Commercial pineapple juice (Sweet Valley, Spitz Austria) was purchased from a
local market. Z. mobilis (DSMZ 473) and Rhodotorula mucilaginosa (DSMZ 70403)
were supplied by DSMZ (Braunschweig, Germany). Invertase (150 U mg−1) from
baker’s yeast (Saccharomyces cerevisiae) was purchased from Sigma. HPLC column
HPX 87C was from Bio-Rad (Hercules, CA).