The chemometric approach applied to FTIR spectral data for the analysis of lipid content in microalgae cultivated in different nitrogen sources

Microalgae-based biofuel production has emerged as a potential sector to extend its sustainability. Corresponding to many factors imbibed, nitrogen is considered as an essential element for microalgae cultivation. Among the four studied nitrogen sources, sodium nitrate (Na) and urea (U) showed high lipid content of 35.86 +/- 2.3 and 37.35 +/- 0.32 %, respectively. In terms of lipid yield, the four investigated nitrogen sources are represented in preferrential order, i.e., urea > sodium nitrate > ammonium nitrate > potassium nitrate. The Fourier transform infrared spectroscopy (FTIR) fingerprint of oil recovered from Chloromonas species ADIITEC-III, cultivated in different nitrogen sources, were analyzed using chemometric techniques. The chemometric techniques, i.e., cluster analysis, multidimensional scaling (MDS), and a multivariate calibration of principal component analysis (PCA), were assessed to analyze the existing spectral signatures specific to the lipid-acyl chain (3000-2800 cm(-1)) and biomolecular fingerprint region (1800-1000 cm(-1)) in the FTIR spectrum of the sample. The study of FTIR-coupled chemometric techniques complements the response of the nitrogen sources in lipid yield and confirmed the reliability of the method.