Veratraldehyde as a food additive produced by the marine isolate streptomyces diastaticus lc360811

Abstract

Twelve actinomycete isolates were derived from 6 sediment samples collected from the Red Sea coast, Egypt. The marine isolate, RS10, the most potent candidate, proved its capability to produce antimicrobial compound(s) that strongly inhibit both Gram-positive and Gram-negative bacteria. RS10 was identified by 16S rRNA gene sequencing as Streptomyces diastaticus LC360811. Culture supernatant of S. diastaticus LC360811 was extracted using n-butanol and tested against bacterial indicator strains using the disc diffusion method. The crude extract was partially purified using column chromatography and assessed for antimicrobial activity. Fraction no. 35 showed the highest antimicrobial activity against Acinatobacter sp. (34 mm), Pseudomonas aeruginosa ATCC 9027 (30 mm), Candida albicans (26 mm), Staphylococcus aureus ATCC 47077 (25 mm), Aeromonas hydrophila (23 mm), Streptococcus iniae (22 mm) and Borditella sp. (18 mm). This active fraction was then identified as veratraldehyde using spectroscopic techniques: GC-MS-MS and HPLC (diode array detector) and compared with the authentic reference. Veratraldehyde as a natural preservative proved to be a good candidate to preserve the flavor of juice, yoghurt and fermented milk and was able to control the growth of bacterial pathogens compared to the non-treated products till day fourteen.