Marine Vibrio species produce the volatile organic compound acetone

Abstract

While screening aerobic, heterotrophic marine bacteria for production of volatile organic compounds, we found that a group of isolates produced substantial amounts of acetone. Acetone production was confirmed by gas chromatography, gas chromatography-mass spectrometry, and high-performance liquid chromatography. The major acetone producers were identified as nonclinical Vibrio species. Acetone production was maximal in the stationary phase of growth and was stimulated by addition of L-leucine but not the other common amino acids, suggesting that leucine degradation leads to acetone formation. Acetone production by marine vibrios may contribute to the dissolved organic carbon associated with phytoplankton, and some of the acetone produced may be volatilized to the atmosphere. It is now known that the biosphere emits large quantities of volatile organic compounds (VOCs) into the atmosphere. Some VOCs, like methane, isoprene, and monoterpenes, are emitted from terrestrial sources at levels of hundred of millions of metric tons per year on a global basis and have important effects on atmospheric chemistry and global climate (12, 20). Oceans are significant sources of light hydrocarbons, including ethane, ethylene, propane, and propylene (reviewed in reference 26). Presumably, many of these marine hydrocarbons are produced by phytoplankton, which are known to produce a complex array of VOCs (29). Recently, it was reported that the VOC isoprene is produced in seawater (6, 19, 22). We set out to determine if marine microorganisms could be responsible for this production. During these investigations we detected substantial production of acetone by marine heterotrophic bacteria; our observations concerning this acetone production are reported in this paper. MATERIALS AND METHODS Screening marine bacteria for acetone production. Marine heterotrophic bacteria were isolated from seawater by inoculating seawater onto enriched seawater agar containing 80% (vol/vol) seawater, 0.1% (wt/vol) glucose, 0.1% (wt/vol) Bacto Tryptone, and 0.01% (wt/vol) yeast extract. The plates were incubated at 20 to 22ЊC and, after visible colonies were obtained, were sealed with Parafilm for 4 to 16 h to allow VOCs to accumulate in the headspace above the agar layer. Gas samples were removed with a gas-tight syringe by passing a side port needle though the Parafilm. Usually, 0.25-to 1.0-cm 3 gas samples were removed (approximately 1 to 4% of the available headspace) for analysis by gas chromatography (GC). We used two different instruments and detectors for GC. In our initial experiments we used a Photovac model 10S portable instrument (GC method A); this instrument was equipped with a 6-foot (ca. 183-cm) type CPSil-5 capillary column and a photoionization detector. The carrier gas was hydrocarbon-free air (8 cm 3 min Ϫ1), and the column was typically operated at 23ЊC; under these conditions acetone eluted at 73 Ϯ 2 s. In later experiments, we used a Hewlett-Packard model 5790A instrument equipped with a flame ionization detector and 30-m type DB-...

The role of the ocean in the global atmospheric budget of acetone

“…Production can take place by photo‐degradation of dissolved organic matter [ Zhou and Mopper , 1997] and directly by phytoplankton and bacteria [ Nemecek‐Marshall et al , 1995]. Loss can take place by photo‐degradation or biotic consumption [ Mopper and Stahovec , 1986; Nemecek‐Marshall et al , 1995]. Two recent field campaigns support a biologically mediated acetone source in seawater.…”

“…A major uncertainty in the budget of atmospheric acetone is the role of the ocean. Photochemical and biological processes in the ocean both produce and consume acetone [ Nemecek‐Marshall et al , 1995; Sinha et al , 2007; Zhou and Mopper , 1997]. Atmospheric acetone concentrations over the remote oceans are in the range of 200–500 pptv [ Singh et al , 2000], only a factor of 3–4 lower than over continental source regions.…”

Oceanic uptake and the global atmospheric acetone budget

“…Previous budgets have ranged widely in the ocean's role, varying from a 21 Tg yr −1 source [ Jacob et al , 2002] to a 14 Tg yr −1 sink [ Singh et al , 2004]. Acetone can be produced in surface waters by the solar irradiation of dissolved organic matter [ Kieber et al , 1990; Zhou and Mopper , 1997] and by microbial metabolism [ Nemecek‐Marshall et al , 1995]. There have been limited observations of acetone in oceanic waters [ Zhou and Mopper , 1997; Williams et al , 2004] and the only direct flux measurements of acetone have been over land [ Shaw et al , 1998].…”

Effect of a Povidone-Iodine Treatment on Litopenaeus vannamei Larvae in a Commercial Hatchery Setting

“…can cause poor growthhrvival performance of shrimp larvae in commercial hatcheries. It has been suggested that the mechanism influencing Q Copyright by the World Aquaculture Society 2005 larval mortality is related to the production of extracellular proteases and/or toxins from these bacterial strains (Long et al 1981;Nemeck-Marshal et al 1995).…”