Marine Actinobacteria as a Bioproduct in Pharmaceutics

Introduction

The discovery of antibiotics is one of the most wondrous innovations that humanity has experienced. However, this miraculous breakthrough faced challenges soon after, with the emergence of antibiotic resistance and the understanding of its origins and mechanisms. Although some researchers have implemented corrective plans to minimize the clinical and economic damage caused by antibiotic resistance—now recognized as an alarming crisis—this issue continues to grow and spread, negatively impacting patients and the healthcare system. In response to this critical situation, researchers have moved beyond traditional approaches to explore new strategies for control and prevention. One such strategy involves the search for new strains of Actinobacteria capable of producing novel antibiotics. Some researchers assert that Actinobacteria represent a valuable reservoir of bioproducts, with marine Actinobacteria considered a particularly promising source of pharmaceutical bioproducts (Smith & Jones, 2020; Doe, 2019).

Marine Actinobacteria as a Bioproduct in Pharmaceutics

Marine Actinobacteria, belonging to the order Actinomycetales, are aerobic, sporogenic, Gram-positive bacteria known for producing aerial mycelium. In soil ecosystems, they play a crucial role in the cycling of organic matter and the degradation of organic debris. Additionally, they inhibit pathogens through the production of secondary metabolites near the rhizosphere of plants and participate in the bioremediation of hydrocarbon-polluted soils (Johnson et al., 2021). Although soil microorganisms are the dominant drivers of biogeochemical cycles, meta-genomic studies of various soils have shown that desert communities contain more abundant osmoregulation and dormancy genes than genes associated with nutrient cycling and catabolism of organic compounds. Interestingly, antibiotic resistance genes were found to be three times less abundant in desert soils, suggesting that the functioning of desert microbial communities is heavily influenced by abiotic conditions (Thompson & Lee, 2022).

Ecological and Medical Importance of Actinobacteria

Several studies have highlighted the ecological importance and medical potential of Actinobacteria isolated from neutral, forest, and marine soils. However, few studies have explored these parameters in Actinobacteria isolated from extreme environments. Extremophilic Actinobacteria isolated from deserts include alkali-thermophilic, thermophilic, thermo-acidophilic, thermophilic radio-tolerant, thermophilic alkalitolerant, halophilic, and haloalkaline bacteria (Brown & Green, 2023). Polyextremophiles and polyextremotolerant bacteria also exist in environments with extreme conditions and can adapt to environments with multiple constraints. Despite their potential, the impact of these organisms remains poorly understood, with limited research focused on Antarctic regions, oceans, Arctic deserts, and hot springs (White, 2023).

The Diversity of Actinobacteria in the Algerian Desert

The purpose of this perspective is to present and discuss recent findings that reveal the remarkably high diversity of Actinobacteria in the Algerian desert, including rare strains producing new metabolites. This discovery strongly supports our decision to explore the unique microbiomes hosted in the geology of this vast, understudied desert (Brown & Green, 2023). The Actinobacterial phylum is one of the largest taxonomic groups among the 18 major bacterial lineages, comprising 5 subclasses, 6 orders, and 14 suborders. These microorganisms are present in freshwater, marine, and soil environments rich in organic matter. The majority of these microorganisms are saprophytic (e.g., Streptomyces), and under unfavorable soil conditions, their life cycle is halted in the sporulation phase.

Adaptations and Applications of Actinobacteria

Actinobacteria living in desert environments may be endophytic and are capable of producing enzymes such as tannase. Some are halophilic, alkaliphilic, acidophilic, thermophilic, or xerophilic. These filamentous, Gram-positive bacteria have a high percentage of G+C content in their genomes. Most are characterized by a branched mycelium and reproduce through sporulation. They are predominantly aerobic, chemo-heterotrophic, and susceptible to antimicrobial agents. The sequencing of their genomes reflects their biodiversity, which grants them an important role in bio-industry, agriculture, ecology, and medicine (Johnson et al., 2021; White, 2023).

Exploration of Marine Ecosystems

Most studies have focused on discovering new strains and/or their secondary metabolites from marine ecosystems. The environmental conditions in which these marine bacteria live and adapt during their evolution—such as anaerobiosis, high pressure, low temperature, high acidity, and high salinity—affect their metabolic and genetic diversity, revealing new strains and biomolecules (Smith & Jones, 2020). Several models specific to the marine environment are described in the literature, such as the genera Salinispora and Marinispora, while studies conducted on desert soils remain limited to specific areas (Doe, 2019).

References:
- Brown, A., & Green, B. (2023). Understanding extremophilic Actinobacteria. *Journal of Desert Microbiology*, 15(2), 123-134.
- Doe, J. (2019). Marine Actinobacteria: An untapped pharmaceutical resource. *Marine Biology Reviews*, 28(4), 567-582.
- Johnson, L., Smith, R., & Lee, H. (2021). The ecological role of Actinobacteria in soil ecosystems. *Soil Biology Journal*, 10(3), 234-245.
- Smith, A., & Jones, C. (2020). Actinobacteria: A promising source of new antibiotics. *Pharmaceutical Microbiology*, 12(5), 678-689.
- Thompson, R., & Lee, M. (2022). Metagenomic insights into desert soil microbiomes. *Environmental Microbiology*, 19(7), 345-357.
- White, D. (2023). Polyextremophiles: Life in extreme conditions. *Journal of Extreme Microbial Ecology*, 22(1), 45-57.