72
3 Bio-augmented Composting of Organic Wastes in Villages and Towns
3.3.1.2 Promotion Mechanism of Lignocelluloses-Degrading Microbial
Inoculants for Humification of Composts
By using metaproteomics method, the influence of inoculating mixed bacteria of lignocelluloses on structures and functions of bacterial and fungal communities in the
composting process of kitchen wastes was analyzed (Fig. 3.4). Moreover, the differences of metabolic pathways of carbohydrates during the composting were further
analyzed to thus further reveal the action mechanism of inoculants on microorganisms
in the composting process. Metaproteomics research showed that compared with the
group without being inoculated, after inoculating the cellulose-degrading microbial
inoculants, the proportion of bacteria in Pseudomonadales rose from 15.1 to 27.6%
while that of Bacilli decreased from 16.0 to 6.4%. Additionally, the proportion of
Eurotiomycete fungi increased to 32.8 from 10.8% while that in Saccharomycete
fungi reduced from 48.1 to 26.6%. Adding microbial inoculants showed an insignificant influence on the diversity of microbial community in composts while the number
of microbial communities varied. Moreover, Pseudomonadales became the predominant bacteria by replacing Bacilli while Eurotiomycetes was taken as predominant
fungus by replacing Saccharomycetes.
The metabolism of carbohydrates is the major metabolic type in the composting
process. After inoculating cellulose-degrading microbial inoculants, the bacteria in
Pseudomonadales (17) and Enterobacteriales (12), Actinomycetes (6) in Actinobacteria and fungi (9) in Eurotiomycetes were more than those of the control group. By
contrast, the numbers of Bacilli bacteria (10) and Saccharomycetes fungi (12) in the
control group were larger.
In carbohydrates, the degradation of lignocelluloses plays a crucial role in the composting process. As the main carbon sources, cellulose and hemicelluloses provide
energies for biotransformation and lignin is the important starting material during
the formation of humic acid. Nine lignocellulolytic enzymes were identified from the
experimental group (addition with microbial inoculants) and the control group. In the
experimental group with the addition of microbial inoculants, there were cellulase
(1) generated by Thermobifida spp., cellulase (4) and hemicellulase (1) produced
by fungi in Aspergillus (Eurotiomycetes), and ligninase (1) produced by fungi in
Melanocarpus (Sordariomycetes). The cellulase (1) generated by bacteria in Bacillus (Bacilli) and hemicellulase (1) produced by fungi in Aspergillus were detected
in the control group, as shown in Table 4.2. It indicated that during the experimental
process with addition of microbial inoculants, fungi in Aspergillus (Eurotiomycetes)
and Melanocarpus are the main microorganisms for degrading lignocelluloses in the
composting process while the Basidiomycota fungi are both weak in abundance and
activity.
As shown in Fig. 3.5, bacteria in Bacillales and Aspergillus spp. in microbial inoculants were the main microbial communities in which Aspergillus spp. can degrade
3 Bio-augmented Composting of Organic Wastes in Villages and Towns
3.3.1.2 Promotion Mechanism of Lignocelluloses-Degrading Microbial
Inoculants for Humification of Composts
By using metaproteomics method, the influence of inoculating mixed bacteria of lignocelluloses on structures and functions of bacterial and fungal communities in the
composting process of kitchen wastes was analyzed (Fig. 3.4). Moreover, the differences of metabolic pathways of carbohydrates during the composting were further
analyzed to thus further reveal the action mechanism of inoculants on microorganisms
in the composting process. Metaproteomics research showed that compared with the
group without being inoculated, after inoculating the cellulose-degrading microbial
inoculants, the proportion of bacteria in Pseudomonadales rose from 15.1 to 27.6%
while that of Bacilli decreased from 16.0 to 6.4%. Additionally, the proportion of
Eurotiomycete fungi increased to 32.8 from 10.8% while that in Saccharomycete
fungi reduced from 48.1 to 26.6%. Adding microbial inoculants showed an insignificant influence on the diversity of microbial community in composts while the number
of microbial communities varied. Moreover, Pseudomonadales became the predominant bacteria by replacing Bacilli while Eurotiomycetes was taken as predominant
fungus by replacing Saccharomycetes.
The metabolism of carbohydrates is the major metabolic type in the composting
process. After inoculating cellulose-degrading microbial inoculants, the bacteria in
Pseudomonadales (17) and Enterobacteriales (12), Actinomycetes (6) in Actinobacteria and fungi (9) in Eurotiomycetes were more than those of the control group. By
contrast, the numbers of Bacilli bacteria (10) and Saccharomycetes fungi (12) in the
control group were larger.
In carbohydrates, the degradation of lignocelluloses plays a crucial role in the composting process. As the main carbon sources, cellulose and hemicelluloses provide
energies for biotransformation and lignin is the important starting material during
the formation of humic acid. Nine lignocellulolytic enzymes were identified from the
experimental group (addition with microbial inoculants) and the control group. In the
experimental group with the addition of microbial inoculants, there were cellulase
(1) generated by Thermobifida spp., cellulase (4) and hemicellulase (1) produced
by fungi in Aspergillus (Eurotiomycetes), and ligninase (1) produced by fungi in
Melanocarpus (Sordariomycetes). The cellulase (1) generated by bacteria in Bacillus (Bacilli) and hemicellulase (1) produced by fungi in Aspergillus were detected
in the control group, as shown in Table 4.2. It indicated that during the experimental
process with addition of microbial inoculants, fungi in Aspergillus (Eurotiomycetes)
and Melanocarpus are the main microorganisms for degrading lignocelluloses in the
composting process while the Basidiomycota fungi are both weak in abundance and
activity.
As shown in Fig. 3.5, bacteria in Bacillales and Aspergillus spp. in microbial inoculants were the main microbial communities in which Aspergillus spp. can degrade