none 10.31254/phyto.2025.14604 BioMed Research Publishers BioMed Research Publishers 16195 189925508 316921 20260210015631888 10.31254 2026-02-10T01:56:40Z 2026-02-10T01:56:37Z 0 The Journal of Phytopharmacology J Phytopharmacol 2320480X 10.31254/phyto https://phytopharmajournal.com/ 1 30 2026 14 6 Abhishek Kumar https://orcid.org/0000-0002-7231-8507 Shardendu Background: Violacein is a purple pigment synthesized by select Gram-negative bacteria, including Janthinobacterium lividum, with potential antimicrobial and competitive advantages in environmental niches. Despite extensive research, the optimal conditions for violacein production remain incompletely understood. Objective: This study investigates the influence of different carbon sources (glucose and glycerol) on violacein production by J. lividum over time and examines the relationship between bacterial viability and pigment synthesis. Materials and Methods: J. lividum was cultured in LB medium supplemented with either 1% glucose (LB-U) or 1% glycerol (LB-Y). Violacein production was monitored using optical density measurements at 585 nm (OD585) and confirmed by high-performance liquid chromatography (HPLC). Colony-forming unit (CFU) counts were determined at multiple time points over 120 hours. Results: Glycerol-supplemented media demonstrated superior violacein production compared to glucose-supplemented media. In LB-Y conditions, violacein production reached 1.0 OD585 by 120 hours, while LB-U conditions achieved only 0.1 OD585. HPLC analysis confirmed violacein identity with a characteristic peak at 16.40 minutes retention time. Bacterial viability remained higher in violacein-positive cultures during the death phase. Conclusion: These findings demonstrate that carbon source selection critically influences violacein biosynthesis in J. lividum, with glycerol promoting enhanced production while glucose suppresses pigment synthesis. The results suggest violacein may contribute to bacterial survival under stress conditions. 1 30 2026 443 447 1 10.31254/biomed-crossmark-policy www.biomedresearch.org false 10.31254/phyto.2025.14604 https://phytopharmajournal.com/articles/abstracts/861/year=2025&vol=14&issue=6