Aspergillus sojae

{{Short description|Species of fungus}}

{{Speciesbox

| image = Shoyukoji.jpg

| image_caption = Soy sauce koji consisting of soy bean and wheat cultured with Aspergillus sojae

| genus = Aspergillus

| species = sojae

| authority = Sakag. et K.Yamada ex Murak. 1971

| synonyms = Aspergillus sojae Sakag. & K. Yamada 1944

Aspergillus parasiticus f. sojae (Sakag. & K. Yamada) Nehira 1957

Aspergillus parasiticus var. sojae (Sakag. & K. Yamada) Wicklow 1983

Aspergillus flavus var. sojae (Sakag. & K. Yamada ex Murak.)

| subdivision_ranks = Varieties

| subdivision = Aspergillus sojae var. gymnosardae

}}

Aspergillus sojae is a species of fungus in the genus Aspergillus.

In Japan, it is used to make the ferment (kōji) of soy sauce, miso, mirin, and other lacto-fermented condiments such as tsukemono. Soy sauce condiment is produced by fermenting soybeans with A. sojae,{{cite book |first1=Michael J. |last1=Leboffe |first2=Burton |last2=Pierce |title=Microbiology: Laboratory Theory and Application |url=https://books.google.com/books?id=9Nn7PAAACAAJ |date=2006 |publisher=Morton |isbn=978-0-89582-708-1 |edition=2nd |page=317}} along with water and salt.

Glyceollins, molecules belonging to the pterocarpans, are found in the soybean (Glycine max) and have been found to have an antifungal activity against A. sojae.{{cite journal | vauthors = Kim HJ, Suh HJ, Lee CH, Kim JH, Kang SC, Park S, Kim JS | title = Antifungal activity of glyceollins isolated from soybean elicited with Aspergillus sojae | journal = Journal of Agricultural and Food Chemistry | volume = 58 | issue = 17 | pages = 9483–7 | date = September 2010 | pmid = 20666365 | doi = 10.1021/jf101694t }}

Aspergillus sojae contains 10 glutaminase genes. The glutaminase enzyme in A. sojae is important to the taste of the soy sauce that it produces.{{cite journal | vauthors = Ito K, Hanya Y, Koyama Y | title = Purification and characterization of a glutaminase enzyme accounting for the majority of glutaminase activity in Aspergillus sojae under solid-state culture | journal = Applied Microbiology and Biotechnology | volume = 97 | issue = 19 | pages = 8581–90 | date = October 2013 | pmid = 23339014 | doi = 10.1007/s00253-013-4693-4 | s2cid = 16513388 }}

An experiment was conducted using the genome sequencing of A. sojae. Strain NBRC 4239 had been isolated from the koji used to prepare Japanese soy sauce. The sequencing technology was used to investigate the genome with respect to enzymes and secondary metabolites in comparison with other Aspergillus species sequenced. The A. sojae NBRC4239 genome data will be useful to characterize functional features of the koji molds used in Japanese industries.{{cite journal | vauthors = Sato A, Oshima K, Noguchi H, Ogawa M, Takahashi T, Oguma T, Koyama Y, Itoh T, Hattori M, Hanya Y | title = Draft genome sequencing and comparative analysis of Aspergillus sojae NBRC4239 | journal = DNA Research | volume = 18 | issue = 3 | pages = 165–76 | date = June 2011 | pmid = 21659486 | pmc = 3111232 | doi = 10.1093/dnares/dsr009 }}