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2 High-Efficient Anaerobic Fermentation Technology of Organic …
Ethanol and VFA
contents (mM)
Ethanol and VFA
contents (mM)
Time (h)
Time (h)
Fig. 2.23 Changes of content of volatile acids in the fermentation of straws
Component 2 has excitation wavelength at 210 nm and 270 nm and emission
wavelength at 350 nm and belongs to tryptophan-like fluorescence. In the anaerobic fermentation process, the value of fluorescence intensity of protein components
slightly rose. At 22 h, the value of fluorescence intensity of proteins was up to
9587.9 mM. This indicated that the reaction system was in acid environment and
most of methanogens died due to low pH, so that intracellular proteins were dissolved out. Therefore, fluorescence intensity of proteins firstly increased and then
decreased and finally reached 676.9 mM.
As for component 3, the excitation wavelength and emission wavelength are found
at 210 and 400 nm separately and it is the typical coenzyme NADH substance. The
value of fluorescence intensity also slightly increased at 22 h to 2565.4 mM and then