title: Safety evaluation of filamentous fungi isolated from industrial doenjang koji.
abstract: A few starters have been developed and used for doenjang fermentation but often without safety evaluation. Filamentous fungi were isolated from industrial doenjang koji, and their potential for mycotoxin production was evaluated. Two fungi were isolated; one was more dominantly present (90%). Both greenish (SNU-G) and whitish (SNU-W) fungi showed 97% and 95% internal transcribed spacer sequence identities to Aspergillus oryzae/flavus, respectively. However, the SmaI digestion pattern of their genomic DNA suggested that both belong to A. oryzae. Moreover, both fungi had morphological characteristics similar to that of A. oryzae. SNU-G and SNU-W did not form sclerotia, which is a typical characteristic of A. oryzae. Therefore, both fungi were identified to be A. oryzae. In aflatoxin gene cluster analysis, both fungi had norB-cypA genes similar to that of A. oryzae. Consistent with this, aflatoxins were not detected in SNU-G and SNU-W using ammonia vapor, TLC, and HPLC analyses. Both fungi seemed to have a whole cyclopiazonic acid (CPA) gene cluster based on PCR of the maoA, dmaT, and pks-nrps genes, which are key genes for CPA biosynthesis. However, CPA was not detected in TLC and HPLC analyses. Therefore, both fungi seem to be safe to use as doenjang koji starters and may be suitable fungal candidates for further development of starters for traditional doenjang fermentation.
authors.affiliation: Department of Bio and Fermentation Convergence Technology, Kookmin University, Seoul 136-702, Republic of Korea.
authors.forename: Jin Hee
authors.initials: JH
authors.lastname: Lee
authors.forename: Eun Hye
authors.initials: EH
authors.lastname: Jo
authors.forename: Eun Jin
authors.initials: EJ
authors.lastname: Hong
authors.forename: Kyung Min
authors.initials: KM
authors.lastname: Kim
authors.forename: Inhyung
authors.initials: I
authors.lastname: Lee
mesh_terms: D001236:Aspergillus oryzae / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D016000:Cluster Analysis; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D005516:Food Microbiology; D059022:Food Safety; D005658:Fungi / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009183:Mycotoxins / Q000032:analysis / Q000235:genetics*; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer; D009183:Mycotoxins