2.2 Pre-treatment Technologies of Anaerobic Fermentation
29
2.2.2.5 Influences of Pre-treatment on DOM
By using the blind parallel factor (PARAFAC) model, the researchers identified three
separate fluorescent components from the DOM (Fig. 2.13). Component 1 is centered
at 220/340 nm, the highest Ex/Em wavelength pair. In addition, it is associated with
typical protein-like substances, including tryptophan explored previously in effluents
of the fermentation. There are latest evidences providing support for the opinion
of component 1 being probably derived from phenolic compounds having Ex/Em
wavelength pairs resembling to those of component 1 and originating from the lignin
degradation. Component 1 occupying a dominant F max value in the DOM in the
hydrogenogenic stage on conditions of the three pre-treatments is the representative
protein-like substances. Nevertheless, no component 1 is found in the original FVWs
(i.e. the control). This result indicates that the protein-like substances in component
1 mainly stemmed from the newly formed DOM because of microbial and biological
activities which are related to the pre-treatments methods.
Component 2 comprises two excitation maxima at 225 and 275 nm, with one
emission peak at 330 nm. The two components exhibit Ex/Em characteristics like
those of protein-like fluorescent compounds and presumably a combination of fluorophores carrying fluorescent proteins tryptophan and tyrosine: free amino acid or
Component 1
Em. (nm)
Ex. (nm)
250
300
350
400
450
200
250
300
350
400
0
0.05
0.1
0.15
0.2
0.25
Component 2
Em. (nm)
Ex. (nm)
250
300
350
400
450
200
250
300
350
400
0
0.02
0.04
0.06
0.08
0.1
0.12
Component 4
Em. (nm)
Ex. (nm)
250
300
350
400
450
500
550
200
250
300
350
400
0
0.01
0.02
0.03
0.04
0.05
0.06
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
IN HS MS IN HS MS IN HS MS IN HS MS
Fmax
Different fermentation stages
Component 1
Component 2
Component 3
Blank
Acid
Alikia
Enzyme
Component 3
Fig. 2.13 The EEM spectra of the three component identified by PARAFAC analysis and maximum
fluorescence intensities (F max ) in different fermentation stages (Jia et al. 2014)
29
2.2.2.5 Influences of Pre-treatment on DOM
By using the blind parallel factor (PARAFAC) model, the researchers identified three
separate fluorescent components from the DOM (Fig. 2.13). Component 1 is centered
at 220/340 nm, the highest Ex/Em wavelength pair. In addition, it is associated with
typical protein-like substances, including tryptophan explored previously in effluents
of the fermentation. There are latest evidences providing support for the opinion
of component 1 being probably derived from phenolic compounds having Ex/Em
wavelength pairs resembling to those of component 1 and originating from the lignin
degradation. Component 1 occupying a dominant F max value in the DOM in the
hydrogenogenic stage on conditions of the three pre-treatments is the representative
protein-like substances. Nevertheless, no component 1 is found in the original FVWs
(i.e. the control). This result indicates that the protein-like substances in component
1 mainly stemmed from the newly formed DOM because of microbial and biological
activities which are related to the pre-treatments methods.
Component 2 comprises two excitation maxima at 225 and 275 nm, with one
emission peak at 330 nm. The two components exhibit Ex/Em characteristics like
those of protein-like fluorescent compounds and presumably a combination of fluorophores carrying fluorescent proteins tryptophan and tyrosine: free amino acid or
Component 1
Em. (nm)
Ex. (nm)
250
300
350
400
450
200
250
300
350
400
0
0.05
0.1
0.15
0.2
0.25
Component 2
Em. (nm)
Ex. (nm)
250
300
350
400
450
200
250
300
350
400
0
0.02
0.04
0.06
0.08
0.1
0.12
Component 4
Em. (nm)
Ex. (nm)
250
300
350
400
450
500
550
200
250
300
350
400
0
0.01
0.02
0.03
0.04
0.05
0.06
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
IN HS MS IN HS MS IN HS MS IN HS MS
Fmax
Different fermentation stages
Component 1
Component 2
Component 3
Blank
Acid
Alikia
Enzyme
Component 3
Fig. 2.13 The EEM spectra of the three component identified by PARAFAC analysis and maximum
fluorescence intensities (F max ) in different fermentation stages (Jia et al. 2014)