Marine Actinobacteria as a Bioproduct in Pharmaceutics

The discovery of antibiotics is one of the wonders innovations that humanity has experienced, but this light miracle died out just after the appearance of antibiotic resistance and the understanding of these origins and mechanisms. Although some authors have implemented corrective plans to minimize the clinical and economic damage caused by the antibiotic resistance known today as an alarming crisis, the latter continues to grow and spread by implanting these different negative impacts on the patient and the health system. Faced with this alarming situation, the researchers left the classical platforms to find new strategies for control and prevention. The research for new strains of Actinobacteria producing new antibiotics is one of the strategies, as some authors claim that this group of Actinobacteria is a bioproduct deposit, moreover marine Actinobacteria are also considered a good source of pharmaceutical bioproducts.

These bacteria belonging to the order of actinomycetales are aerobic, sporogenic, Gram positive and producing aerial mycelium, in the soil they play a role in the cycling of organic matter and the degradation of organic debris, inhibit pathogens by production of secondary metabolites near the rhizosphere of plants and participates in the bio-decontamination of soils polluted by hydrocarbons. Although soil microorganisms are the dominant animators of biogeochemical cycles, the meta-genomic study of different soils has shown that desert communities have more abundant osmoregulation and dormancy genes than genes associated with nutrient cycling and catabolism of organic compounds. Antibiotic resistance genes were three times less abundant in desert soils suggesting that the functioning of desert microbial communities is related to abiotic conditions.

Several studies have revealed the role, the ecological importance and the medical interest of Actinobacteria isolated from neutral soils, forest, and marine, but few studies have illustrated these parameters in actinobacteria isolated from extreme environments. These extremophilic actinobacteria isolated from the desert correspond to alkali-thermophilic, thermophilic, thermo-acidophilic, thermophilic radio-tolerant, thermophilic alkalitolerant, halophilic and haloalkaline bacteria. Polyextremophile and polyextremotolerantalso exist in environments with extreme conditions and can adapt to environments with multiple constraints, their impact is poorly illustrated on some limited work on the Antarctic regions, the oceans, Arctic deserts and hot springs.

The purpose of this perspective is to join and expose the very recent results revealing the remarkably high diversity of actinobacteria in the Algerian desert including rare strains producing new metabolites, a conclusion that strongly resonates with our decision to explore the unique microbiomes hosted in the geology of this vast desert illustrated in this perceptive and which is really little studied.

The actinobacterial phylum is one of the largest taxonomic ranks among the 18 major lineages known in the field of bacteria, including 5 subclass, 6 orders and 14 suborders. They are present in fresh water, marine, and abundant in soils rich in organic matter. The majority of these microorganisms are saprophyte (Streptomyces) and under unfavorable soil conditions, their life cycle is blocked in the sporulation phase.

These microorganisms also living in desert, may be endophytic and even produce certain enzymes such as tannase, some are halophilic, alkaliphilic, acidophilic, thermophilic, xerophilic. These are filamentous, Gram+ bacteria with a high percentage of G+C in their genome, most are characterized by a branched mycelium and reproduce by sporulation, the majority are aerobic, chemo-heterotrophic and susceptible to antimicrobial agents. The sequencing of their genomes reflects their biodiversity which gives them an important place in the fields of bio-industry, agriculture, ecology and medicine.

Most of the studies have been oriented towards finding new strains and/or their secondary metabolites from marine ecosystems. Due to the environmental conditions that these marine bacteria live and adapted during their evolution, citing, for example, anaerobiosis, high pressure, low temperature, high acidity and high salinity, which affect the metabolic and genetic diversity disclosing new strains and biomolecules. Several models specific to the marine environment are described in the literature as the genus Salinispora and Marinispora, while studies carried out on desert soils are limited to specific areas.