Characterization of medium chain length (R)-3-hydroxycarboxylic acids produced by Streptomyces sp. JM3 and the evaluation of their antimicrobial properties.
(R)-3-Hydroxycarboxylic acids, chiral enantiomers of bacterial polyhydroxyalkanoates (PHA), may be valuable synthons for the production of numerous industrial materials such as β-lactams, fungicides, flavors, pheromones and vitamins. In this study, (R)-3-hydroxycarboxylic acid [(R)-3HAs)] synthons were produced by Streptomyces sp. JM3 (JN166713) under batch fermentation. Initial confirmation of PHA production was achieved by matrix assisted laser desorption ionization-time of flight mass spectroscopy and gas chromatography/mass spectroscopy (GC/MS). Subsequently, (R)-3HAs were produced by in vivo depolymerization and the monomers were separated using acid precipitation and anion exchange chromatography. The (R)-3HAs were identified by GC/MS as 3-trimethylsiloxy esters of decanoic, octanoic and butanoic acids. This was further supported by (13)C nuclear magnetic resonance spectrometry. The (R)-3HAs exhibited antimicrobial activity against Escherichia coli O157:H7, Listeria monocytogenes (ATCC 7644) and Salmonella typhimurium (ATCC 14028) with minimum inhibitory concentration ranging from 12.5 to 25 mg ml(-1). However, the minimum bactericidal concentration data suggest that the (R)-3HAs may be bactericidal for E. coli O157:H7 and bacteriostatic for S. typhimurium and L. monocytogenes. Furthermore, the major purified synthon was shown to minimize the invasion of fibroblasts by S. typhimurium (ATCC 14028) [p < 0.05], using the MTT assay [(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide)].
Department of Biology, Howard University, 415 College St. NW, Washington, DC 20059, USA. adriandallen@yahoo.com
Adrian Douglas
AD
Allen
Patrick
P
Daley
Folahan O
FO
Ayorinde
Ayelle
A
Gugssa
Winston A
WA
Anderson
Broderick E
BE
Eribo
D016475:3T3 Cells; D000818:Animals; D000890:Anti-Infective Agents / Q000032:analysis* / Q000494:pharmacology*; D015169:Colony Count, Microbial; D019453:Escherichia coli O157 / Q000187:drug effects; D005285:Fermentation; D005347:Fibroblasts / Q000382:microbiology; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry; D008089:Listeria monocytogenes / Q000187:drug effects; D051379:Mice; D008826:Microbial Sensitivity Tests; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis* / Q000494:pharmacology; D012486:Salmonella typhimurium / Q000187:drug effects; D013302:Streptomyces / Q000737:chemistry*
D000890:Anti-Infective Agents; D054813:Polyhydroxyalkanoates