Table 2.

The components of main VOCs produced by B. subtilis CF-3 after different fermentation durations.

Possible VOC	Relative content (%)
	12hFL	24hFL	36hFL	48hFL	60hFL	72hFL	84hFL	96hFL
(S)-1-octanol	0.91 ± 0.28 b	3.27 ± 0.97a	0.47 ± 0.13 b	0.24 ± 0.09b	0.74 ± 0.21 b	0.33 ± 0.08 c	0.09 ± 0.03 c	0.09 ± 0.05 c
Benzoic acid	2.53 ± 0.69 c	9.16 ± 1.30 a	1.77 ± 0.12 b	0.39 ± 0.05 cd	1.24 ± 0.34 c	1.12 ± 0.16 de	0.69 ± 0.17 e	1.28 ± 0.27 e
2,4-di-tert-butylthiophenol	3.25 ± 0.47 b	12.32 ± 2.36 a	2.16 ± 0.59 b	1.17 ± 0.27 b	2.62 ± 0.36 b	0.60 ± 0.14 c	0.47 ± 0.11 c	0 c
Benzaldehyde	1.85 ± 0.68 c	7.24 ± 1.22 a	1.40 ± 0.21 b	0.44 ± 0.08 cd	1.15 ± 0.32 cd	1.75 ± 0.17 cde	1.22 ± 0.27 de	1.16 ± 0.36 e
3-methylbutanal	0.32 ± 0.07 bc	0.49 ± 0.11 ab	0.26 ± 0.08 a	0.17 ± 0.06 a	0.45 ± 0.13 a	0.36 ± 0.10 bcd	0.22 ± 0.04 cd	0.13 ± 0.03 d
Anisole	12.54 ± 2.85 ab	11.59 ± 2.38 bc	5.88 ± 1.07 ab	4.02 ± 0.95 ab	11.27 ± 3.14 a	18.35 ± 3.36 ab	18.05 ± 2.87 b	15.34 ± 1.63 c
Methoxy-phenyl-oxime	1.41 ± 0.28 d	9.23 ± 3.36 cd	39.04 ± 7.35 a	13.03 ± 4.82 b	34.95 ± 7.36 b	37.56 ± 10.28 c	37.77 ± 8.36 c	58.68 ± 6.21 c
Benzothiazole	1.25 ± 0.36 cd	4.54 ± 1.82 a	1.11 ± 0.17 b	0.55 ± 0.08 bc	1.49 ± 0.36 bc	2.17 ± 0.38 bc	0.31 ± 0.08 d	0.21 ± 0.09 d
Total peak area of all possible VOCs	5004596 ± 425236 d	4620461 ± 521412 d	11527435 ± 796523 b	19971460 ± 841253 a	7622145 ± 532115 c	3597881 ± 501027 e	3179336 ± 489365 e	1961563 ± 141255 f

The compounds possibly generated by CF-3 were identified by comparing their mass spectra to those in the NIST Mass Spectral Library (probability-based match >85%). Values are expressed as means of the relative content of each compound (n = 3). To express the variation of the VOCs more accurately, peak area (relative content (%) × total peak area of all possible VOCs) was used in ANOVA. The different letters represented significant differences (P < 0.05) between the B. subtilis CF-3 fermentation liquids for different fermentation durations.