The importance of insects for angiosperm pollination is widely recognized. In fact, approximately 90% of all plant species benefit from animal-mediated pollination. However, only recently, a third part player in this story has been properly acknowledged. Microorganisms inhabiting floral nectar, among which yeasts have a prominent role, can ferment glucose, fructose, sucrose, and/or other carbon sources in this habitat. As a result of their metabolism, nectar yeasts produce diverse volatile organic compounds (VOCs) and other valuable metabolites. Notably, some VOCs of yeast origin can influence insects’ foraging behavior, e.g., by attracting them to flowers (although repelling effects have also been reported). Moreover, when insects feed on nectar, they also ingest yeast cells, which provide them with nutrients and protect them from pathogenic microorganisms. In return, insects serve yeasts as transportation and a safer habitat during winter when floral nectar is absent. From the plant’s point of view, the result is flowers being pollinated. From humanity’s perspective, this ecological relationship may also be highly profitable. Therefore, prospecting nectar-inhabiting yeasts for VOC production is of major biotechnological interest. Substances such as acetaldehyde, ethyl acetate, ethyl butyrate, and isobutanol have been reported in yeast volatomes, and they account for a global market of approximately USD 15 billion. In this scenario, the present review addresses the ecological, environmental, and biotechnological outlooks of this three-party mutualism, aiming to encourage researchers worldwide to dig into this field.

Yeasts are the most used microorganisms for biotechnological purposes. Although they have been mainly recognized for their application in the beverage and bioethanol industries, these microorganisms can be efficiently employed in pharmaceutical and food production companies. In these industrial sectors, yeasts are highly desirable for their capacity to produce bioactive compounds from simple substrates, including wastes. In this review, we present the state of the art of bioactive compound production in microbial cell factories and analyze the avenues to increase the productivity of these molecules, which benefit human and environmental health. The article addresses their vast biological activities, from preventing to treating human diseases and from pre to postharvest control on agroindustrial streams. Furthermore, different yeast species, genetically engineered or not, are herein presented not only as biofactories of the referred to compounds but also as their targets. This comprehensive analysis of the literature points out the significant roles of biodiversity, bioprospection, and genome editing tools on the microbial production of bioactive compounds and reveals the value of these approaches from the one health perspective.

The literature is full of studies reporting environmental and health issues related to using traditional pesticides in food production and storage. Fortunately, alternatives have arisen in the last few decades, showing that organic agriculture is possible and economically feasible. And in this scenario, fungi may be helpful. In the natural environment, when associated with plants, these microorganisms offer plant-growth-promoting molecules, facilitate plant nutrient uptake, and antagonize phytopathogens. It is true that fungi can also be phytopathogenic, but even they can benefit agriculture in some way—since pathogenicity is species-specific, these fungi are shown to be useful against weeds (as bioherbicides). Finally, plant-associated yeasts and molds are natural biofactories, and the metabolites they produce while dwelling in leaves, flowers, roots, or the rhizosphere have the potential to be employed in different industrial activities. By addressing all these subjects, this manuscript comprehensively reviews the biotechnological uses of plant-associated fungi and, in addition, aims to sensitize academics, researchers, and investors to new alternatives for healthier and more environmentally friendly production processes.

Brazil has made significant progress in ethanol production from sugarcane juice. However, in terms of water, food, and environmental safety, this production can be optimized by replacing raw food with agricultural waste, giving rise to second-generation ethanol (2G). Among these biomasses, coconut residue stands out in tropical countries like Brazil. This study aimed to fractionate coconut husk through alkaline pretreatment with calcium hydroxide (20% w/w) followed by enzymatic hydrolysis with Novozymes^TM Ctec2 and Htec2. The conversion efficiency of polysaccharides into monosaccharides was 19.3% for cellulose and 7.3% for hemicellulose. The inhibitors acetic acid (∼3.0 g/L) and formic acid (∼0.8 g/L) were also observed in the hydrolysate, to which 17.5 g/L NaCl was added to evaluate yeast cells under salt stress. The wild strain Wickerhamomyces sp. UFFS-CE-3.1.2 and the industrial yeast Saccharomyces cerevisiae PE-2 were inoculated into this non-detoxified high-salt hydrolysate and analyzed through a Central Composite Design (CCD). The independent variables were the effects of pH and temperature on yeast metabolism. Assuming cellular growth and sugar consumption as responses to the experimental design, pH of 7.0 and temperature of 40°C were defined as the best cultivation conditions for subsequent fermentation kinetics. As a result, the wild yeast showed the highest biomass production, but it did not produce ethanol. In contrast, the industrial strain fermented glucose, displaying an ethanol yield of 0.24 g_ethanol/g_sugar. Thus, coconut husk can be promising biomass for 2G ethanol production, even though it requires pretreatment and hydrolysis optimization to increase sugar concentration and reduce inhibitors in the hydrolysate.