Miniaturized techniques for analysis of industrial yeasts

Carotenoids are natural pigments that have antioxidation and antimutagenic abilities. They are produced with the help of new technological methods. For example, carotenoid yeast Rhodotorula glutinis produces -carotene with the yield of up to 6 – 10 mg/g of the dry substance. The method of the mass spectrometry with the nanoelectrospray in the positive mode was optimized for the determination of -carotene, lycopene and astaxanthin in this project. Ionizing voltage of 4 kV and the sample flow rate of 15 – 80 nl/min through the spray silica fused capillary with the internal diameter of 25 µm were found to be the optimum parameters of the analysis. A mixture of chloroform with the addition of ammonia was used as a spray solvent for both standard and cellular samples. During the process of ionization by nanoelectrospray, -carotene and lycopene form cation radical [M] • + with the molecular mass to charge ratio (m/z) of 536, while asthaxanthin forms the protonated molecule [M + H]+ with the m/z of 597. The partial lysis of individual Rhodotorula glutinis cells was demonstrated under microscope in the organic solvents tetrahydrofuran and dimethylsulfoxide. Chloroform, acetone, acetonitrille, methanol and isopropanol did not affect the cells after a 15 min treatment