PHA Productivity and Yield of Ralstonia eutropha When Intermittently or Continuously Fed a Mixture of Short Chain Fatty Acids

Table 4

Comparison of all the key parameters under different ARF feeding strategies.

Key parameters		Feeding strategies
	24 h addition	3 h addition	Continuous addition
Cell population at 48 h (CFU^−1 mL)	4.28 × 10^10a	1.70 × 10^10b	1.01 × 10^10b
Maximum cell population (CFU^−1 mL)	5.03 × 10^10a	5.68 × 10^10a	5.47 × 10^10a
Ammonia utilization rate (g^−1 L^−1 h)	1.2^a	1.0^a	1.1^a
Phosphate utilization rate (g^−1 L^−1 h)	0.010^a	0.013^a	0.011^a
Acid utilization (g^−1 L^−1 h)
Acetic	0.029^a	0.052^b	0.047^b
Butyric	0.009^a	0.010^a	0.014^a
Lactic	0.074^a	0.080^a	0.078^a
Propionic	0.077^a	0.083^a	0.080^a
Combined	0.20^a	0.25^b	0.24^b
Fermentation efficiency (%)
Acetic	58.8^a	100^b	98.7^b
Butyric	94.7^a	100^b	100^b
Lactic	100^a	100^a	100^a
Propionic	95.7^a	100^b	95^a
Combined	82.7^a	100^b	97.8^b
PHA production
Cell dry weight (g^−1 L)	17.6^a	21.13^a	17.3^a
PHA concentration; (g^−1 L)	6.42^a	8.37^a	6.67^a
PHA productivity (g^−1 L^−1 h)	0.0537^a	0.0697^b	0.056^a
PHA content (%)	36.23^a	39.52^a	37.78^a

^a,b,cMeans within column not sharing common superscript differ significantly (P < 0.05).