*Article* **Utilization of Whey for Red Pigment Production by** *Monascus purpureus* **in Submerged Fermentation**

**Dilara Mehri <sup>1</sup> , N. Altinay Perendeci <sup>2</sup> and Yekta Goksungur 1,\***


**Abstract:** Various biotechnological approaches have been employed to convert food waste into value-added bioproducts through fermentation processes. Whey, a major waste generated by dairy industries, is considered an important environmental pollutant due to its massive production and high organic content. The purpose of this study is to investigate the effect of different fermentation parameters in simultaneous hydrolysis and fermentation (SHF) of whey for pigment production with *Monascus purpureus*. The submerged culture fermentation parameters optimized were type and pretreatment of whey, pH, inoculation ratio, substrate concentration and monosodium glutamate (MSG) concentration. Demineralized (DM), deproteinized (DP), and raw whey (W) powders were used as a substrate for pigment production by simultaneous hydrolysis and fermentation (SHF). The maximum red pigment production was obtained as 38.4 UA510 nm (absorbance units) at the optimized condition of SHF. Optimal conditions of SHF were 2% (*v*/*v*) inoculation ratio, 75 g/L of lactose as carbon source, 25 g/L of MSG as nitrogen source, and fermentation medium pH of 7.0. The specific growth rate of *M. purpureus* on whey and the maximum pigment production yield values were 0.023 h−<sup>1</sup> and 4.55 UAd−<sup>1</sup> , respectively. This study is the first in the literature to show that DM whey is a sustainable substrate in the fermentation process of the *M. purpureus* red pigment.

**Keywords:** microbial red pigment; *Monascus purpureus*; simultaneous hydrolysis and fermentation; sustainability; whey
