Nutritional control of antibiotic production by Streptomyces platensis MA7327: importance of l-aspartic acid

Abstract

Streptomyces platensis MA7327 is a bacterium producing interesting antibiotics, which act by the novel mechanism of inhibiting fatty acid biosynthesis. The antibiotics produced by this actinomycete are platensimycin and platencin plus some minor related antibiotics. Platensimycin and platencin have activity against antibiotic-resistant bacteria such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus; they also lack toxicity in animal models. Platensimycin also has activity against diabetes in a mouse model. We have been interested in studying the effects of primary metabolites on production of these antibiotics in our chemically defined production medium. In the present work, we tested 32 primary metabolites for their effect. They included 20 amino acids, 7 vitamins and 5 nucleic acid derivatives. Of these, only L-aspartic acid showed stimulation of antibiotic production. We conclude that the stimulatory effect of aspartic acid is due to its role as a precursor involved in the biosynthesis of aspartate-4-semialdehyde, which is the starting point for the biosynthesis of the 3-amino-2,4-dihydroxy benzoic acid portion of the platensimycin molecule.

Bioprocessing strategies for cost-effective large-scale biogenic synthesis of nano-MgO from endophytic Streptomyces coelicolor strain E72 as an anti-multidrug-resistant pathogens agent

“…Evaluation, selection, and optimization of the culturing media are essential steps that prior the semi-pilot or pilot production plans for biomass production and hence for bioactive metabolite production 65 . Advanced statistical medium optimization technique has been proved as the effective optimization strategies that might be useful for the overproduction of many bioactive metabolites in the large scale fermentation process 1 . The successful industrial bioprocessing strategies depend on the product cost that could be reduced by using cheaper carbon/nitrogen sources (growth inducer) and/or by increasing the bioactive metabolites productivity and reduce the loss of unused substrate 66 .…”

“…There are studies recorded that the specific metabolites production doubled when nitrate was replaced with ammonium, and the biomass yield increased many times 46 , 48 , 68 , 70 . Most of the growth media that reported earlier contained a mix of complex organic and/or inorganic nitrogen sources, viz the proficient Streptomyces medium cannot be generalized 1 , 47 , 67 , 74 . Finally, the endophytic Streptomyces coelicolor strain E72 cultivated by using cost-effective industrial fermentation medium (inexpensive substrates).…”

“…High functional bioactive compounds yielding through cell fractionations were checked (extracellularly and intracellularly). After fermentation step, the broth culture was centrifuged at 14,000 rpm for 20 min to separate the supernatant and the pellet 1 , 25 , 43 , 49 . To extract the extracellular metabolites equal volume of ethyl acetate was added to the supernatant and the mixture was kept for overnight in a rotary shaker.…”

“…There are different human pathogenic species resist all known antibiotic classes and organic antimicrobial agents (bacteriocins and enzymes, etc), so the pharmaceutical companies and the researchers planned to emerge up from this problem by discovering and developing other antimicrobial agents 1 – 4 . Synthesized nanoparticles recognized as effective antimicrobial agents used in different biomedical applications due to their morphological structure, stability, and surface properties 5 – 10 .…”

Systematic optimization for production of the anti‐MRSA antibiotics WAP‐8294A in an engineered strain of Lysobacter enzymogenes

“…For qualitative analysis, a 20 ll aliquot of each extracts was analysed by LC-MS as described previously (Yu et al, 2018). For semi-quantitative analysis, the inhibition zone method was used (Delgado et al, 2005;Falzone et al, 2017). Bacillus subtilis was used as the indicator microorganism for the antibacterial activity of WAP-8294A compounds, and the size of inhibition zones on plates was used as a measurement of WAP-8294A concentration, based on a standard curve generated from a serial dilution of vancomycin as a function of the size of inhibition zones.…”