What kind of microorganisms are present in Garbage-in?
There is no doubt that microorganisms are at work in compost,
but what kind of microorganisms are there?
In recent years, research into microorganisms has progressed with the development of analytical equipment,
but only a small proportion of microorganisms are known about their ecology.
We conducted a microbial analysis to find out what types of microorganisms are present,
even if we cannot identify the function of each individual microorganism.
We used a method called amplicon analysis to investigate the "Bacteria" and "Fungi" in Garbage-in compost.
Bacteria (phylum level)
*The numbers are in percentages. The bar graph on the right shows a small number of bacteria.
*The numbers in the text below are not included in the graph above,
but the bacterial names and numbers are listed from the original analysis data.
"Bacteria" are single-celled organisms that multiply by cell division.
Basically, they can multiply on their own if they have the nutrients,
which is very different from viruses.
The most common phylum in compost is the Proteobacteria (= Pseudomonas) ,
which accounts for about 45% of the total.
This phylum includes the Gammaproteobacteria (20.7%), Alphaproteobacteria (17.0%),
and Betaproteobacteria (2.5%). They are known as human intestinal bacteria.
The second most common phylum is the Actinomycetota.
This phylum includes the Actinobacteria (14.3%) and Acidimicrobiia (3.0%).
They are often introduced as soil microorganisms related to plant growth. The smell of compost is apparently due to these actinomycetes.
The third phylum, Bacteroidetes, contains the classes Sphingobacteria (5.8%) and Flavobacteriia (1.7%).
This phylum is also known as the main intestinal bacteria of humans,
but is also commonly found in the ocean and soil.
Fungi (phylum level)
"Fungi" includes single-celled yeasts and multicellular filamentous fungi with thread-like hyphae,
such as mushrooms and molds.
They are eukaryotes and some species have unique functions not found in prokaryotic bacteria,
and some are used in sake brewing and industrial enzyme production. *From "Introduction to Living Things" by Department of Chemistry, Faculty of Science, Hokkaido University
The Ascomycota phylum accounts for about 71% of the total.
This phylum includes the genera Candida (29.7%), Aspergillus (15.3%), Nectriaceae (13.7%), and Penicillium (2.2%).
The second phylum, Basidiomycota, includes the genera Trichosporon (4.4%) and Coprinopsis (1%).
Most of the third phylum, Zygomycota, is from the genus Rhizopus (4.3%).
* The above is the results of analysis by TechnoSuruga Laboratory Co., Ltd. in January 2022.
It is thought that the many microorganisms that enter the composter interact with each other to decompose the food waste.
Some of the same types of bacteria as pathogens are found, so hygiene must be taken into consideration.
