Secondary metabolites and biodiversity of actinomycetes

Abstract

Background The ability to produce microbial bioactive compounds makes actinobacteria one of the most explored microbes among prokaryotes. The secondary metabolites of actinobacteria are known for their role in various physiological, cellular, and biological processes. Main body Actinomycetes are widely distributed in natural ecosystem habitats such as soil, rhizosphere soil, actinmycorrhizal plants, hypersaline soil, limestone, freshwater, marine, sponges, volcanic cave—hot spot, desert, air, insects gut, earthworm castings, goat feces, and endophytic actinomycetes. The most important features of microbial bioactive compounds are that they have specific microbial producers: their diverse bioactivities and their unique chemical structures. Actinomycetes represent a source of biologically active secondary metabolites like antibiotics, biopesticide agents, plant growth hormones, antitumor compounds, antiviral agents, pharmacological compounds, pigments, enzymes, enzyme inhibitors, anti-inflammatory compounds, single-cell protein feed, and biosurfactant. Short conclusions Further highlight that compounds derived from actinobacteria can be applied in a wide range of industrial applications in biomedicines and the ecological habitat is under-explored and yet to be investigated for unknown, rare actinomycetes diversity.

Recent Antimicrobial Responses of Halophilic Microbes in Clinical Pathogens

“…Ultimately, the principal phylum responsible for the inhibition of clinical pathogens are Actinobacteria, which are available as frequent isolates from solar salterns, sea floor sediments, and mangroves. The predominant genera here are Streptomyces and Nocardiopsis [26,28,29]. Aside from the Actinomycetes, other genera, such as Bacillus (Bacillus sp.…”

“…Both halophiles and halotolerants produce antimicrobials at optimal culture conditions, such as the halophilic Actinomycetes sp., halophilic Kocuria sp., and halotolerant Micromonospora sp., which secrete antibacterial compounds against Staphylococcus citreus, Staphylococcus aureus, and Vibrio cholera [25]. Even some antifungal activities were provided by hypersaline actinomycete genera against Aspergillus niger, Cryptococcus sp., and Fusarium solani [26]. Antimicrobials derived from Microbacterium oxydans and Streptomyces fradiae of foreshore soils showed broad-spectrum action against P. aeruginosa, S. typhi, Micrococcus luteus, C. albicans, and Colletotrichum gloeosporioide [27].…”

Antimicrobial Food Packaging Based on Prodigiosin-Incorporated Double-Layered Bacterial Cellulose and Chitosan Composites

“…Over the last years, efforts have been made to reduce production costs, by replacing synthetic media constituents with alternative feedstock, which would be a suitable strategy to obtain cost-effective bioresources, such as BC and PG pigment [48,99]. Moreover, the path for the cost-effective production of bacterial pigments may be the identification of new bacterial sources, such as actinobacteria, able to produce bioactive pigments that might diffuse into the medium, which ultimately facilitates pigment recovery and reduces the overall cost of the downstream process [100].…”

Actinobacteria From Desert: Diversity and Biotechnological Applications

“…Members of some rare actinobacteria are comparable to their Streptomyces neighbors in term of bioactive compound production. These prolific rare actinobacterial species belong to the families of Micromonosporaceae (1,061), Mycobacteriaceae (483), Pseudonocardiaceae (327), Streptosporangiaceae (154), and Thermomonosporaceae (633) ( Selim et al, 2021 ). Other unclassified species with reported ability to produce bioactive metabolites belonged to the genera of Actinosporangium (30), Alkalomyces (1), Catellatopsora (1), Elaktomyces (3), Erythrosporangium (1), Excelsospora (3), Frankia (7), Kitasatoa (5), Microechinospora (1), Microellobosporia (11), Salinospora (1), Sebekia (3), Streptoplanospora (1), Synnenomyces (4), Waksmania (3), and Westerdykella (6) ( Selim et al, 2021 ).…”

“…These prolific rare actinobacterial species belong to the families of Micromonosporaceae (1,061), Mycobacteriaceae (483), Pseudonocardiaceae (327), Streptosporangiaceae (154), and Thermomonosporaceae (633) ( Selim et al, 2021 ). Other unclassified species with reported ability to produce bioactive metabolites belonged to the genera of Actinosporangium (30), Alkalomyces (1), Catellatopsora (1), Elaktomyces (3), Erythrosporangium (1), Excelsospora (3), Frankia (7), Kitasatoa (5), Microechinospora (1), Microellobosporia (11), Salinospora (1), Sebekia (3), Streptoplanospora (1), Synnenomyces (4), Waksmania (3), and Westerdykella (6) ( Selim et al, 2021 ). Based on the metagenomic analyses and rank abundance analyses, diverse rare actinobacterial taxa are detected in the desert with their population significantly higher (over 34%) than that of validly published taxa ( Idris et al, 2017a ).…”