Effect of volatile organic compounds on planktonic growth and biofilm formation of Vibrio harveyi

The purpose of the work is to investigate the effect of various types of volatile organic compounds (VOCs) emitted by microorganisms (ketones, alcohols, terpenes, dimethyl disulfide — DMDS) on planktonic growth and biofilm formation by the gram-negative marine bacterium Vibrio harveyi BB120. This species of bacteria is a pathogen that causes infectious diseases in various marine organisms, vertebrates and invertebrates, which hinders the development of marine aquaculture. Materials and methods. Cells were grown in 96-well polystyrene plates with gentle shaking. Planktonic growth was determined by optical density. The level of biofilms formed was determined by staining them with crystal violet followed by extraction with ethyl alcohol. The intensity of the color of the solution was used to judge the level of biofilm formation. Results. It was shown that the action of all studied VOCs on the planktonic growth of V. harveyi BB120 led to a decrease in planktonic growth. (–)-limonene, β-ionone and (+)-α-pinene had the strongest effect on bacteria, and 2-phenylethanol had a slightly lesser effect. The level of biofilms (as a percentage of the control without VOCs) was in all cases higher under the influence of these VOCs than the level of planktonic growth of V. harveyi BB120, indicating a higher resistance to VOCs of cells in biofilms. The patterns of action of different VOCs on biofilm formation in the VOC ranges studied were different. With an increase in the amount of added 2-pentanone and DMDS, there was an increase in the formation of biofilms; adding (–)-limonene, 2-phenylethanol, isoamyl alcohol and (+)-α-pinene to the culture led to a decrease in the level of biofilms. Conclusion. For the first time, the growth-inhibiting effect of VOCs with different structures (2-pentanone, β-ionone, isoamyl alcohol, 2-phenylethanol, (–)-limonene, (+)-α-pinene, dimethyl disulfide) has been demonstrated. These data are of interest for the fight against infections caused by V. harveyi and other pathogenic representatives of the genus Vibrio.