., either as mono- or co-culture; optimum growth conditions were selected for fermentation of watermelon wastes. Protein contents of sterilized and unsterilized watermelon substrates were enhanced by fermentation: (i) percentage increase in protein contents of sterilized watermelon fermented with mono-cultures of A. niger, Mucor sp. and co-culture of A. niger and Mucor sp. were 35.91, 18.94 and 22.18 %, respectively; (ii) protein contents in unsterilized watermelon substrates also increased by 23.94, 9.49, and 14.88 % for mono-cultures of A. niger and Mucor sp. and their co-culture, respectively. Overall, the observed trend in the increase of protein contents in the sterilized and unsterilized substrates by the test fungi was: mono-culture of A. niger > co-culture of A. niger and Mucor sp. > mono-culture of Mucor sp. Crude fat, fiber and ash contents significantly (p ≤ 0.05) decreased in both sterilized and unsterilized watermelon substrates, whereas the carbohydrate content increased significantly (p ≤ 0.05) in the substrates. These findings highlight the potential of watermelon waste as valuable bioresource and feedstock for valorization into livestock feed through fungal biotechnology. Future works to augment findings are suggested.
Fungi are of excellent value nutritionally, and of great importance to vegetarians. Edible mushrooms are excellent sources of protein, have low-fat content and are free of cholesterol. They are ...easily cultivable and are consumed either in fresh or processed form. Yeasts and filamentous fungi secrete a plethora of important enzymes in the growth medium together with other secondary metabolites. Most of these are hydrolytic in nature being employed in different food processing industries as well as in refinement of fodder quality. Edible filamentous fungi producing these enzymes present an added advantage for their use in food and feed. In this article these aspects will be discussed along with the results from edible mushroom
Termitomyces clypeatus, producing a wide variety of hydrolytic enzymes and products, from our laboratory. It is likely that the functional understanding of different enzyme classes will provide new applications within the food industry in the future.
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•Genetic tools to improve the industrially relevant fungus A. vadensis are needed.•Agrobacterium tumefaciens-mediated transformation (ATMT) was adapted to A.vadensis.•ATMT and SynBio ...facilitate the exploitation of A. vadensis at the industrial level.
In the last years, many research efforts have been applied for the development of filamentous fungi as hosts for heterologous protein production. Aspergillus vadensis CBS 113365, a close relative of the industrial workhorse Aspergillus niger, has been suggested as a more suitable cell factory as it does not acidify the culture medium and produces very low levels of secreted proteases. Therefore, efficient methods and tools that allow the genetic manipulation and exploitation of this biotechnologically relevant fungus are needed. To date, only protoplast-mediated transformation and classical cloning strategies have been implemented for A. vadensis genetic modification, which decreases the exploitation capacity of this fungus at the industrial level. In this study, we have adapted and implemented an Agrobacterium tumefaciens-mediated transformation protocol for A. vadensis for the first time, and applied the FungalBraid system to genetically modify this species by means of synthetic biology. As proof of concept, we have successfully complemented and fluorescently labelled a uridine auxotrophic A. vadensis pyrA- strain and generated A. vadensis mutants carrying the Penicillium expansum-based expression cassette for the heterologous production of the antifungal protein PeAfpA from P. expansum. Even though we have yet to find the conditions that trigger PeAfpA production in this species, the implementation of the ATMT method reported here, along with the application of the FungalBraid system, will greatly aid in this task and will facilitate the exploitation of A. vadensis as a fungal workhorse for protein production for multiple biotechnological applications.
Abstract
The use of white-rot fungi as a biotechnological tool for cleaning the environment of recalcitrant pollutants has been under evaluation for several years. However, it is still not possible ...to find sufficiently detailed investigations of this subject to conclude that these fungi can decontaminate the environment. In the present review, we have summarized and discussed evidence about the potential of white-rot fungi to degrade such pollutants as polycyclic aromatic hydrocarbons, dyes or antibiotics as an example of the complex structures that these microorganisms can attack. This review also discusses field experiment results and limitations of white-rot fungi trials from contaminated sites. Moreover, the use of catabolic potential of white-rot fungi in biopurification systems (biobeds) is also discussed. The current status and future perspectives of white-rot fungi, as a viable biotechnological alternative for improvement of environmental health are noted.
Coumarins are a structurally varied set of 2H-chromen-2-one compounds categorized also as members of the benzopyrone group of secondary metabolites. Coumarin derivatives attract interest owing to ...their wide practical application and the unique reactivity of fused benzene and pyrone ring systems in molecular structure. Coumarins have their own specific fingerprints as antiviral, antimicrobial, antioxidant, anti-inflammatory, antiadipogenic, cytotoxic, apoptosis, antitumor, antitubercular, and cytotoxicity agents. Natural products have played an essential role in filling the pharmaceutical pipeline for thousands of years. Biological effects of natural coumarins have laid the basis of low-toxic and highly effective drugs. Presently, more than 1300 coumarins have been identified in plants, bacteria, and fungi. Fungi as cultivated microbes have provided many of the nature-inspired syntheses of chemically diverse drugs. Endophytic fungi bioactivities attract interest, with applications in fields as diverse as cancer and neuronal injury or degeneration, microbial and parasitic infections, and others. Fungal mycelia produce several classes of bioactive molecules, including a wide group of coumarins. Of promise are further studies of conditions and products of the natural and synthetic coumarins’ biotransformation by the fungal cultures, aimed at solving the urgent problem of searching for materials for biomedical engineering. The present review evaluates the fungal coumarins, their structure-related peculiarities, and their future therapeutic potential. Special emphasis has been placed on the coumarins successfully bioprospected from fungi, whereas an industry demand for the same coumarins earlier found in plants has faced hurdles. Considerable attention has also been paid to some aspects of the molecular mechanisms underlying the coumarins’ biological activity. The compounds are selected and grouped according to their cytotoxic, anticancer, antibacterial, antifungal, and miscellaneous effects.
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