Characterization of the C50 carotenoids produced by strains of the cheese-ripening bacterium Arthrobacter arilaitensis

Pigments were extracted from cheese-ripening bacteria belonging to the species Arthrobacter arilaitensis, which plays a role in the colour of cheese. A chromatographic method was applied to characterise the pigment profile. Based on the UV-visible (UV-vis) spectra, the mass spectra, and the elution order, eight different carotenoids were identified from the strains. Four of the pigments, namely, all- E-decaprenoxanthin, all- E-sarcinaxanthin, 9- Z-decaprenoxanthin and 15- Z-decaprenoxanthin, which were present as free-form main carotenoids (i.e., non-glycosylated), have been characterised by their UV-vis and mass spectra, both in atmospheric-pressure chemical ionisation negative [APCI (-)] and positive modes. The other minor carotenoids, namely, sarcinaxanthin monoglucoside pentaacetate, decaprenoxanthin monoglucoside, decaprenoxanthin diglucoside, decaprenoxanthin-C16:0 (decaprenoxanthin-palmitate), present in very low amounts, were only detected in the APCI (-) ionisation mode. Our results provide the first chemical characterisation of the pigments produced by cheese-ripening A. arilaitensis strains, which has not previously been reported.