TABLE 4.

Fermentation products and enzyme assay result of T. saccharolyticum and C. thermocellum

Strain	Description	Amt of fermentation product (mmol)a					Ethanol/acetate ratio (mmol/mmol)b	Ethanol yield (%)c	FNOR sp act (U/mg)d
		Lactate	Formate	Ethanol	Acetate	H2			NADH	NADPH
LL1025	Wild-type T. saccharolyticum JW/SL-YS485	0.16 ± 0.02	0.02 ± 0.00	1.26 ± 0.02	0.76 ± 0.01	1.72 ± 0.05	1.66 ± 0.04	23	0.56 ± 0.13	0.29 ± 0.12
LL1049	LL1025 Δpta Δack Δldh adhEG544D							42 (19)	0.18 ± 0.03	0.74 ± 0.15
LL1145	LL1025 Δpta Δack Δldh ΔpyrF ΔnfnAB::Kanr							42 (19)	0.48 ± 0.04	0.04 ± 0.01
LL1352	LL1025 ΔxynA::0705 Eryr								0.45 ± 0.18	0.27 ± 0.10
LL1353	LL1025 ΔxynA::1705 Eryr								2.51 ± 0.44	0.15 ± 0.07
LL1305	LL1025 Δtdk	0.17 ± 0.02	0.02 ± 0.01	1.28 ± 0.01	0.77 ± 0.01	1.7 ± 0.1	1.67 ± 0.02	23	0.57 ± 0.08	0.32 ± 0.10
LL1306	LL1305 Δ1705	0.23 ± 0.01	0.02 ± 0.02	1.30 ± 0.02	0.88 ± 0.01	1.9 ± 0.2	1.57 ± 0.03	24	0.18 ± 0.07	0.35 ± 0.11
LL1317	LL1305 ΔnfnAB::Kanr	0.22 ± 0.03	0.02 ± 0.00	1.31 ± 0.01	0.91 ± 0.01	2.4 ± 0.2	1.44 ± 0.02	24	0.48 ± 0.10	0.03 ± 0.01
LL1316	LL1305 Δ1705 ΔnfnAB::Kanr	0.26 ± 0.02	0.02 ± 0.01	1.06 ± 0.02	0.99 ± 0.2	2.7 ± 0.1	1.07 ± 0.03	19	0.15 ± 0.04	0.04 ± 0.01
LL1004	Wild-type C. thermocellum strain DSM 1313							16 (22)	0.21 ± 0.04	NDe
LL1087	LL1004 Δhpt Δrnf	0.72 ± 0.04	1.23 ± 0.03	1.42 ± 0.02	2.11 ± 0.03		0.67 ± 0.02	14	0.27 ± 0.04	ND
LL1338	LL1087(pDGO126-1705)	0.47 ± 0.02	1.14 ± 0.03	1.83 ± 0.03	1.82 ± 0.02		1.00 ± 0.02	18	0.34 ± 0.06	ND

^aFor quantification of all the fermentation products, the working volume was 50 ml on 0.72 mmol cellobiose for T. saccharolyticum and 14.4 mmol for C. thermocellum, and the headspace volume are 50 ml for a 100-ml serum bottle. Values are means ± standard deviations; n = 3.

^bValues are means ± standard deviations; n = 3.

^cEthanol yield is in grams per gram of glucose produced from cellobiose. Values are means (reference numbers are given in parentheses); n = 3.

^dSpecific activity determined from cell extracts. FNOR activity was determined using the NADH:BV assay. Values are means ± standard deviations; n = 3.

^eND, not detected.