Table 2.

Growth characteristics of D. alaskensis G20 cocultures on 30 mM lactate in chemostat with different methanogens and dilution rates^a

Parameter	Coculture pairing/dilution rate
	G20 + M. maripaludis		G20 + M. hungatei
	0.047 h−1	0.027 h−1	0.027 h−1
Batch mode growth
Maximum growth rate	0.051 h−1	0.051 h−1	0.031 h−1
Mean maximum OD600 ± SD	0.30 ± 0.01	0.30 ± 0.01	0.25 ± 0.01
Chemostat
Start after inoculation (h)	60–65	60–65	105–120
Mean OD600 at steady state ± SD	0.29 ± 0.01	0.25 ± 0.01	0.21 ± 0.01
Cell ratio (Desulfovibrio/methanogen)	1.4	1.0	1.2
Organic acid concn (mM)
Lactate	< 0.05	< 0.05	< 0.05
Acetate	26–28	26–28 mM	26–28
Formate	NDb	ND	ND
Gas content
Methane (%)	50–60	30–40	30–40
Hydrogen (ppm)	350–550	280–400	70–110
Carbon monoxide (ppm)	10–15	7–9	4–6

^aAverage values of three replicate chemostats for each pairing/growth rate are shown.

^bND, no data (below the detection limit of IC).