The effect of nutrient composition on the accumulation of secondary metabolites from Janthinobacterium

The strains of Janthinobacterium IB-ST-GO, UIB-ST-GOLI and IB-ST-GOR, producers of prodigiosin and violacein, isolated from the underground karst lake of the Shulgan-Tash cave were used in the work. Various patterns of accumulation of pigments and indole-3-acetic acid (IAA) on media LB 0.5 and King B were found for the strains. A maximum of violacein from UIB-ST-GO on media King B reached and abrupt value (67.2 µg/ml), whereas on media LB 0.5 was determined a consistently high level (55 µg/ml) for 3-5 days. For IB-ST-GOR, maximum prodigiosin were detected at 6.9 and 7.4 µg/ml, respectively, on media LB 0.5 and King B on 3 days. The maximum yields of IAA in all strains were recorded on media King B on 4 days, and they exceeded the IAA values on media LB 0.5 for IB-ST-GO, IB-ST-GOR and IB-ST-GOLI by 1.8, 2.3 and 1.4 times, respectively. The growth-stimulating activity of the strains was tested on 7 daily wheat seedlings. Treatment with UIB-ST-GOLI and IB-ST-GO increased the length of wheat roots by 1.3 and 1.5 times compared to the control, respectively. The positive effect of treatment with IB-ST-GOR was manifested in a significant increase in the number of roots in plant seedlings by 29.7% compared with the control.