TABLE 2.

Growth and AHL production of the S. liquefaciens wild-type MG1 and the estA mutant MG1-estA and activities of a P_estA transcriptional luxAB gene fusion on plasmid pSL1 in the wild-type background in minimal medium supplemented with different carbon sources^a

Carbon source	Growth rate (h−1)		Yield (OD600)b		C4-HSL production (%)c		Specific bioluminescenced (107) [MG1(pSL1)]
	MG1	MG1-estA	MG1	MG1-estA	MG1	MG1-estA
0.4% glucose	0.47	0.47	2.5	2.4	100	98	3.38 ± 0.04
0.4% fructose	0.34	0.34	2.3	2.3	97	84	NDe
0.4% saccharose	0.48	0.49	2.8	2.8	105	95	2.89 ± 0.06
0.4% citrate	0.34	0.33	1.6	1.6	88	86	ND
0.4% gluconate	0.32	0.32	1.6	1.6	86	92	ND
0.4% succinate	0.23	0.20	1.1	1.1	97	96	ND
1% glycerol	0.34	0.33	2.3	2.2	112	102	3.02 ± 0.05
1% Tween 20	0.26	0.19	1.8	1.3	77	18	2.13 ± 0.04
1% Tween 80	0.39	0.31	2.4	2.0	91	35	3.18 ± 0.06
1% olive oil	0.53	0.52	2.7	2.6	130	129	2.99 ± 0.04

^aAll values represent means from at least two independent experiments.

^bYield is defined as the maximum OD reached within 3 days of incubation.

^cSamples of spent culture supernatants were taken at an OD₆₀₀ of 1.0, and AHLs were quantified with the aid of the AHL monitor strain E. coli MT102(pSB403). The AHL concentration of the wild-type strain grown in minimal medium containing 0.4% glucose was arbitrarily set to 100%.

^dFollowing addition of 1 μl of n-decanal (Sigma) to 200 μl of sample, bioluminescence of MG1(pSL1) was quantified at various points during logarithmic growth in a Lumat LB 9506 luminometer (EG & Berthold, Bad Wildbad, Germany). Specific bioluminescence is defined as relative light units per OD₆₀₀ unit. Results are means and standard deviations for multiple samples taken during exponential growth, from at least two independent experiments.

^eND, not determined.