Enhancement of Oxygen Mass Transfer and Gas Holdup Using Palm Oil in Stirred Tank Bioreactors with Xanthan Solutions as Simulated Viscous Fermentation Broths

Table 3

The empirical constants for 𝑘_𝐿𝑎 reported in the literature and in the current study.

Reference	Liquid system	Type of impeller	Constant β	Constant α	Constant γ	Valid for 𝑃𝑔/𝑉𝐿 (kW/m^3)	𝑅^2	Average error, %	Correlation
[10]	Perfluorocarbon (PFC) in YPD medium with inactive cells	Rushton turbine	0.302	0.699	−1.378	NA	NA	15.7	Nielsen et al. [20]; (10)
[20]	n-Hexadecane in broth medium	Rushton turbine	0.31	0.70	1.70	NA	NA	NA
[27]	Methyl ricinoleate in Yarrowia  lipolytica broth	Rushton turbine	0.6	0.8	−22	NA	NA	NA
[27]	Tween 80 in Yarrowia  lipolytica broth	Rushton turbine	0.4	0.7	−449	NA	NA	NA
Current study	Xanthan gum solution with 0 to 10% palm oil fraction	Rushton turbine	0.4773	0.1620	−6.6029	0.079 to 1.11	0.77	58.75	Nielsen et al. [20]; (10)
	Xanthan gum solution with 0% palm oil fraction	Rushton turbine	0.6674	0.2076	−6.6029	0.141 to 1.11	0.89	46.55
Current study	Xanthan gum solution with 5% palm oil fraction	Rushton turbine	0.5361	0.1225	−6.1622	0.094 to 0.89	0.78	58.74
	Xanthan gum solution with 10% palm oil fraction	Rushton turbine	0.4078	0.1702	−8.2896	0.079 to 0.89	0.68	46.47
	Xanthan gum solution with 15% palm oil fraction	Rushton turbine	0.4401	0.4253	−2.7865	0.058 to 0.83	0.74	40.93	Nielsen et al. [20]; (10)
	Xanthan gum solution with 20% palm oil fraction	Rushton turbine	0.4885	0.2777	−1.6270	0.039 to 0.72	0.98	15.59
	Xanthan gum solution with 50% palm oil fraction	Rushton turbine	0.4334	0.1605	−0.0697	0.031 to 0.64	0.86	34.40
Current study	Xanthan gum solution with 0% palm oil fraction	Rushton turbine	0.6674	0.2076	—	0.141 to 1.11	0.89	46.55	Cooper et al. [18]; (9)
	Xanthan gum solution with 5% palm oil fraction	Rushton turbine	0.5361	0.1225	—	0.094 to 0.89	0.78	58.73
	Xanthan gum solution with 10% palm oil fraction	Rushton turbine	0.4078	0.1702	—	0.079 to 0.89	0.68	46.47
	Xanthan gum solution with 15% palm oil fraction	Rushton turbine	0.5343	0.3054	—	0.058 to 0.83	0.96	18.80
	Xanthan gum solution with 20% palm oil fraction	Rushton turbine	0.4994	0.2740	—	0.039 to 0.72	0.98	14.00
	Xanthan gum solution with 50% palm oil fraction	Rushton turbine	0.4458	0.3391	—	0.031 to 0.64	0.91	27.67