Identification of biochemical pathways contributing to oil tolerant ability of Dunaliella tertiolecta

Exposure to oil has been shown to be lethal to most phytoplankton species, however, some are able to survive and grow at normal or reduced growth rates. This ability to tolerate oil exposure appears to be independent of the class and phylum of the phytoplankton and their ability to consume components of oil heterotrophically. We, therefore, conducted an experiment on oil-resistant chlorophyte; Dunaliella tertiolecta in control and water accommodated fraction of oil (WAF) with and without metabolic inhibitors targeting biochemical pathways (photosynthetic electron transport, cyclic electron transport of PSI, Kreb’s cycle, mitochondrial electron transport, pentose-phosphate pathway and photo-respiration). We found inhibiting pathways such as photosynthetic electron transport and pentose-phosphate pathway were lethal, however, inhibition of pathways such as mitochondrial electron transport chain and cyclic electron transport around PSI caused growth arrest in cells. Pathways such as photorespiration and Kreb’s cycle played a critical role in oil tolerating ability of Dunaliella tertiolecta. Analysis of photo-physiology revealed alteration in the photosynthetic apparatus under inhibition of photo-respiration and not Kreb’s cycle. Further studies on how these photo-respiration and Kreb’s cycle help the survival of Dunaliella tertiolecta is under way.