EVALUATION OF THE ANTIBACTERIAL ACTIVITY OF PIGMENT EXTRACTS AND 16S rRNA-BASED IDENTIFICATION OF PIGMENT-PRODUCING BACTERIA ISOLATED FROM SOIL

This study aimed to isolate pigment-producing bacteria from soil samples collected in the Artvin province for the first time, extract their pigments, and evaluate their antimicrobial activities.Fifteen bacterial isolates were obtained and identified through morphological and biochemical characterization, followed by 16S rRNA gene sequencing.The isolates were identified as Arthrobacter ruber (P1, P20), Rhodococcus sp.(P2, P6, P7), Micrococcus yunnanensis (P4), Metabacillus indicus (P5), Arthrobacter sp.(P9, P10), Peribacillus muralis (P12), Chitinophaga arvensicola (P16), Streptomyces lincolnensis (P17), Arthrobacter agilis (P18, P21), and Nocardia tenerifensis (P22).These isolates produced pigments in various hues such as red, pinkish-brown, yellow, yellowish-orange, light salmon-pink, and brownish tones.The antimicrobial activity of the pigment extracts was tested using dry disc diffusion method against Candida albicans, Staphylococcus aureus, Escherichia coli, and Proteus mirabilis.Only the methanol and acetone extracts of pigments from S. lincolnensis and N. tenerifensis exhibited inhibitory activity, specifically against S. aureus.Notably, the acetone extract of N. tenerifensis (P22) demonstrated the highest antimicrobial effect with a 17.6 mm inhibition zone.High-Performance Liquid Chromatography (HPLC) analysis confirmed the presence of bioactive compounds in these extracts.The findings highlight the significant biotechnological potential of these pigment-producing soil bacteria as sources of natural antimicrobial agents.