Table 2.
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.