Abstract:The growth and fermentation of Saccharomyces cerevisiae are both complexed physiology process. Here, we used laser tweezers Raman spectroscopy (LTRS) as tool and reported physiological metabolism such as nucleic acid, proteins, lipid, ethanol and glucose in active dry wine yeast cells. Our results indicated significantly changes of intracellular components at 6 h during log growth phase and 9 h that point between aerobic respiration to anaerobic fermentation. RNA synthesis was rapidly trigged in cultivated media and reached the maximum at 6 h. However, mitochondria respiration and syntheses of protein and lipid were slower than metabolism of nucleic acid in initial 3 h and then reached the maximum at crucial 9 h. The ethanol was also yielded at this time accompanying increase of glucose metabolism and reached the maximum of 0.98%. However, later, the metabolism of macromolecular, expected mitochondria respirations, were deeply declining after 9 h. All results show that LTRS can be utilized to monitor the metabolism of yeast growth and fermentation in quantitative or semi-quantitative analyses. In addition, improved kinetic model of ethanol fermentation processes also can be benefited from these metabolism parameters.
