Model-based driving mechanism analysis for butyric acid production in Clostridium tyrobutyricum

Table 3 Comparison of butyrate production using different strains and fermentation modes

Strain	Fermentation mode and pH strategy	Glucose consumed (g/L)	Acetate (g/L)	Lactate (g/L)	Butyrate
Strain	Fermentation mode and pH strategy	Glucose consumed (g/L)	Acetate (g/L)	Lactate (g/L)	Titer (g/L)	Yield (g/g)^b	BA/TA purity^a (%)
WT	Serum bottle with CaCO₃ as a pH buffer	58.86 ± 0.77	6.75 ± 0.38	0	22.12 ± 0.00	0.38 ± 0.00	76.82 ± 0.76
WT + AC		54.79 ± 6.81	6.03 ± 0.16	0	22.33 + 0.54	0.41 ± 0.04	70.14 ± 0.24
PfdxE-hydA		31.18 ± 0.19	0.00 ± 0.00	0.72 ± 0.42	15.43 ± 0.55	0.49 ± 0.02	95.63 ± 2.34
PfdxE-hydA + AC		58.60 ± 0.61	1.10 ± 0.13	0	24.78 ± 0.39	0.42 ± 0.01	83.72 ± 0.22
ΔhydA		41.18 ± 4.80	2.46 ± 0.25	0	19.53 ± 1.41	0.48 ± 0.02	88.91 ± 1.48
Δhyd1		48.02 ± 3.45	5.00 ± 0.01	0	21.17 ± 0.26	0.44 ± 0.03	81.24 ± 0.15
Δhyd2		52.56 ± 2.33	5.74 ± 0.01	0	18.81 ± 0.14	0.36 ± 0.02	76.81 ± 0.19
WT	Bioreactor pH 5.5	52.43 ± 3.40	6.44 ± 1.01	0	17.62 ± 1.68	0.34 ± 0.01	73.30 ± 1.22
WT	Bioreactor pH .6.0	63.30 ± 3.16	6.89 ± 0.53	0	17.54 ± 1.65	0.29 ± 0.01	71.80 ± 0.33
WT	Bioreactor pH 6.5	50.19 ± 0.38	0.50 ± 0.11	6.53 ± 0.63	16.97 ± 0.52	0.34 ± 0.01	70.70 ± 2.16
ΔhydA	Bioreactor pH 5.5	44.68 ± 9.46	2.72 ± 2.24	0	18.25 ± 1.433	0.41 ± 0.05	87.75 ± 8.53
ΔhydA	Bioreactor pH 6.0	50.02 ± 0.86	2.89 ± 0.98	0	19.29 ± 1.50	0.39 ± 0.02	86.90 ± 4.71
ΔhydA ^c	Bioreactor pH 6.5	45.60 ± 3.16	2.08 ± 0.02	12.32 ± 0.19	14.09 ± 1.76	0.31 ± 0.06	44.05 ± 2.72^c

^aBA/TA purity was calculated by the butyrate concentration divided by the total acid concentration, multiplied by 100%
^bYield based on glucose
^cFor the fermentation of the ΔhydA mutant at pH 6.5, there was 3.43 ± 0.05 g/L formate accumulation at the end of the fermentation. Therefore, the total acid concentration of the fermentation of the ΔhydA mutant at pH 6.5 included this concentration of formate

ISSN: 2731-3654