TABLE 2.

Average SCFA levels over the experimental period for pHs 6.8, 7.5, and 8.5, as determined by high-performance liquid chromatography

Fatty acid	Amt of SCFA (mM)f
	Initial sample	pH 6.8 (T48)		pH 7.5 (T48)		pH 8.5 (T48)
		Lipids	Control	Lipids	Control	Lipids	Control
Lactic acid	8.3 ± 3.1	3.2 ± 3.0b,d,e	3.5 ± 0.6b,d,e	2.7 ± 2.5b,e	1.3 ± 0.7b	2.1 ± 2.1b	ND
Acetic acid	9.7 ± 4.2	17.7 ± 6.6a,d	13.7 ± 0.2e	19.4 ± 6.4b	13.9 ± 0.4	18.1 ± 4.9b	14.5 ± 0.2
Propionic acid	5.1 ± 4.2	13.2 ± 7.7b	12.9 ± 3.7b	13.4 ± 8.2b	12.5 ± 1.7	13.0 ± 5.8b	12.8 ± 0.8
Butyric acid	2.2 ± 2.1	10.8 ± 5.3b,c	1.6 ± 2.3	12.7 ± 8.2b,c	1.9 ± 0.1a,e	15.6 ± 11.4b,c	ND

^aSignificantly different from the initial sample (P < 0.05).

^bSignificantly different from the initial sample (P < 0.01).

^cSignificantly different from T48 control (P < 0.05).

^dSignificantly different from T48 sample at pH 7.5 (P < 0.05).

^eSignificantly different from T48 sample at pH 8.5 (P < 0.05).

^fAmounts of SCFA are means ± standard deviations (n = 12). The inoculum was human feces (1% [wt/vol]), and the incubations were carried out in batch culture for 48 h with phosphatidylcholine as the main substrate at a concentration of 0.5% (wt/vol). Control fermentors did not contain phosphatidylcholine. ND, not detected.