Fig. 2From: Using Raman spectroscopy and chemometrics to identify the growth phase of Lactobacillus casei Zhang during batch culture at the single-cell levelPrincipal component analysis (PCA) of Raman spectra for normal L. casei Zhang. PCA scatterplot using the PC1, PC2, and PC3 values. Raman spectra acquired at lag phase (1–4 h), log phase (8–14 h), and stationary phase (18–30 h) are represented by different symbolsBack to article page