Modeling and Statistical Optimization of Culture Conditions for Improvement of Antifungal Compounds Production by Streptomyces albidoflavus S19 Strain of Wastewater Origin

Enhancement of Streptomyces thinghirensis WAE1 for production of bioactive metabolites under different optimization strategies

Isolation of novel bioactive metabolites from Streptomyces strains is a promising source for drug discovery. However, conventional screening approaches have limitations in identifying new leads due to redundant discoveries. Optimization of culture conditions is important but traditionally optimized one factor at a time, failing to consider interactions. This study addressed these gaps by enhancing metabolite production from Streptomyces thinghirensis WAE1 through statistical optimization. Various chemical and physical factors impacting metabolite production were identified. Response surface methodology with a central composite design was applied to optimize significant factors like carbon source, nitrogen source, inoculum size, pH, temperature and incubation period. This optimized production against Streptococcus pneumoniae, increasing antibacterial activity by 74.92%. Gas chromatography-mass spectrometry revealed 19 bioactive compounds, including 1,25-dihydroxyvitamin D3 inhibiting cell wall development. This highlights S. thinghirensis WAE1's potential as a bioresource and emphasizes studying metabolite production from novel Streptomyces strains to discover new antibacterial drugs.

Antimicrobial and antinematicidal metabolites from Streptomyces cuspidosporus strain SA4 against selected pathogenic bacteria, fungi and nematode

The exploration of novel therapeutic agents and other bioactive secondary metabolite from Streptomyces species, for possible agricultural farming, pharmaceutical and industrialized applications, has been, and still is, essential. The existing studies were aimed with biologically potential Streptomyces species and its antagonistic activity against dreadful microorganisms. Totally, morphological three different actinomycetes were selected from the fertile agricultural lands. Among the three, the isolate SA4 exhibited significant antimicrobial and anti-nematicidal activity towards selected microbial pathogens such as E Escherichia coli, Klebsiella pneumonia, Staphylococcus aureus, Salmonella typhi, Bacillus subtilis, Proteus vulgaris, Shigella flexineri, Candida albicans, and Fusarium sp. The prospective strain SA4 was identified as Streptomyces cuspidosporus. The isolate SA4 optimized for secondary metabolites production with International Streptomyces project 4 (ISP 4) medium, pH 7.0 at 37 °C for 14 days. Gas Chromatography-Mass spectrometry (GCMS) analysis of strain SA4 bioactive extract publicized the existence of 1,2-Benzenedicarboxylic acid, bis(2-Methylpropyl) ester compound and occupied by high peak area and its possessed significant biological properties.

Actinobacteria Derived from Algerian Ecosystems as a Prominent Source of Antimicrobial Molecules

Actinobacteria, in particular "rare actinobacteria" isolated from extreme ecosystems, remain the most inexhaustible source of novel antimicrobials, offering a chance to discover new bioactive metabolites. This is the first overview on actinobacteria isolated in Algeria since 2002 to date with the aim to present their potential in producing bioactive secondary metabolites. Twenty-nine new species and one novel genus have been isolated, mainly from the Saharan soil and palm groves, where 37.93% of the most abundant genera belong to Saccharothrix and Actinopolyspora. Several of these strains were found to produce antibiotics and antifungal metabolites, including 17 new molecules among the 50 structures reported, and some of these antibacterial metabolites have shown interesting antitumor activities. A series of approaches used to enhance the production of bioactive compounds is also presented as the manipulation of culture media by both classical methods and modeling designs through statistical strategies and the associations with diverse organisms and strains. Focusing on the Algerian natural sources of antimicrobial metabolites, this work is a representative example of the potential of a closely combined study on biology and chemistry of natural products.