40
2 High-Efficient Anaerobic Fermentation Technology of Organic …
E x /E m wavelength pair of 225/340 and 280/340 nm. It was a combination of tyrosine protein-like and tryptophan materials according to the result. The main peak at
280/340 nm and identified in Component 1 refers to the attributes of soluble microbial by-product-like material. For Component 2, the highest E x /E m wavelength pairs
were found at 240/420, 280/420, and 320/420 nm in the three fluorescence peaks.
The component was reported to be basically characterized as humic-like matter.
Component 3 was observed at the highest E x /E m wavelength pair at 220/330 nm.
Regarded to derive from tryptophan protein-like materials, it was characterized by
the short-wavelength absorption.
It can be seen from the fluorescence intensity of F max that the tryptophan and tyrosine protein-like materials the dominated the fluorescence spectra of DOM. Through
the comparison of different AD processes, the component 2 in SHP-T and NSHP-T
exhibited lower F max values than those in the processes of a single stage. Due to the
increasing hydrolysis of the biorefractory DOMs and microbial activities under SHP,
protein-like component 1, together with component 3, was degraded significantly via
SHP-T. Basically, the FEMS-PFA results provided additional quantitative information demonstrating the distribution of the three fluorescent components identified
from the DOMs and the physiological responses of microbes to varying conditions
in their environment in the diverse AD processes (Jia et al. 2017a).
2.3.1.4 Microbial Community and Function
To analyze the metaproteome, the mixed liquor was extracted from reactors in three
different stages of SHPT (the peak stage of hydrogen production, peak methanogenic
stage, and late methanogenic stage included). They were represented as stage I, stage
II, and stage III, and in the time periods of 16–24 h, 276–324 h, and 420–450 h,
respectively (Fig. 2.20).
(1) Response relationship of identified proteins and biohydrogen production
According to the classic theory of hydrogen production from microorganisms, the
pathway of hydrogen production applies pyruvic acid as either a direct or indirect
electron donor. As shown in Fig. 2.21, the theory involves production of hydrogen
via decarboxylation of pyruvic acid and decomposition of formic acid. Another vital
theory of hydrogen production is the proposed NADH/NAD
+ equilibrium regulation.
Pyruvate, as one of the intermediates in the basic metabolism of microorganisms,
can be transferred among fats, sugar, and amino acids via the tricarboxylic acid and
acetyl-CoA cycles. As another critical precursor metabolite, acetyl-CoA is generated
through the oxidative decarboxylation of pyruvate (Fig. 2.21).
It is uncovered that the identified bacterial proteins pertained to production of
biohydrogen in pyruvate metabolism and glycolysis/gluconeogenesis are basically
demonstrated by the existence of the following substances: (i) the E1 component
2 High-Efficient Anaerobic Fermentation Technology of Organic …
E x /E m wavelength pair of 225/340 and 280/340 nm. It was a combination of tyrosine protein-like and tryptophan materials according to the result. The main peak at
280/340 nm and identified in Component 1 refers to the attributes of soluble microbial by-product-like material. For Component 2, the highest E x /E m wavelength pairs
were found at 240/420, 280/420, and 320/420 nm in the three fluorescence peaks.
The component was reported to be basically characterized as humic-like matter.
Component 3 was observed at the highest E x /E m wavelength pair at 220/330 nm.
Regarded to derive from tryptophan protein-like materials, it was characterized by
the short-wavelength absorption.
It can be seen from the fluorescence intensity of F max that the tryptophan and tyrosine protein-like materials the dominated the fluorescence spectra of DOM. Through
the comparison of different AD processes, the component 2 in SHP-T and NSHP-T
exhibited lower F max values than those in the processes of a single stage. Due to the
increasing hydrolysis of the biorefractory DOMs and microbial activities under SHP,
protein-like component 1, together with component 3, was degraded significantly via
SHP-T. Basically, the FEMS-PFA results provided additional quantitative information demonstrating the distribution of the three fluorescent components identified
from the DOMs and the physiological responses of microbes to varying conditions
in their environment in the diverse AD processes (Jia et al. 2017a).
2.3.1.4 Microbial Community and Function
To analyze the metaproteome, the mixed liquor was extracted from reactors in three
different stages of SHPT (the peak stage of hydrogen production, peak methanogenic
stage, and late methanogenic stage included). They were represented as stage I, stage
II, and stage III, and in the time periods of 16–24 h, 276–324 h, and 420–450 h,
respectively (Fig. 2.20).
(1) Response relationship of identified proteins and biohydrogen production
According to the classic theory of hydrogen production from microorganisms, the
pathway of hydrogen production applies pyruvic acid as either a direct or indirect
electron donor. As shown in Fig. 2.21, the theory involves production of hydrogen
via decarboxylation of pyruvic acid and decomposition of formic acid. Another vital
theory of hydrogen production is the proposed NADH/NAD
+ equilibrium regulation.
Pyruvate, as one of the intermediates in the basic metabolism of microorganisms,
can be transferred among fats, sugar, and amino acids via the tricarboxylic acid and
acetyl-CoA cycles. As another critical precursor metabolite, acetyl-CoA is generated
through the oxidative decarboxylation of pyruvate (Fig. 2.21).
It is uncovered that the identified bacterial proteins pertained to production of
biohydrogen in pyruvate metabolism and glycolysis/gluconeogenesis are basically
demonstrated by the existence of the following substances: (i) the E1 component