Effect of growth media modifications on cell biomass and polyunsaturated fatty acids (PUFAs) production from Shewanella frigidimarina

Abstract

Polyunsaturated fatty acids (PUFAs) are chemically present as esters, ethers, glycerides glycolipids, phospholipids, phosphonolipids, glycosphingolipids, sulpholipids and lipoproteins in storage oils and
membranes lipids. Marine microorganisms such as Shewanella frigidimarina are important sources of polyunsaturated fatty acids with promising biomedical applications, commercial value and the potential
ability to be used in the bioremediation of environments contaminated with petroleum hydrocarbons. The growth media dependency of S. frigidimarina in terms of its growth behavior in response to modifications made to the media as well as its potential to produce PUFAs was evaluated. S. frigidimarina was cultured in conventional shake-flasks and controlled bioreactors with a batch-type procedure using different media compositions. The media used included artificial sea water, modified
artificial sea water 1, modified artificial sea water 2, Luria Bertani, modified Luria Bertani, sodium pyruvate-yeast (PYS) and marine broth. The highest cell biomass was obtained from artificial sea water media with an optical density (OD₆₀₀) value of 0.15 and subsequent studies were carried out using this medium. To evaluate the potential for PUFA production, RNA transcripts of polyketide synthases (PKS) genes were isolated and reverse-transcriptase polymerase chain reaction (RT-PCR) with S. frigidimarina specific primers carried out. The results of the successful RNA extraction and subsequent RT-PCR revealed that modifications made to growth media compositions can affect the potential for PUFA production.

Keywords: Polyunsaturated fatty acids, Shewanella frigidimarina, media modification