# Cold-Adapted Fungi: Goldmine of Biomolecules Applicable in Industry
## 4 Biotechnological Application of Psychrophilic Fungi in Food and Agriculture
### Biosurfactants  
Other bioactive molecules produced by psychrophilic and psychotrophic fungi are biosurfactants. These are amphiphilic compounds that reduce the surface and interfacial tension between liquids, solids, and gases. These biomolecules are distinguished by a lower mass than EPSs and are predominantly composed of sugars, amino acids, fatty acids, and carboxylic acids. Structurally, they are highly diverse compounds, but the most commonly identified include glycolipids (rhammolipids, sophorolipids, trehalose lipids, and mannasylerlythritol lipids), lipoproteins (surfactin, iturin, fengycin, viscosin), phospholipids, fatty acids, and neutral lipids [49]. In their natural habitats, it is hypothesized that they facilitate the uptake of highly hydrophobic, insoluble substrates and play a role in regulating biofilm structure.  
Biosurfactants are produced by many extremophilic fungi, including cold-loving filamentous fungi and yeasts. Yeast species belonging to the genus _Rhodotorula_, commonly found in polar regions and glaciers, have the ability to produce exceptionally high levels of sophorolipids. Biosurfactants derived from this genus have already been commercialized; however, expanding the collection to incorporate additional extremophilic producers represents a notable advancement in the field of biosurfactant research [139]. One of the most valuable biosurfactant producers is the psychrophilic yeast _Moesziomyes antarcticus_ (formerly known as _Pseudozyma_/_Candida antarctica_). This yeast is known to produce molecules of industrial importance, including glycolipid biosurfactants of the type mannasylerythtitol lipids (MELs: MEL-A, MEL-B, MEL-C), which possess ice-recrystallization inhibitory activity. MEL-A has been demonstrated to exhibit high ice-aggregation activity [155]. The structure and type of biosurfactant produced influence its properties and, consequently, its applicability [156].  
It is, therefore, important to identify new microbial sources of these biomolecules. In the previous year, new Antarctic isolates of filamentous fungi with high production potential have been discovered, including _Antractomyces psychrotrophicus_, _Pseudogymoascus_ sp., _Cosmospora_ sp., _Thelebolus_ sp., and _Rampea ozimecii_[65; 157].  
Biosurfactants possess a number of advantageous characteristics. They are produced by microorganisms from renewable materials, exist in a multitude of chemical varieties, and can therefore be employed in a diverse range of applications. Additionally, they are active at very low concentrations and are biocompatible, making them suitable for release into the environment. Biosurfactants are regarded as a potential environmentally friendly substitute for chemical surfactants in a vast array of commercial products. Furthermore, they have been demonstrated to possess antibacterial and antifungal activities, which will undoubtedly enrich the value of the product [49; 139]. The multiplicity of these features serves to enhance their extensive industrial applicability, including within the fields of food technology and agriculture (Figure 5).  
Furthermore, the application of low-temperature biosurfactants will ensure the continued efficiency of energy processes, thereby reducing energy consumption and costs while also limiting environmental impact. As the requirements for biotechnology products become increasingly rigorous, the energy factor will assume great significance in the modernization of entire production lines [139].