Use of sheep myeloid antimicrobial peptide (SMAP-18) and siderophore Pyochelin for mitigation of aerospace fuel-degrading microbes

• Published in: International biodeterioration & biodegradation 2025-01, Vol.196, p.105943, Article 105943
• Main Authors: Barry Schroeder, Amanda L., Radwan, Osman, Ruiz, Oscar N., Gunasekera, Thusitha S., Hoffmann, Andrea
• Format: Article
• Language: English
• Subjects: antimicrobial peptides; antimicrobial properties; bacterial growth; biodegradation; biofouling; fuels; Gordonia sp; Hydrocarbon degrading microorganisms; Identification of new antimicrobials; infrastructure; Jet fuel biocontamination; liquids; microbial contamination; minimum inhibitory concentration; Novel bacteriocides; Pseudomonas putida; Pyochelin; sheep; Sheep myeloid antimicrobial peptide (SMAP-18); siderophores; yeasts
• ISSN: 0964-8305
• DOI: 10.1016/j.ibiod.2024.105943

Sustainment of aviation fuel infrastructure is expensive and requires frequent testing for hydrocarbon-degrading microbes to assure safeguarding of fuel quality and engineering systems. Microbial contaminants in Jet fuel, including Gram-positive and Gram-negative bacteria, yeast, and filamentous fungi, necessitate early action to prevent biofouling and biocorrosion. Recent studies have identified two novel antimicrobial agents, the sheep myeloid antimicrobial peptide SMAP-18 and the iron chelating siderophore, Pyochelin with potential suitable antimicrobial properties for jet fuel sustainment. This study evaluates the antimicrobial activity of SMAP-18 and Pyochelin in specialized antimicrobial assays including liquid and fuel-culture minimum inhibitory concentration (MIC) testing, small-scale (25 mL) and large-scale (1 L) Jet A fuel microbial consortium cultures. The results show that repetitive dosing of combined SMAP-18 and Pyochelin is bactericidal and able to control bio-contaminant progression of Gram-positive Gordonia sp., and Gram-negative Pseudomonas putida bacteria in jet fuel. Moreover, the synergy observed between SMAP-18 and Pyochelin highlights their complementary mechanisms of action against microbial targets resulting in complete elimination of bacterial growth with a −7.9 log fold reduction through day 24. Antimicrobial Action of SMAP-18 and Pyochelin Synergistic Treatment on Fuel Microbial Consortia. A) Microbial contamination and biofilm formation in jet fuel represents a challenge to the aerospace industry. Image shows jet fuel culture with fuel phase, intermediate biofilm and underlying water bottom. Fuel and water phase separation is marked by red line. B) Synergistic treatment with antimicrobial peptide SMAP-18 and siderophore compound Pyochelin in jet fuel microbial consortium. Images show control versus SMAP-18 and Pyochelin combined antimicrobial treatment following 10 days culture, and example of colony forming unit determination from culture plating with mixed microbes Y. lipolytica and P. putida. [Display omitted] •Identification of Proteobacterial and Actinobacterial biocides for Jet Fuel Sustainment.•Antimicrobial peptides SMAP-18 and siderophore Pyochelin inhibit bacterial growth in liquid medium and in jet fuel culture.•The SMAP-18 and Pyochelin combinatorial treatment seems to be the most suitable for bacteriostatic inhibition of Gordonia sp.