Fig. 4

Effect of temperature, initial pH, rotation speed and volume of medium on d-limonene or l-limonene accumulation of Po1g KdHR or Po1g KlHR. a Effect of temperature on d-limonene or l-limonene accumulation of Po1g KdHR or Po1g KlHR. The cultivation was performed at 200 rpm with an initial OD₆₀₀ of 0.1 and 8% of n-dodecane in 30 mL of liquid YPD medium in a 250-mL shake flask for 5 days at different temperatures (15, 20, 25 and 30 °C). b Effect of rotation speed on d-limonene or l-limonene accumulation of Po1g KdHR or Po1g KlHR. The cells were cultivated at 30 °C with an initial OD₆₀₀ of 0.1 and 8% of n-dodecane in 30 mL of liquid YPD medium in a 250-mL shake flask for 5 days at different rotation speeds (100 rpm, 150 rpm, 200 rpm and 250 rpm). c Effect of initial pH on d-limonene or l-limonene accumulation of Po1g KdHR or Po1g KlHR. The cultivation was performed at the optimum fermentation temperature of 20 °C and the optimum rotation speed of 250 rpm, with an initial OD₆₀₀ of 0.1 and 8% of n-dodecane in 30 mL of liquid YPD medium in a 250-mL shake flask for 5 days at six different initial pH values ranging from 3 to 10. d Effect of volume of medium on d-limonene or l-limonene accumulation of Po1g KdHR or Po1g KlHR. The cultivation was performed at the optimum fermentation temperature of 20 °C, the optimum rotation speed of 250 rpm, with an initial OD₆₀₀ of 0.1 and 8% of n-dodecane in a 250-mL shake flask for 5 days at different volumes of liquid YPD medium (25 mL, 50 mL, 75 mL and 100 mL). : d-limonene accumulation of Po1g KdHR; : l-limonene accumulation of Po1g KlHR; : biomass accumulation of Po1g KdHR; : biomass accumulation of Po1g KlHR. All values presented are the mean of three biological replicates ± standard deviation