*3.4. Effect of Initial Lactose Concentration on Pigment Production*

*3.4. Effect of Initial Lactose Concentration on Pigment Production*  The effect of lactose concentration on pigment production by *M. purpureus* CMU 001 was investigated with DM whey containing different initial lactose concentrations as 25, 50, 75, and 100 g/L by SHF at 30 °C for 8 days. The initial pH of the fermentation medium was 7.0. The highest pigment density was determined as 27.7 UA510 nm in the fermentation medium containing 75 g/L of lactose (Figure 4). Red pigment concentrations of 10.2, 25.4, and 25.3 UA510 nm were found for the fermentation media containing initial lactose concentrations of 25, 50, and 100 g/L, respectively. Chen and Johns [52] reported that high glucose concentration of 50 g/L led to low biomass, pigment synthesis and ethanol production, while high maltose concentration of 50 g /L increased red pigment production by three fold compared to the same concentration of glucose. Liu et al., [53] studied pigment production by *M. purpureus* M183 and found the optimum glucose concentra-The effect of lactose concentration on pigment production by *M. purpureus* CMU 001 was investigated with DM whey containing different initial lactose concentrations as 25, 50, 75, and 100 g/L by SHF at 30 ◦C for 8 days. The initial pH of the fermentation medium was 7.0. The highest pigment density was determined as 27.7 UA510 nm in the fermentation medium containing 75 g/L of lactose (Figure 4). Red pigment concentrations of 10.2, 25.4, and 25.3 UA510 nm were found for the fermentation media containing initial lactose concentrations of 25, 50, and 100 g/L, respectively. Chen and Johns [52] reported that high glucose concentration of 50 g/L led to low biomass, pigment synthesis and ethanol production, while high maltose concentration of 50 g /L increased red pigment production by three fold compared to the same concentration of glucose. Liu et al., [53] studied pigment production by *M. purpureus* M183 and found the optimum glucose concentration as 80 g/L in terms of maximum efficiency, pigment yield and cost efficiency for industrial applications. Parallel to our findings, they stated that the initial substrate concentration has a negligible effect on biomass (dry cell weight). The high glucose concentration in the fermentation medium can be an advantage for mycelium growth, but as fermentation progresses, the fermentation medium becomes more acidic and this can lead to low pigment yields [54].
