Screening of the best carbon and nitrogen sources for pseudomonas aeruginosa as a potential polyhydroxyalkanoates (PHAs) and rhamnolipids producer

180Soil samples were collected from oil-polluted area and three isolates were screened as potential producer of PHAs and rhamnolipids. The identity of the isolates was confirmed as P. aeruginosa using biochemical tests and 16S rRNA sequencing. The main objective of this study was to screen for the best combination of carbon and nitrogen sources that support the optimal growth of this strain using predetermined medium at pH 6.8. The medium composition was 3.0 g KH₂PO₄, 7.0 g K₂HPO₄, and 0.2 g MgSO₄.7H₂O with addition of different combinations of carbon and nitrogen sources for different runs of fermentation using shake flask scale, at temperature 37°C, as suggested by the full factorial design. From the ANOVA, the significant factors that contributed to the optimum growth of P. aeruginosa were palm oil as carbon source and ammonium nitrate as nitrogen source. The highest value of cell dry weight (CDW) was achieved at 5.22 g/L comprising of 5% (w/v) of each carbon source and 3% (w/v) of each nitrogen source. Further study on optimization of both PHAs and rhamnolipids using response surface methodology (RSM) is suggested.