Actinobacteria: A Renewable Source of Bioactive Molecules with Medical, Industrial and Pharmacological Importance

The Actinobacteria receive much attention, since they produce a wide variety of metabolites, including
antibiotics, antitumor agents, antioxidant molecules and enzyme inhibitors. These bacteria can be
found in various habitats, including soil, ocean, extreme environments, mangrove, lichen, plants, and
animals. The classification of Actinobacteria based upon the morphological observation, physiological
and biochemical characteristics is not enough to differentiate the genera of this phylum. Following, a
complementary identification is performed based on the distribution of specific constituents of the
cellular wall, such as diaminopimelic acid and carbohydrates. With the advent of molecular biology,
the identification of genera and species became more reliable. The screening of microbial natural
products has become an important route to discover new bioactive compounds in order to develop
new therapeutic agents. Actinobacteria remains one of the leading producers of biopharmaceuticals;
endophytic Actinobacteria also yield secondary metabolites with wide range of biological activity. This
review focuses on gathering relevant information on identification, classification, chemical diversity of
Actinobacteria, as well as reveals some biotechnological applications of these bacteria. Actinobacteria
are microorganisms widely distributed in nature, inhabiting mainly soil, and plants. These prokaryotes
are broadly responsible for the production of various metabolites commercially available, such as
antibiotics, antifungal compounds, enzymes, and chemotherapeutic agents. Endophytic
Actinobacteria also produce active substances, and have important functions in the development of
plants with agro-industrial interest, as well as in research efforts against multidrug-resistant bacteria,
in order to find new effective compounds that can be used in clinical routine. This review provides
data with a focus on spreading the importance of these microorganisms, as well as turns the attention
to the fact that more studies are necessary for application of these Actinobacteria as innovative
biotechnological tools.