Continuous n-valerate formation from propionate and methanol in an anaerobic chain elongation open-culture bioreactor

Table 5 Setup for the different phases of the continuous formation of valerate and n- and iso-butyrate from propionate, acetate and methanol to study the effect of methanol increase on n- and iso-butyrate and n-valerate formation

Phase conditions	Phase I	Phase II	Phase III	Phase IV	Phase V	Phase VI
Hydraulic retention time (h)	46.3	42.5	45.4	∞	90.5	87.8
Phase duration (days)	0–17	17–20	20–38	38–45	45–71	71–104
pH influent	7.0	5.8	5.8	5.8	5.8	5.8
pH reactor	6.9 ± 0.1	6.1 ± 0.2	5.8 ± 0.1	5.8 ± 0.0	5.7 ± 0.1	5.8 ± 0.1
CO₂ supply (mL/min)	0	0	0.18	0.36	0.36	0.36
Methanol in influent (mM)	250	250	250	–	250	400

The changed parameters are indicated in italic
The pH in the reactor was controlled during phase II to phase VI. The methanol concentration of the influent was increased from 250 mM to 400 mM in phase VI. The reactor was in batch mode during phase IV

ISSN: 2731-3654