Arginase Activity Characterization During Alcoholic Fermentation by Sequential Inoculation with Non-Saccharomyces and Saccharomyces Yeast

Arginine uptake and yeast arginase activity were studied throughout the alcoholic fermentation of a white grape must (Vitis vinifera L. cv Fiano), carried out by sequential inoculation (Torulaspora delbrueckii and S. cerevisiae, TD-SC) and compared with a S. cerevisiae single fermentation (SC). In both samples, yeast assimilable nitrogen (YAN) consumption was mainly during the early phase of alcoholic fermentation (before S. cerevisiae addition in the sequential fermentation). T. delbrueckii alone and S. cerevisiae similarly metabolized YAN, which was further consumed in TD-SC sample following the S. cerevisiae inoculation. The only relevant arginine uptake was found about 3 days after the first inoculum (simultaneously with the greatest YAN consumption) and it appeared to be higher in SC (0.24 g/L) than in TD-SC (0.12 g/L). The kinetic parameters, estimated by means of the Hill equation, and in particular V-max values (56.0 +/- 1.6 U/mg(BSAeq) at 48 h for SC and 73.3 +/- 2.7 U/mg(BSAeq) at 66 h for TD-SC) indicated the maximum arginase activity at the same point of time corresponding to the lowest YAN amount (48 h for S. cerevisiae and 66 h for T. delbrueckii).

Automated summary

The uptake of arginine and arginase activity in the alcoholic fermentation of white grape must were mainly observed in the early phase of fermentation, with maximum activity coinciding with the lowest YAN levels.