(Mar.22-Sep.24, 2022, Nagoya University Museum)
Special Display 2
The scientific name for natto bacteria is Bacillus subtilis (natto). “Bacillus” comes from the Latin word for “rod” and “subtilis” from that for “elongate,” thus it means “elongated rod bacteria.” Since it indicates the strain used for fermenting natto, the proper noun (natto) follows Bacillus subtilis. The Japanese term for Bacillus subtilis as a species is kosokin, without specifying (natto) as the species or subspecies in its classification. In other words, from the point of view of the Japanese, Bacillus subtilis (natto) is a bit of a roundabout way of indicating one strain of kosokin used in natto production.
Thanks to advancements in molecular biology, we have become able to tie biological species with the information in their genome (complete DNA nucleotide sequences) and gain an understanding of them. The same holds for the classification of microorganisms. Prior to when DNA analysis became possible, however, they were classified according to the parameters including morphological features observed through microscopy, their function of utilization, spore formation, properties of their colonies, color, and production of metabolites with certain characteristics, along with their usefulness or harmfulness (pathogenicity) to humans. If natto had been eaten traditionally in Europe, natto bacteria might instead have been named Bacillus soyfermentum, expressing rod bacteria of fermenting soybeans.
Though called “natto bacteria” as noted above, outside of Japan, they are not well understood. However, with Thailand’s fermented soybean dish thua nao being called “Thai natto,” for example, the use of the word “natto” outside of Japan has been increasing bit by bit. Natto, the production of which became an early case of food industrialization, has become recognized as a name for other fermented foods in many other Asian nations that resemble natto.
Natto bacteria possess the ability to produce sticky substances (polymerized glutamate compounds) and a form of motility called “sliding.” Bacillus subtilis (natto) with these attributes are not difficult to find on rice straw and other plant leaves. Incidentally, there are people who do not like the smell or characteristic stickiness of natto. To produce natto for consumers such as these and businesses wishing to serve them, natto bacteria have been under development recently for reduced smell and stickiness. Non-sticky natto that can be used easily in processing or cooking is expected to lead to increased consumption through exports, use at nursing facilities and other applications.
* The English title has slightly been changed from the panel.
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