Impact of temperature on Marinobacter hydrocarbonoclasticus SP17 morphology and biofilm structure during growth on alkanes
Résumé
Alkanes are widespread pollutants found in soil, freshwater and marine environments. Marinobacter hydrocarbonoclasticus (Mh) strain SP17 is a marine bacterium able to use many hydrophobic organic compounds, including alkanes, through the production of biofilms that allow their poor solubility to be overcome. This study pointed out that temperature is an environmental factor that strongly affects the biofilm formation and morphology of Mh on the model alkanes, hexadecane and paraffin. We showed that Mh biofilm formation and accumulation of intracytoplasmic inclusions are higher on solid alkanes (hexadecane at 10 °C and paraffin at 10 °C and 30 °C) than on liquid alkane (hexadecane at 30 °C) or soluble substrate (lactate at both temperatures). We also found that Mh produces more extracellular polymeric substances at 30 °C than at 10 °C on alkanes and none on lactate. We observed that bacterial length is significantly higher at 10 °C than at 30 °C on lactate and hexadecane. On paraffin, at 30 °C, the cell morphology is markedly altered by large rounded or irregularly shaped cytoplasmic inclusions. Altogether, the results showed that Mh is able to adapt and use alkanes as a carbon source, even at low temperature.
Mots clés
alkane
Physical state of the substrate/substratum
Marinobacter
Cell shape
Lipid inclusion
Poorly soluble substrate
Biofilm
Temperature
temperature
biofilm
poorly soluble substrate
lipid inclusion
cell shape
physical state of the substrate/substratum. Abbreviations: ANOVA
analyses of variance
CLSM
confocal laser scanning microscopy
HCB
hydrocarbonoclastic bacteria
HOC
hydrophobic organic compound
Mh
Marinobacter hydrocarbonoclasticus
SEM
scanning electron microscopy
SSW
synthetic seawater
TEM
transmission electron microscopy
Domaines
Sciences du Vivant [q-bio]
Origine : Publication financée par une institution