title: Characterization ofAspergillus sojaeIsolated from Meju, Korean Traditional Fermented Soybean Brick.
abstract: Initially, we screened 18Aspergillus sojae-like strains fromAspergillusspp. isolated from meju (Korean traditional fermented soybean brick) according to their morphological characteristics. Because members ofAspergillussectionFlaviare often incorrectly identified because of their phylogenetic similarity, we re-identified these strains at the morphological and molecular genetic levels. Fourteen strains were finally identified asA. sojae. The isolates produced protease and α-amylase with ranges of 2.66-10.64 and 21.53-106.73 unit/g-initial dry substrate (U/g-IDS), respectively, which were equivalent to those of the koji (starter mold) strains employed to produce Japanese soy sauce. Among the isolates and Japanese koji strains, strains SMF 127 and SMF 131 had the highest leucine aminopeptidase (LAP) activities at 6.00 and 6.06 U/g-IDS, respectively. LAP plays an important role in flavor development because of the production of low-molecular-weight peptides that affect the taste and decrease bitterness. SMF 127 and SMF 131 appeared to be non-aflatoxigenic because of a termination point mutation inaflRand the lack of the polyketide synthase gene found in otherA. sojaestrains. In addition, SMF 127 and SMF 131 were not cyclopiazonic acid (CPA) producers because of the deletion ofmaoA,dmaT, andpks/nrps, which are involved in CPA biosynthesis. Therefore,A. sojaestrains such as SMF 127 and SMF 131, which have high protease and LAP activities and are free of safety issues, can be considered good starters for soybean fermentations, such as in the production of the Korean fermented soybean products meju, doenjang, and ganjang.
authors.affiliation: Department of Bio and Fermentation Convergence Technology, BK21 PLUS Project, Kookmin University, Seoul 02707, Republic of Korea.
authors.forename: Kyung Min
authors.initials: KM
authors.lastname: Kim
authors.affiliation: Department of Bio and Fermentation Convergence Technology, BK21 PLUS Project, Kookmin University, Seoul 02707, Republic of Korea.
authors.forename: Jaeho
authors.initials: J
authors.lastname: Lim
authors.affiliation: Sempio Fermentation Research Center, Sempio Foods Company, Chungcheongbukdo 28156, Republic of Korea.
authors.forename: Jae Jung
authors.initials: JJ
authors.lastname: Lee
authors.affiliation: Sempio Fermentation Research Center, Sempio Foods Company, Chungcheongbukdo 28156, Republic of Korea.
authors.forename: Byung-Serk
authors.initials: BS
authors.lastname: Hurh
authors.affiliation: Department of Bio and Fermentation Convergence Technology, BK21 PLUS Project, Kookmin University, Seoul 02707, Republic of Korea.
authors.forename: Inhyung
authors.initials: I
authors.lastname: Lee
mesh_terms: D000348:Aflatoxins; D001230:Aspergillus / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification* / Q000378:metabolism; D001231:Aspergillus flavus / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D005285:Fermentation; D005516:Food Microbiology; D005656:Fungal Proteins / Q000235:genetics; D007211:Indoles / Q000378:metabolism; D007931:Leucyl Aminopeptidase / Q000096:biosynthesis / Q000737:chemistry; D010447:Peptide Hydrolases / Q000096:biosynthesis; D010802:Phylogeny; D048630:Polyketide Synthases / Q000235:genetics / Q000378:metabolism; D045730:Soy Foods / Q000382:microbiology*; D014157:Transcription Factors / Q000235:genetics; D000516:alpha-Amylases / Q000096:biosynthesis
chemical_list: C113837:AFLR protein, Aspergillus; D000348:Aflatoxins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D007211:Indoles; D014157:Transcription Factors; D048630:Polyketide Synthases; D000516:alpha-Amylases; D010447:Peptide Hydrolases; D007931:Leucyl Aminopeptidase; C000543:cyclopiazonic acid
keywords: Aspergillus sojae; leucine aminopeptidase; protease; soybean fermentation; starter mold