Fig. 2

Shake flask cultivation of SR21 in 10 g L^− 1 hydrophobic substrates (HS) and glucose (72 h). (a) Growth-associated parameters (substrate consumption (%), dry cell weight (DCW; g L^− 1)), lipid and DHA (% and g L^− 1) are shown. The indicated values represent the mean and s.d of three biological replicates; (b) Saturation profile i.e., saturated fatty acid (SFA), monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) content of HS; (c) Fatty acid profile of HS analyzed by gas chromatography-mass spectrometry (GC-MS); (d) Principal Component Analysis (PCA) of the HS fatty acids and intracellular DHA (DHAintra). The PCA biplot is visualizing the HS as scores of different colors and their fatty acid profile as loading factors of blue color. Intracellular DHA (DHAintra) is shown as a loading factor of red color. A total of 72.57% variance of the dataset is explained by principal component (PC) 1 and 2, where PC1 accounts for 54.1% and PC2 for 18.46% of the variance; (e) Correlation map using Spearman’s correlation analysis between DHAintra and each of the fatty acids present in all HS used in this study. Spearman’s rho (r) is illustrated as color variation, where red color indicates a positive r-value and blue a negative r-value. The asterisks denote statistical significance * (p < = 0.05), ** (p < = 0.01) of the correlation between the variables examined