*2.1. Microorganisms and Culture Media*

The microorganism used in this study was the *Monascus purpureus* CMU 001 kindly provided by the Department of Biology, Chiang Mai University of Thailand. Our previous work [37] has showed that this strain did not produce the mycotoxin citrinin, which is a secondary metabolite of *Monascus* species. The strain was kept on potato dextrose agar (PDA; pH:5.6 ± 0.2, Merck, Darmstadt, Germany) at 4 ◦C and sub-cultured every 4 weeks to fresh PDA slants incubated at 30 ◦C for 7 days.

Raw whey powder, demineralized whey powder and deproteinized whey powder were supplied by Enka Süt ve Gıda Mamulleri Sanayi ve Ticaret A.S. located in Konya city, Turkey. All the whey samples were sweet whey-based samples as declared by the supplier. β-galactosidase (Saphera 2600L) enzyme was kindly donated by Novozymes A/S (Bagsvaerd, Denmark) for the hydrolysis of lactose in whey. Saphera 2600L is a bacterial β-galactosidase enzyme from *Bacillus licheniformis* with a specific activity of 2600 LAU-B/g (enzyme activity was stated as β-galactosidase that hydrolyzes terminal non-reducing β-D-galactosides releasing beta-D-galactose residues). Whey powder was diluted with distilled water to contain 50 g/L lactose concentration (unless otherwise stated) for fermentation experiments.
