Almost one century after the Sir Alexander Fleming's fortuitous discovery of penicillin and the identification of the fungal producer as Penicillium notatum, later Penicillium chrysogenum (currently reidentified as Penicillium rubens), the molecular mechanisms behind the massive production of penicillin titers by industrial strains could be considered almost fully characterized. However, this filamentous fungus is not only circumscribed to penicillin, and instead, it seems to be full of surprises, thereby producing important metabolites and providing expanded biotechnological applications. This review, in addition to summarizing the classical role of P. chrysogenum as penicillin producer, highlights its ability to generate an array of additional bioactive secondary metabolites and enzymes, together with the use of this microorganism in relevant biotechnological processes, such as bioremediation, biocontrol, production of bioactive nanoparticles and compounds with pharmaceutical interest, revalorization of agricultural and food-derived wastes or the enhancement of food industrial processes and the agricultural production.

In recent years, the study of volatile compounds has sparked interest due to their implications in signaling and the enormous variety of bioactive properties attributed to them. Despite the absence of analysis methods standardization, there are a multitude of tools and databases that allow the identification and quantification of volatile compounds. These compounds are chemically heterogeneous and their diverse properties are exploited by various fields such as cosmetics, the food industry, agriculture and medicine, some of which will be discussed here. In virtue of volatile compounds being ubiquitous and fast chemical messengers, these molecules mediate a large number of interspecific and intraspecific interactions, which are key at an ecological level to maintaining the balance and correct functioning of ecosystems. This review briefly summarized the role of volatile compounds in inter- and intra-specific relationships as well as industrial applications associated with the use of these compounds that is emerging as a promising field of study.

Edible fungi, commonly known as mushrooms, are precious medicinal and edible homologous gifts from nature to us. Edible fungal polysaccharides (EFPs) are a variety of bioactive macromolecular which isolated from fruiting bodies, mycelia or fermentation broths of edible or medicinal fungus. Increasing researches have confirmed that EFPs possess multiple biological activities both in vitro and in vivo settings, including antioxidant, antiviral, anti-inflammatory, immunomodulatory, anti-tumor, hypoglycemic, hypolipidemic, and regulating intestinal flora activities. As a result, they have emerged as a prominent focus in the healthcare, pharmaceutical, and cosmetic industries. Fungal EFPs have safe, non-toxic, biodegradable, and biocompatible properties with low immunogenicity, bioadhesion ability, and antibacterial activities, presenting diverse potential applications in the food industries, cosmetic, biomedical, packaging, and new materials. Moreover, varying raw materials, extraction, purification, chemical modification methods, and culture conditions can result in variances in the structure and biological activities of EFPs. The purpose of this review is to provide comprehensively and systematically organized information on the structure, modification, biological activities, and potential applications of EFPs to support their therapeutic effects and health functions. This review provides new insights and a theoretical basis for prospective investigations and advancements in EFPs in fields such as medicine, food, and new materials.

The intestine tract is a vital site for the body to acquire nutrients, serving as the largest immune organ. Intestinal health is crucial for maintaining a normal physiological state. Abundant microorganisms reside in the intestine, colonized in a symbiotic manner. These microorganisms can generate various metabolites that influence host physiological activities. Microbial metabolites serve as signaling molecules or metabolic substrates in the intestine, and some intestinal microorganisms act as probiotics and promote intestinal health. Researches on host, probiotics, microbial metabolites and their interactions are ongoing. This study reviews the effects of gut bacteria and their metabolites on intestinal health to provide useful references for animal husbandry.

Cyanobacteria are ubiquitously distributed in nature and are the most abundant photoautotrophs on Earth. Their long evolutionary history reveals that cyanobacteria have a remarkable capacity and strong adaptive tendencies to thrive in a variety of conditions. Thus, they can survive successfully, especially in harsh environmental conditions such as salty environments, high radiation, or extreme temperatures. Among others, salt stress because of excessive salt accumulation in salty environments, is the most common abiotic stress in nature and hampers agricultural growth and productivity worldwide. These detrimental effects point to the importance of understanding the molecular mechanisms underlying the salt stress response. While it is generally accepted that the stress response mechanism is a complex network, fewer efforts have been made to represent it as a network. Substantial evidence revealed that salt-tolerant cyanobacteria have evolved genomic specific mechanisms and high adaptability in response to environmental changes. For example, extended gene families and/or clusters of genes encoding proteins involved in the adaptation to high salinity have been collectively reported. This chapter focuses on recent advances and provides an overview of the molecular basis of halotolerance mechanisms in salt‑tolerant cyanobacteria as well as multiple regulatory pathways. We elaborate on the major protective mechanisms, molecular mechanisms associated with halotolerance, and the global transcriptional landscape to provide a gateway to uncover gene regulation principles. Both knowledge and omics approaches are utilized in this chapter to decipher the mechanistic insights into halotolerance. Collectively, this chapter would have a profound impact on providing a comprehensive understanding of halotolerance in salt‑tolerant cyanobacteria.

Molecular mechanisms underlying insect-pathogenic fungal tolerance to solar ultraviolet (UV) damage have been increasingly understood. This chapter reviews the methodology established to quantify fungal response to solar UV radiation, which consists of UVB and UVA, and characterize a pattern of the solar UV dose (damage) accumulated from sunrise to sunset on sunny summer days. An emphasis is placed on anti-UV mechanisms of fungal insect pathogens in comparison to those well documented in model yeast. Principles are discussed for properly timing the application of a fungal pesticide to improve pest control during summer months. Fungal UV tolerance depends on either nucleotide excision repair (NER) or photorepair of UV-induced DNA lesions to recover UV-impaired cells in the darkness or the light. NER is a slow process independent of light and depends on a large family of anti-UV radiation (RAD) proteins studied intensively in model yeast but rarely in non-yeast fungi. Photorepair is a rapid process that had long been considered to depend on only one or two photolyases in filamentous fungi. However, recent studies have greatly expanded a genetic/molecular basis for photorepair-dependent photoreactivation that serves as a primary anti-UV mechanism in insect-pathogenic fungi, in which photolyase regulators required for photorepair and multiple RAD homologs have higher or much higher photoreactivation activities than do photolyases. The NER activities of those homologs in dark reactivation cannot recover the severe UV damage recovered by their activities in photoreactivation. Future studies are expected to further expand the genetic/molecular basis of photoreactivation and enrich principles for the recovery of insect-pathogenic fungi from solar UV damage.

Fatty acids and their derivatives are indispensable biomolecules in all organisms, and can be used as intermediates in the synthesis of pharmaceuticals, biofuels and pesticides, and thus their demand has increased dramatically in recent years. In addition to serving as structural components of cell membranes and metabolic energy, fatty acids and their derivatives can also be used as signal transduction and regulatory bioactive molecules to regulate cell functions. Biosynthesis of fatty acids and their derivatives through microbial catalysis provides green and alternative options to meet the goal. However, the low biosynthetic titer of fatty acids and their derivatives limits their industrial production and application. In this review, we first summarize the metabolic pathways and related enzymes of fatty acids and their derivatives biosynthesis. Then, the strategies and research progress of biosynthesis of fatty acids and derivatives through metabolic and enzyme engineering were reviewed. The biosynthesis of saturated fatty acids (medium chain fatty acids and long chain fatty acids), bioactive fatty acids (PUFAs, oxylipins, ether lipids), and their derivatives with microbial and enzymatic catalysis were respectively summarized. Finally, synthetic biology strategies to improve fatty acids and their derivatives production through enzyme rational design, carbon metabolism flux, cofactors balance, and metabolic pathways design were discussed. The review provides references and prospects for fatty acids and their derivatives biosynthesis and industrial production.

Kluyveromyces marxianus is a non-Saccharomyces yeast that has gained importance due to its great potential to be used in the food and biotechnology industries. In general, K. marxianus is a known yeast for its ability to assimilate hexoses and pentoses; even this yeast can grow in disaccharides such as sucrose and lactose and polysaccharides such as agave fructans. Otherwise, K. marxianus is an excellent microorganism to produce metabolites of biotechnological interest, such as enzymes, ethanol, aroma compounds, organic acids, and single-cell proteins. However, several studies highlighted the metabolic trait variations among the K. marxianus strains, suggesting genetic diversity within the species that determines its metabolic functions; this diversity can be attributed to its high adaptation capacity against stressful environments. The outstanding metabolic characteristics of K. marxianus have motivated this yeast to be a study model to evaluate its easy adaptability to several environments. This chapter will discuss overview characteristics and applications of K. marxianus and recent insights into the stress response and adaptation mechanisms used by this non-Saccharomyces yeast.

The filamentous growth mode of fungi, with its modular design, facilitates fungal adaptation to stresses they encounter in diverse terrestrial and anthropogenic environments. Surface growth conditions elicit diverse morphological responses in filamentous fungi, particularly demonstrating the remarkable adaptability of mycelial systems to metal- and mineral-rich environments. These responses are coupled with fungal biogeochemical activity and can ameliorate hostile conditions. A tessellated agar tile system, mimicking natural environmental heterogeneity, revealed negative chemotropism to toxic metals, distinct extreme growth strategies, such as phalanx and guerrilla movements and transitions between them, and the formation of aggregated re-allocation structures (strands, cords, synnemata). Other systems showed intrahyphal growth, intense biomineralization, and extracellular hair-like structures. Studies on submerged mycelial growth, using the thermophilic fungus Thielavia terrestris as an example, provided mechanistic insights into the morphogenesis of two extreme forms of fungal submerged culture-pelleted and dispersed growth. It was found that the development of fungal pellets was related to fungal adaptation to unfavorable stressful conditions. The two key elements affecting morphogenesis leading to the formation of either pelleted or dispersed growth were found to be (1) a lag phase (or conidia swelling stage) as a specific period of fungal morphogenesis when a certain growth form is programmed in response to morphogenic stressors, and (2) cAMP as a secondary messenger of cell signaling, defining the implementation of the particular growth strategy. These findings can contribute to knowledge of fungal-based biotechnologies, providing a means for controllable industrial processes at both morphological and physiological levels.

This memoir takes a whimsical ride through my professional adventures, spotlighting my fungal stress research on the insect-pathogenic fungus Metarhizium robertsii, which transformed many of my wildest dreams into reality. Imagine the magic of fungi meeting science and me, a happy researcher, arriving at Utah State University ready to dive deep into studies with the legendary insect pathologist, my advisor Donald W. Roberts, and my co-advisor Anne J. Anderson. From my very first "Aha!" moment in the lab, I plunged into a vortex of discovery, turning out research like a mycelium on a mission. Who knew 18 h/day, seven days a week, could be so exhilarating? I was fueled by an insatiable curiosity, boundless creativity, and a perhaps slightly alarming level of motivation. Years later, I managed to bring my grandest vision to life: the International Symposium on Fungal Stress-ISFUS. This groundbreaking event has attracted 162 esteemed speakers from 29 countries to Brazil, proving that fungi can be both fun and globally fascinating. ISFUS is celebrating its fifth edition in 2024, a decade after its 2014 debut.

Anthropogenic activities have dramatically accelerated the release of toxic metal(loid)s into soil and water, which can be subsequently accumulated in plants and animals, threatening biodiversity, human health, and food security. Compared to physical and chemical remediation, bioremediation of metal(loid)-polluted soil using plants and/or plant symbiotic fungi is usually low-cost and environmentally friendly. Mycorrhizal fungi and endophytic fungi are two major plant fungal symbionts. Mycorrhizal fungi can immobilize metal(loid)s via constitutive mechanisms, including intracellular sequestration with vacuoles and vesicles and extracellular immobilization by cell wall components and extracellular polymeric substances such as glomalin. Mycorrhizal fungi can improve the efficacy of phytoremediation by promoting plant symplast and apoplast pathways. Endophytic fungi also use constitutive cellular components to immobilize metal(loid)s and to reduce the accumulation of metal(loid)s in plants by modifying plant physiological status. However, a specific mechanism for the removal of methylmercury pollution was recently discovered in the endophytic fungi Metarhizium, which could be acquired from bacteria via horizontal gene transfer. In contrast to mycorrhizal fungi that are obligate biotrophs, some endophytic fungi, such as Metarhizium and Trichoderma, can be massively and cost-effectively produced, so they seem to be well-placed for remediation of metal(loid)-polluted soil on a large scale.

Copper homeostasis in fungi is a tightly regulated process crucial for cellular functions. Fungi acquire copper from their environment, with transporters facilitating its uptake into the cell. Once inside, copper is utilized in various metabolic pathways, including respiration and antioxidant defense. However, excessive copper can be toxic by promoting cell damage mainly due to oxidative stress and metal displacements. Fungi employ intricate regulatory mechanisms to maintain optimal copper levels. These involve transcription factors that control the expression of genes involved in copper transport, storage, and detoxification. Additionally, chaperone proteins assist in copper trafficking within the cell, ensuring its delivery to specific targets. Furthermore, efflux pumps help remove excess copper from the cell. Altogether, these mechanisms enable fungi to balance copper levels, ensuring proper cellular function while preventing toxicity. Understanding copper homeostasis in fungi is not only essential for fungal biology but also holds implications for various applications, including biotechnology and antifungal drug development.

Filamentous entomopathogenic fungi (EPF) function as important biotic factors regulating the arthropod population in natural ecosystems and have great potential as biocontrol agents in modern agriculture. In the infection cycle, EPF undergo a plethora of physiological processes, including metabolism (e.g., cuticle hydrolysis and nutrient utilization), development (e.g., dimorphism and conidiation), stress response (e.g., oxidative and osmotic stresses), and immune evasion from the host. In-depth explorations of the mechanisms involved in the lifecycle of EPF offer excellent opportunities to increase their virulence and stability, which increases the efficacy of EPF in biocontrol programs. This review discusses the current state of knowledge relating to the biological roles and regulatory mechanisms of organelles and subcellular structures in the physiology of EPF, as well as some suggestions for future investigation.

The early postnatal period represents a critical window of time for the establishment and maturation of the human gut microbiota. The gut microbiota undergoes dramatic developmental changes during the first year of life, being influenced by a variety of external factors, with diet being a major player. Indeed, the introduction of complementary feeding provides novel nutritive substrates and triggers a shift from milk-adapted gut microbiota toward an adult-like bacterial composition, which is characterized by an enhancement in diversity and proportions of fiber-degrading bacterial genera like Ruminococcus, Prevotella, Eubacterium, and Bacteroides genera. Inadequate gut microbiota development in early life is frequently associated with concomitant and future adverse health conditions. Thus, understanding the processes that govern initial colonization and establishment of microbes in the gastrointestinal tract is of great importance. This review summarizes the actual understanding of the assembly and development of the microbial community associated with the infant gut, emphasizing the importance of mother-to-infant vertical transmission events as a fundamental arrival route for the first colonizers.

The rapid development of agriculture has led to a large amount of wastewater, which poses a great threat to environmental safety. Microalgae, with diverse species, nutritional modes and cellular status, can adapt well in agricultural wastewater and absorb nutrients and remove pollutants effectively. Besides, after treatment of agricultural wastewater, the accumulated biomass of microalgae has broad applications, such as fertilizer and animal feed. This paper reviewed the current progresses and further perspectives of microalgae-based agricultural wastewater treatment. The characteristics of agricultural wastewater have been firstly introduced; Then the microalgal strains, cultivation modes, cellular status, contaminant metabolism, cultivation systems and biomass applications of microalgae for wastewater treatment have been summarized; At last, the bottlenecks in the development of the microalgae treatment methods, as well as recommendations for optimizing the adaptability of microalgae to wastewater in terms of wastewater pretreatment, microalgae breeding, and microalgae-bacterial symbiosis systems were discussed. This review would provide references for the future developments of microalgae-based agricultural wastewater treatment.

Selenium (Se) is an essential trace element present as selenocysteine (SeCys) in selenoproteins, which have an important role in thyroid metabolism and the redox system in humans. Se deficiency affects between 500 and 1000 million people worldwide. Increasing Se intake can prevent from bacterial and viral infections. Se deficiency has been associated with cancer, Alzheimer, Parkinson, decreased thyroid function, and male infertility. Se intake depends on the food consumed which is directly related to the amount of Se in the soil as well as on its availability. Se is unevenly distributed on the earth's crust, being scarce in some regions and in excess in others. The easiest way to counteract the symptoms of Se deficiency is to enhance the Se status of the human diet. Se salts are the most toxic form of Se, while Se amino acids and Se-nanoparticles (SeNPs) are the least toxic and most bio-available forms. Some bacteria transform Se salts into these Se species. Generally accepted as safe selenized microorganisms can be directly used in the manufacture of selenized fermented and/or probiotic foods. On the other hand, plant growth-promoting bacteria and/or the SeNPs produced by them can be used to promote plant growth and produce crops enriched with Se. In this chapter we discuss bacterial Se metabolism, the effect of Se on human health, the applications of SeNPs and Se-enriched bacteria, as well as their effect on food fortification. Different strategies to counteract Se deficiency by enriching foods using sustainable strategies and their possible implications for improving human health are discussed.

This work explores astaxanthin (AXT), a valuable xanthophyll ketocarotenoid pigment with significant health benefits and diverse applications across various industries. It discusses the prevalence of synthetic AXT, and the development of natural-based alternatives derived from microorganisms such as microalgae, bacteria, and yeast. The chapter examines the potential of microbial AXT production, highlighting the advantages and challenges associated with natural AXT. Key microorganisms like Haematococcus pluvialis, Paracoccus carotinifaciens, and Phaffia rhodozyma are emphasized for their role in commercially producing this valuable ketocarotenoid. The narrative covers the complexities and opportunities in microbial AXT production, from cell structure implications to downstream processing strategies. Additionally, the chapter addresses current applications, commercialization trends, and market dynamics of natural microbial AXT, emphasizing the importance of cost-effective production, regulatory compliance, and technological advancements to reduce the market cost of the final product. As demand for natural microbial-based AXT rises, this chapter envisions a future where research, innovation, and collaboration drive sustainable and competitive microbial AXT production, fostering growth in this dynamic market.

The genome-scale metabolic network model is an effective tool for characterizing the gene-protein-response relationship in the entire metabolic pathway of an organism. By combining various algorithms, the genome-scale metabolic network model can effectively simulate the influence of a specific environment on the physiological state of cells, optimize the culture conditions of strains, and predict the targets of genetic modification to achieve targeted modification of strains. In this review, we summarize the whole process of model building, sort out the various tools that may be involved in the model building process, and explain the role of various algorithms in model analysis. In addition, we also summarized the application of GSMM in network characteristics, cell phenotypes, metabolic engineering, etc. Finally, we discuss the current challenges facing GSMM.

In Chile, as in the rest of the world, only a small fraction of the fungal diversity inhabiting the wide variety of its ecosystems is known. This diversity must hide an inestimable richness of species with interesting biotechnological potential, including fungal pigment producers. Recently, interest in filamentous fungi has increased significantly due to their importance as alternative sources of pigments and colorants that are environmentally and human health friendly. As a result, fungal pigments are gaining importance in various industrial applications, such as food, textiles, pharmaceuticals, cosmetics, etc. The increasing consumer demand for "green label" natural colorants requires the exploration of different ecosystems in search of new fungal species that are efficient producers of different pigment with a wide range of colors and ideally without the co-production of mycotoxins. However, advances are also needed in pigment production processes through fermentation, scale-up from laboratory to industrial scale, and final product formulation and marketing. In this respect, the journey is still full of challenges for scientists and entrepreneurs. This chapter describes studies on pigment-producing fungi collected in the forests of central-southern Chile. Aspects such as the exploration of potential candidates as sources of extracellular pigments, the optimization of pigment production by submerged fermentation, methods of pigment extraction and purification for subsequent chemical characterization, and formulation (by microencapsulation) for potential cosmetic applications are highlighted. This potential use is due to the outstanding bioactivity of most fungal pigments, making them interesting functional ingredients for many applications. Finally, the use of fungal pigments for textile and spalting applications is discussed.

Pathogenic fungi are widespread and cause a variety of diseases in human beings and other organisms. At present, limited classes of antifungal agents are available to treat invasive fungal diseases. With the wide use of the commercial antifungal agents, drug resistance of pathogenic fungi are continuously increasing. Therefore, exploring effective antifungal agents with novel drug targets is urgently needed to cope with the challenges that the antifungal area faces. pH homeostasis is vital for multiple cellular processes, revealing the potential for defining novel drug targets. Fungi have evolved a number of strategies to maintain a stable pH internal environment in response to rapid metabolism and a dramatically changing extracellular environment. Among them, plasma membrane H-ATPase (PMA) and vacuolar H-ATPase (V-ATPase) play a central role in the regulation of pH homeostasis system. In this chapter, we will summarize the current knowledge about pH homeostasis and its regulation mechanisms in pathogenic fungi, especially for the recent advances in PMA and V-ATPase, which would help in revealing the regulating mechanism of pH on cell growth and pathogenicity, and further designing effective drugs and identify new targets for combating fungal diseases.

The increasing need for metals leads to contaminated post-mining landscapes. At the same time, the contamination with organic, recalcitrant contamination increases. This poses a problem of reuse of large areas, often co-contaminated with both, metals, and organic pollutants. For the remediation of areas contaminated with multiple contaminants and combining many stress factors, technical solutions including groundwater treatment, where necessary, have been devised. However, this is applied to highly contaminated, small sites. The reuse of larger, co-contaminated landscapes remains a major challenge. Mycoremediation with fungi offers a good option for such areas. Fungi cope particularly well with heterogeneous conditions due to their adaptability and their large hyphal network. This chapter summarizes the advantages of basidiomycetes with a focus on wood rot fungi in terms of their ability to tolerate metals, radionuclides, and organic contaminants such as polycyclic aromatic hydrocarbons. It also shows how these fungi can reduce toxicity of contaminants to other organisms including plants to allow for restored land-use. The processes based on diverse molecular mechanisms are introduced and their use for mycoremediation is discussed.