A non-polyenic antifungal produced by a Streptomyces yatensis strain isolated from Mellah Lake in El Kala, North-East of Algeria

Diving into freshwater microbial metabolites: Pioneering research and future prospects

In practically every facet of life, especially nutrition, agriculture, and healthcare, microorganisms offer a prospective origin for abundant natural substances and products. Among these microorganisms, bacteria also possess the capability to rapidly acclimate to diverse environments, utilize varied resources, and effectively respond to environmental fluctuations, including those influenced by human activities like pollution and climate change. The ever-changing environment of freshwater bodies influences bacterial communities, offering opportunities for improving health and environmental conservation that remain unexplored. Herein, the study discusses the bacterial taxa along with specialised metabolites with antioxidant, antibacterial, and anticancer activity that have been identified from freshwater environments, thus achieving Sustainable Development Goals addressing health and wellbeing (SDG-3), economic growth (SDG-8) along with industrial development (SDG-9). The present review is intended as a compendium for research teams working in the fields of medicinal chemistry, organic chemistry, clinical research, and natural product chemistry.

Strepolyketide D, a new SEK15-derived polyketide compound from salt-lake-derived Streptomyces sp. DBC5

A new SEK15-derived polyketide compound, strepolyketide D (1), was isolated from salt-lake-derived Streptomyces sp. DBC5, together with two known analogues (2-3). Their structures were elucidated based on spectroscopic analysis of IR, MS, 1 D and 2 D NMR. Compound 2 elicited moderate antioxidation with IC₅₀ value of 39.26 μg/ml. The results of the study revealed that salt-lake actinomycetes of Lake Dabancheng appear to have immense potential as a source of polyketide compounds.

Taxonomic Characterizations of Soil Streptomyces cavourensis DW102 and Its Activity against Fungal Pathogens

Background:

Streptomyces spp. are soil bacteria that have commercial value from which numerous secondary metabolites such as antifungal compounds have been derived. There is growing concern that antifungal resistance is on the rise, and soil Streptomyces from various geographical places might produce novel antifungal molecules. The aim of this study was to characterize and identify the actinomycetes strain namely Streptomyces isolate DW102, and to evaluate its antimicrobial activity against nosocomial fungal pathogens.

Materials and Methods:

Streptomyces isolate DW102 was identified based on morphological, cultural, physiological, and biochemical properties, together with 16S rRNA sequence. Its antifungal activity was determined by agar well-diffusion assays.

Results:

The isolate DW102 phenotypic and molecular characterization was identified as Streptomyces cavourensis DW102 and sequencing results were deposited in GenBank under accession number MK508855. Furthermore, the fermented broth of Streptomyces isolate DW102 inhibited the growth of Aspergillus niger and Candida albicans in vitro.

Conclusions:

Phenotypic, molecular, and phylogenetic analysis of DW102 identified the strain to be S. cavourensis. The antifungal assay showed that DW102 fermentation broth was active against both C. albicans and A. niger in vitro. Further studies are required to use the Streptomyces isolate DW102 as a promising source for the development of antifungal drugs.