TABLE 1.

Yields and production rates obtained in each batch experiment.

	Batch	Durationa (h)	Average currenta (mA)	Yield (mol mol–1 lactate consumed)			Highest production rate (mM d–1)
				Propionate	Acetate	Butyrateb	Propionate	Acetate	Butyrateb
LB1	I	158.4	2.19	0.39	0.32	−	4.49	2.67	−
	II	120.0	5.39	0.23	0.31	−	2.2	1.71	−
	III	148.8	6.5	0.28	0.36	−	2.76	2.25	−
	IV	139.2	7.68	0.18	0.23	−	1.87	1.00	−
LB2	I	158.4	2.42	0.17	0.18	−	1.98	1.39	−
	II	120.0	3.62	0.21	0.18	−	4.96	3.91	−
	III	148.8	4.51	0.16	0.35	−	2.12	2.81	−
	IV	139.2	5.43	0.19	0.10	−	3.13	1.27	−
L1	I	146.4	1.28	0.28	0.28	0.00	4.74	2.55	0
	II	244.8	2.03	0.30	0.39	0.02	7.2	5.13	0.14
L2	I	146.4	2.08	0.37	0.34	0.00	5.86	2.83	0
	II	244.8	5.44	0.28	0.30	0.02	6.16	4.44	0.12
L3	I	381.6	2.18	0.48	0.30	0.08	12.88	7.22	1.26
CLB1_pH5	I	285.0	None	0.03	0.10	−	0.04	0.20	−
CLB2_pH5	I	285.0	None	0.02	0.34	−	0.07	0.48	−
CLB1_pH7	I	285.0	None	0.44	0.42	−	2.53	1.53	−
CLB2_pH7	I	285.0	None	0.39	0.42	−	2.40	1.65	−
CL1_pH5	I	285.0	None	0.25	0.28	0.19	1.67	2.07	0.80
CL2_pH5	I	285.0	None	0.16	0.37	0.22	0.82	1.15	0.96
CL1_pH7	I	285.0	None	0.36	0.37	0.00	2.78	1.47	0.09
CL2_pH7	I	285.0	None	0.45	0.36	0.01	3.94	2.08	0.08

For EF experiments, the data reported include carboxylates detected in the catholyte and anolyte. C_LB and C_L refer to the non-electrochemical control experiments with lactate and butyrate, or only lactate, as substrate, respectively.

^aThe start-up period at −1.2 V applied potential was excluded.

^bButyrate yield and production rate are not included for LB1, LB2, C_LB2, or C_LB2 because butyrate was added at the beginning of the experiment.