Culture Collections as Hidden Sources of Microbial Biomolecules and Biodiversity

Abstract

The application of modern advanced techniques in molecular biology is revealing unexpectedly high levels of microbial diversity and complexity. However, the invisible loss of microbial diversity in the environment deriving, for example, from global changes and anthropogenic activities, is not really perceived. In this context, culture collections worldwide have become a valuable resource for the sustainable use of microbial diversity and its conservation. They provide pure cultures and genetic materials that are required for a number of research and teaching purposes, as well as for bioprospecting aims and their subsequent exploitation in biotechnological fields. This Special Issue has been launched with the aim of showcasing the diversity and biotechnological potential of microorganisms (e.g., Bacteria, Archaea, cyanobacteria, microalgae, fungi, yeasts, and protozoa) belonging to culture collections kept worldwide.

Public culture collections have the responsibility of maintaining and preserving microbial representatives and type strains, which can be distributed upon request for teaching and scientific purposes. On the other side, research laboratories worldwide frequently host their own microbial culture collections, often harboring microorganims from peculiar environments of different (and sometimes difficult to reach, requiring high sampling efforts) geographic regions and representing a hidden source of microbial biomolecules and biodiversity [1,2,3,4,5]. The importance of culture collections is, therefore, twofold as they represent a valuable source of biological and genetic materials for: (1) past, present, and future taxonomical research and biodiversity conservation; (2) biotechnological applications [6].

Recent advancements in the application of biomolecular techniques have profoundly changed our approach to the study of microbial communities in a wide range of environments, revealing unexpectedly high levels of microbial diversity and complexity and raising intriguing questions about how much we really know about the microbial world. It is noteworthy that culture collections certainly do not reflect overall trends in microbial diversity (and biotechnological potential) in the environment, as it is well known that only a small fraction of microorganisms can be isolated and maintained in pure cultures under laboratory conditions, which are failing to replicate essential aspects of the microbial natural environment [7]. However, while several experimental efforts are aiming for the discovery of the molecular and metabolic principles behind this recalcitrant growth, culture collections become key tools for the conservation of microbial diversity. In fact, a continuous and invisible menace, exerted by global changes and anthropogenic activities, leads to the unperceived environmental loss of the diversity of microorganisms and, therefore, of their pivotal functions in the functioning of ecosystems. At this regard, samples from habitats that could harbor undiscovered microbial diversity and risk extinction or being irreparably altered, due to human and natural perturbations, should be a primary focus of culture collections [8,9,10]. Microorganisms (both prokaryotes and eukaryotes) also possess high biotechnological relevance for the synthesis of molecules with antimicrobial, antioxidant, or antitumor activities for the production of bioenergy and compounds (e.g., extracellular polymeric substances, enzymes, polyunsaturated fatty acids) to be applied in industrial and agricultural applications, as well as for eco-friendly use in the bioremediation field (e.g., the removal of recalcitrant compounds). All such applications depend upon the availability of viable microbial cultures [11].

For these reasons, as guest editors, we hope that this proposed Special Issue provides novel insights of broad interest and highlights the great importance and role of often untapped culture collections for the conservation and sustainable use of microbial diversity. We are confident that this Special Issue will not only show the research activities linked to microbial preservation, but will also inspire researchers to further explore culture collections for possible and yet untapped applications.