The Mycobiota of Air Inside and Outside the Meju Fermentation Room and the Origin of Meju Fungi

Abstract

The fungi on Meju are known to play an important role as degrader of macromolecule of soybeans. In order to elucidate the origin of fungi on traditional Meju, mycobiota of the air both inside and outside traditional Meju fermentation rooms was examined. From 11 samples of air collected from inside and outside of 7 Meju fermentation rooms, 37 genera and 90 species of fungi were identified. In outside air of the fermentation room, Cladosporium sp. and Cladosporium cladosporioides were the dominant species, followed by Cladosporium tenuissimum, Eurotium sp., Phoma sp., Sistotrema brinkmannii, Alternaria sp., Aspergillus fumigatus, Schizophyllum commune, and Penicillium glabrum. In inside air of the fermentation room, Cladosporium sp., Aspergillus oryzae, Penicillium chrysogenum, Asp. nidulans, Aspergillus sp., Cla. cladosporioides, Eurotium sp., Penicillium sp., Cla. tenuissimum, Asp. niger, Eur. herbariorum, Asp. sydowii, and Eur. repens were collected with high frequency. The concentrations of the genera Aspergillus, Eurotium, and Penicillium were significantly higher in inside air than outside air. From this result and those of previous reports, the origin of fungi present on Meju was inferred. Of the dominant fungal species present on Meju, Lichtheimia ramosa, Mucor circinelloides, Mucor racemosus, and Scopulariopsis brevicaulis are thought to be originated from outside air, because these species are not or are rarely isolated from rice straw and soybean; however, they were detected outside air of fermentation room and are species commonly found in indoor environments. However, Asp. oryzae, Pen. polonicum, Eur. repens, Pen. solitum, and Eur. chevalieri, which are frequently found on Meju, are common in rice straw and could be transferred from rice straw to Meju. The fungi grow and produce abundant spores during Meju fermentation, and after the spores accumulate in the air of fermentation room, they could influence mycobiota of Meju fermentation in the following year. This could explain why concentrations of the genera Aspergillus, Eurotium, and Penicillium are much higher inside than outside of the fermentation rooms.

Full text

258
Mycobiology
The Mycobiota of Air Inside and Outside the
Meju Fermentation Room and the Origin of Meju
Fungi
Dae-Ho Kim , Sun-Hwa Kim , Soon-wo Kwon , Jong-Kyu Lee and Seung-Beom Hong *
Korean Agricultural Culture Collection, Agricultural Microbiology Division, National Academy of Agricultural Science, Rural Development
Administration, Wanju 55365, Korea
Tree Pathology and Mycology Laboratory, Division of Forest Environment Protection, Kangwon National University, Chuncheon
24341, Korea
Abstract The fungi on Meju are known to play an important role as degrader of macromolecule of soybeans. In order to
elucidate the origin of fungi on traditional Meju, mycobiota of the air both inside and outside traditional Meju fermentation
rooms was examined. From 11 samples of air collected from inside and outside of 7 Meju fermentation rooms, 37 genera and 90
species of fungi were identified. In outside air of the fermentation room, Cladosporium sp. and Cladosporium cladosporioides
were the dominant species, followed by Cladosporium tenuissimum, Eurotium sp., Phoma sp., Sistotrema brinkmannii, Alternaria
sp., Aspergillus fumigatus, Schizophyllum commune, and Penicillium glabrum. In inside air of the fermentation room, Cladosporium
sp., Aspergillus oryzae, Penicillium chrysogenum, Asp. nidulans, Aspergillus sp., Cla. cladosporioides, Eurotium sp., Penicillium sp.,
Cla. tenuissimum, Asp. niger, Eur. herbariorum, Asp. sydowii, and Eur. repens were collected with high frequency. The
concentrations of the genera Aspergillus, Eurotium, and Penicillium were significantly higher in inside air than outside air. From this
result and those of previous reports, the origin of fungi present on Meju was inferred. Of the dominant fungal species present on
Meju, Lichtheimia ramosa, Mucor circinelloides, Mucor racemosus, and Scopulariopsis brevicaulis are thought to be originated from
outside air, because these species are not or are rarely isolated from rice straw and soybean; however, they were detected
outside air of fermentation room and are species commonly found in indoor environments. However, Asp. oryzae, Pen.
polonicum, Eur. repens, Pen. solitum, and Eur. chevalieri, which are frequently found on Meju, are common in rice straw and
could be transferred from rice straw to Meju. The fungi grow and produce abundant spores during Meju fermentation, and after
the spores accumulate in the air of fermentation room, they could influence mycobiota of Meju fermentation in the following
year. This could explain why concentrations of the genera Aspergillus, Eurotium, and Penicillium are much higher inside than
outside of the fermentation rooms.
Keywords Air, Fungi, Meju, Mycobiota, Origin
Meju is the important raw material for traditional Korean
Jangryu (the singular form, Jang) such as Ganjang, Doenjang,
and Gochujang [1]. Jangryu are useful and important sauces
in Korean cuisine. Moreover, Jangryu have been reported
to have health benefits such as antioxidative activity,
antithrombotic effects, cholesterol-lowering effects, mutation
suppression effects, and antitumor activities [2]. The taste
and quality of Jangryu are decided by the Meju used to
make them [3]. Various microorganisms are associated with
Meju fermentation, because traditional Meju is naturally
fermented [3]. In particular, fungi, which produce various
enzymes and degrade macromolecules in soybeans, are
important microorganisms in Meju fermentation [3, 4].
The fungi Aspergillus oryzae, Eurotium chevalieri, E. repens,
Lichtheimia ramosa, Mucor circinelloides, M. racemosus,
Penicillium polonicum, P. s o l i t um , and Scopulariopsis brevicaulis
occur commonly on Meju [4-8].
In this study, we investigated the origins of the fungi on
traditional Meju fermentation. This knowledge would help to
control of fungi that are present during Meju fermentation,
as some fungi on Meju are helpful for fermentation, but
Research Article
Mycobiology 2015 September, 43(3): 258-265
http://dx.doi.org/10.5941/MYCO.2015.43.3.258
pISSN 1229-8093 • eISSN 2092-9323
© The Korean Society of Mycology
*Corresponding author
E-mail: funguy@korea.kr
Received August 18, 2015
Revised August 31, 2015
Accepted September 6, 2015
This is an Open Access article distributed under the terms of the
Creative Commons Attribution Non-Commercial License (http://
creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted
non-commercial use, distribution, and reproduction in any medium,
provided the original work is properly cited.

The Mycobiota of Air Inside and Outside the Meju Fermentation Room 259
others are simply contaminants or toxigenic [2, 9]. Possible
sources of the fungi on traditional Meju include rice straw,
soybeans, and the air inside and outside the fermentation
room. The fungi present on rice straw and soybean have
been previously reported [10, 11]. Therefore, the aims of
this study are to (1) identify the composition of the mycobiota
in the air both inside and outside Meju fermentation room;
(2) compare it with those of traditional Meju, rice straw,
and soybeans; and (3) presume the origin of the fungi on
traditional Meju.
MATERIALS AND METHDOS
Eleven air samples were collected from inside (the
fermentation room) and outside (surrounding Jang factory)
of 7 Meju fermentation rooms during November 2011,
before starting Meju production (Table 1). The samples
were collected using a MAS-100 Eco air sampler (Merck,
Darmstadt, Germany) with malt extract agar (MEA; for
general fungi), dichloran rose bengal chloramphenicol agar
(for general enumeration of fungi), dichloran 18% glycerol
agar (DG18; for xerophilic fungi), and tryptic soy agar (for
Ta b l e 1 . Information about and fungal concentrations of air samples from Jang factories
Jang factories Sampling
date
Total fungal concentrations
in outside air (CFU/m
3
)
Total fungal concentrations
in inside air (CFU/m
3
)
Label Geological location Fermenting room type
GBC Gyeongbuk, Chilgok Room (farm village) 01 Dec 2011 0,201 2,611
GGI Gyeonggi, Icheon Room (farm village) 28 Nov 2011 0,401 1,425
GGY Gyeonggi, Yongin Greenhouse (farm village) 28 Nov 2011 0,686 -
JBB Jeonbuk, Buan Room (fishing village) 29 Nov 2011 0,050 1,322
JBSd Jeonbuk, Sunchang Room (town) 30 Nov 2011 - 1,358
JBSh Jeonbuk, Sunchang Yard (town) 30 Nov 2011 1,699 -
JND Jeonnam, Damyang Storage (farm village) 29 Nov 2011 1,380 0,902
Ta b l e 2 . List of fungal species from air of Meju fermentation room with their concentration in air
Fungal species KACC No. Sequence No.
a
Outside air Inside air
No. of
factories
b
Total concentrations
c
(CFU/m
3
)
No. of
factories
b
Total c o ncent r ation s
c
(CFU/m
3
)
Acremonium 10,010 - -
A. implicatum 47372 RDA0043336 1 0,010 - -
Alternaria 30,112 2 0,072
Alternaria sp. 47373 RDA0043364 3 0,112 2 0,072
Arthrinium 30,052 2 0,012
A. sacchari 47374 RDA0043363 3 0,042 2 0,012
Arthriniu m sp. 47375 RDA0043362 1 0,010 - -
Aspergillus 40,156 5 3,274
A. caesiellus 47377 RDA0043360 - - 1 0,020
A. creber 47378 RDA0043359 - - 1 0,002
A. fumigatus 47379 RDA0043358 2 0,112 1 0,002
A. jensenii 47380 RDA0043357 - - 2 0,030
A. nidulans 47382 RDA0043355 - - 1 0,450
A. niger 47383 RDA0043354 1 0,00340,292
A. ochlaceus 47384 RDA0043353 - - 1 0,020
A. oryzae 47385 RDA0043352 2 0,003 4 1,396
A. restrictus 47386 RDA0043351 - - 1 0,010
A. sclerotiorum 47387 RDA0043350 1 0,022 2 0,070
the genus Scopulariopsis). The air sampler put on the central
floor of fermentation room or on the ground outside the
Jang factory. And, 50 L, 100 L, and 500 L of air were collected
from inside of fermentation room and 100 L, 500 L, and
1,000 L of air were collected from the outside of Jang
factory. The plates were incubated at 25
o
C in the dark for
3~5 days. The colonies grown on each plate were counted,
and the average fungal concentrations of each plate were
expressed as colony forming units per cubic meter (CFU/
m
3
). The fungi grown on media were transferred into new
MEA or DG18 media. After incubation for several days,
the fungi were examined by light microscope for simple
identification, transferred into MEA or DG18 slant for
further examination, and then maintained at 4
o
C.
Molecular and morphological characteristics were used
to identify the fungi via methods previously described in
Kim et al. [11].
RESULTS AND DISCUSSION
As determined from 11 air samples from 7 Jang factories,
the average concentrations of fungi inside and outside

260 Kim et al.
Ta b l e 2 . Continued
Fungal species KACC No. Sequence No.
a
Outside air Inside air
No. of
factories
b
Total concentrations
c
(CFU/m
3
)
No. of
factories
b
Total c o ncent r ation s
c
(CFU/m
3
)
A. steynii 47388 RDA0043349 - - 2 0,130
A. sydowii 47389 RDA0043348 1 0,00230,250
A. tubingensis 47391 RDA0043346 2 0,0310,010
A. westerdijkiae 47394 RDA0043343 1 0,011 - -
A. versicolor 47392 RDA0043345 - - 2 0,160
Aspergillus sp. 47393 RDA0043344 - - 3 0,432
Beauveria 10,010 3 0,050
B. bassiana 47395 RDA0043342 1 0,010 3 0,050
Bionectria 10,00210,012
B. ochroleuca 47396 RDA0043341 1 0,00210,002
Bionectria sp. 47397 RDA0043340 - - 1 0,010
Bjerkandera 20,020 3 0,130
B. adusta 47398 RDA0043339 2 0,020 3 0,130
Ceriporia 20,011 - -
C. lacerata 47399 RDA0043338 2 0,011 - -
Chaetomium 10,040 2 0,022
C. globosum 47400 RDA0043337 1 0,040 2 0,022
Cladosporium 5 3,426 5 3,000
C. cladosporioides 47402 RDA0043391 1 1,360 2 0,380
C. pseudocladosporioides 47403 RDA0043390 1 0,008- -
C. tenuissimum 47405 RDA0043388 1 0,490 1 0,310
Cladosporium sp. 47404 RDA0043389 5 1,568 5 2,310
Cochliobolus 10,00120,012
C. miyabeanus 47406 RDA0043387 1 0,00110,010
Cochliobolus sp. 47407 RDA0043386 - - 1 0,002
Coprinellus --10,020
C. radians 47408 RDA0043385 - - 1 0,010
Coprinellus sp. 47409 RDA0043384 - - 1 0,010
Curvularia 10,001- -
C. intermedia 47410 RDA0043383 1 0,001- -
Epicoccum 40,031 2 0,032
E. nigrum 47412 RDA0043381 3 0,026 2 0,012
Epicoccum sp. 47413 RDA0043380 1 0,00510,020
Eurotium 50,411 5 0,850
E. chevalieri 47414 RDA0043379 1 0,030 1 0,010
E. herbariorum 47415 RDA0043378 2 0,054 2 0,280
E. repens 47417 RDA0043376 2 0,018 3 0,200
Eurotium sp. 4 0,309 5 0,360
Fusarium 50,084 4 0,120
F. acu m inat u m 47419 RDA0043374 - - 1 0,020
F. asi a t icum 47420 RDA0043373 4 0,043 2 0,080
F. pro l ife r a tum 47422 RDA0043371 1 0,010 1 0,020
Fusarium sp. 47421 RDA0043372 2 0,031 - -
Irpex --10,020
I. lacteus 47423 RDA0043370 - - 1 0,020
Isaria --10,020
I. fumosorosea 47424 RDA0043369 - - 1 0,020
Lecanicillium 10,010 2 0,030
L. psalliotae 47425 RDA0043368 1 0,010 2 0,030
Lichtheimia --10,002
Lichtheimia sp. 47426 RDA0043367 - - 1 0,002
Microsphaeropsis 10,010 - -
Microsphaeropsis sp. 47427 RDA0043366 1 0,010 - -
Mucor 10,00220,004
M. circinelloides 47428 RDA0043365 1 0,002- -
M. circinelloides/racemosus 47430 RDA0043434 - - 1 0,002
M. racemosus 47431 RDA0043433 - - 1 0,002

The Mycobiota of Air Inside and Outside the Meju Fermentation Room 261
Ta b l e 2 . Continued
Fungal species KACC No. Sequence No.
a
Outside air Inside air
No. of
factories
b
Total concentrations
c
(CFU/m
3
)
No. of
factories
b
Total c o ncent r ation s
c
(CFU/m
3
)
Penicillium 40,291 5 1,820
P. a t r a m e nt o s um 47432 RDA0043432 - - 1 0,010
P. c h r ys og e nu m complex 47434 RDA0043430 - - 2 0,976
P. c i t r in u m 47435 RDA0043429 - - 1 0,020
P. c r us t o su m 47436 RDA0043428 - - 1 0,180
P. g l a b r um 47438 RDA0043426 2 0,100 3 0,110
P. g l a n di c ol a 47439 RDA0043425 1 0,010 - -
P. h e r q u ei 47440 RDA0043424 1 0,001- -
P. m a l a ca e ns e 47441 RDA0043423 - - 1 0,022
P. ochrochloron 47442 RDA0043422 1 0,090 - -
P. o x a l ic u m 47443 RDA0043421 - - 1 0,010
P. p a r a h er q u ei 47445 RDA0043419 - - 1 0,010
P. p a x il l i 47446 RDA0043418 1 0,002- -
P. p o l o ni c um 47447 RDA0043417 - - 1 0,008
P. r a m u l o su m 47448 RDA0043416 - - 1 0,002
P. s c l er o t io r um 47449 RDA0043415 - - 1 0,010
P. simplicissimum 47450 RDA0043414 - - 1 0,010
P. s o l i tu m 47451 RDA0043413 - - 1 0,010
P. s t e c k ii 47452 RDA0043412 1 0,030 1 0,060
P. t h o m i i 47453 RDA0043411 - - 1 0,040
P. w e s t li n g ii 47454 RDA0043410 1 0,030 - -
Penicillium sp. 2 0,028 4 0,342
Peniophora --10,040
P. a u r a n t i ac a 47455 RDA0043409 - - 1 0,040
Periconia --10,010
Periconia sp. 47457 RDA0043407 - - 1 0,010
Pestalotiopsis 10,00120,022
Pestalotiopsis sp. 47458 RDA0043406 1 0,00120,022
Peziza --10,010
Peziza sp. 47459 RDA0043405 - - 1 0,010
Phlebiopsis --10,020
P. g i g an t e a 47460 RDA0043404 - - 1 0,020
Phoma 40,140 3 0,064
Phoma sp. 47461 RDA0043403 4 0,140 3 0,064
Phomopsis 10,008- -
Phomopsis sp. 47462 RDA0043402 1 0,008- -
Pichia --10,110
P. b u r to n i i 47463 RDA0043401 - - 1 0,110
Rhizopus 20,00320,022
R. microsporus 47464 RDA0043400 1 0,002- -
R. stolonifer 47465 RDA0043399 1 0,00110,020
Rhizopus sp. 47466 RDA0043398 - - 1 0,002
Schizophyllum 20,100 1 0,020
S. commune 47467 RDA0043397 2 0,100 1 0,020
Scopulariopsis 30,025 1 0,030
S. brevicaulis 47468 RDA0043396 3 0,025 1 0,030
Sistotrema 10,120 - -
S. brinkmannii 47469 RDA0043395 1 0,120 - -
Syncephalastrum --10,010
S. monosporum 47470 RDA0043394 - - 1 0,010
Talaromyces --10,010
Ta la r om y c es sp. 47471 RDA0043393 - - 1 0,010
a
The Rural Development Administration (RDA) numbers are DNA sequence accession numbers from the Korean Agricultural Culture
Collection (KACC). Readers can access the sequences at the KACC homepage (http://www.genebank.go.kr) using the corresponding
KACC numbers.
b
The numbers indicates factories from which the species were isolated from 6 (outside air) and 5 (inside air) factories.
c
The numbers indicates the sum of the maximum concentrations of each factory among concentrations on each media.

262 Kim et al.
Ta b l e 3 . List of fungi on Meju and their isolation frequencies from air of Meju fermentation room, rice straw, and soybeans
Scientific name Incidence
on Meju
a
Air of Meju fermentation room Rice straw
b
Soybeans
c
Outside air Inside air
No. of
factories
Maximum
isolation
frequency
(%)
No. of
factories
Maximum
isolation
frequency
(%)
No. of
factoreis
d
Total
concentration
(CFU/m
3
)
e
No. of
factoreis
d
Tot a l
concentration
(CFU/m
3
)
e
Aspergillus oryzae *** 20,003 4 1,396 10 31.9 7 07.2
Mucor circinelloides *** 10,002- -102.1 - -
Mucor racemosus *** --10,002- - - -
Penicillium polonicum *** --10,008511.8404.2
Eurotium repens *** 20,018 3 0,200 9 27.1 6 26.8
Scopulariopsis brevicaulis *** 30,025 1 0,030 - - - -
Penicillium solitum *** --10,010 2 00.7 - -
Eurotium chevalieri *** 10,030 1 0,010 12 25.0 303.2
Lichtheimia ramosa *** ----201.4 2 03.8
Fusarium asiaticum ** 40,043 2 0,080 11 56.3 1 00.2
Penicillium paneum ** --------
Eurotium amstelodami ** ----715.3100.2
Aspergillus niger ** 1340,292 7 09.7 - -
Penicillium roqueforti ** ------100.2
Paecilomyces variotii ** --------
Cladosporium tenuissimum ** 10,\490 1 0,310 1 06.9 2 23.8
Rhizopus stolonifer ** 10,00110,020 1 00.7 - -
Eurotium herbariorum ** 20,054 2 0,280 5 22.9 8 44.0
Penicillium crustosum ** --10,180 - - - -
Penicillium bialowiezense ** --------
Eurotium rubrum ** ----516.0 303.8
Lichtheimia corymbifera ** ----313.9100.2
Aspergillus acidus ** --------
Aspergillus tamarii ** ----105.6 - -
Aspergillus fumigatus ** 20,112 1 0,002304.2 1 00.2
Aspergillus flavus ** ----203.5 - -
Rhizopus delemar ** --------
Scopulariopsis candida ** --------
Cladosporium cladosporioides ** 11,360 20,380 10 48.6 1 9.
Lichtheimia ornata ** --------
Aspergillus tubingensis ** 20,00210,010 10 37.5 2 00.8
Rhizomucor pusillus ** ----101.4 - -
Mucor mucedo ** --------
Aspergillus nidulans ** --1
0,450 7 08.3 1 00.4
Penicillium commune ** --------
Penicillium palitans ** --------
Aspergillus sydowii ** 10,00230,220 4 04.9 4 03.4
Monascus ruber ** --------
Geotrichum silvicola ** --------
Aspergillus versicolor ** --20,160 2 06.3 4 05.6
Neurospora intermedia ** --------
Aspergillus ochlaceus ** --10,020 3 04.2 4 02.6
Fusarium sp. ** 20,031 - - 9 05.6 5 12.8
Penicillium chrysogenum ** --20,976 1 00.7 2 01.2
Mucor lusitanicus ** --------
Rhizopus oryzae ** ----204.9 - -
Epicoccum nigrum ** 30,026 2 0,012 3 14.6 1 00.2
Eurotium echinulatum ** ----102.8 3 00.8
Fusarium cf. incarnatum *----411.1202.2
Fusarium graminiarum *--------
Mucor hiemalis *--------
Penicillium brevicompactum *----201.4 - -

The Mycobiota of Air Inside and Outside the Meju Fermentation Room 263
Ta b l e 3 . Continued
Scientific name Incidence
on Meju
a
Air of Meju fermentation room Rice straw
b
Soybeans
c
Outside air Inside air
No. of
factories
Maximum
isolation
frequency
(%)
No. of
factories
Maximum
isolation
frequency
(%)
No. of
factoreis
d
Total
concentration
(CFU/m
3
)
e
No. of
factoreis
d
Tot a l
concentration
(CFU/m
3
)
e
Aspergillus cibarius *------100.8
Cladosporium velox *----203.5 - -
Syncephalastrum racemosum *--10,010 2 03.5 1 00.2
Aspergillus candidus *--------
Eurotium tonophilum *------14.
Penicillium coprohilum *--------
Penicillium steckii *10,030 1 0,060 4 14.6 5 06.6
Tr ic ho s po ro n sp. *--------
Aspergillus parasiticus *--------
Cladosporium sphaerospermum *----100.7 1 00.2
Paecilomyces formosus *--------
Penicillium expansum *------200.6
Penicillium oxalicum *--10,010 1 01.4 1 4.
Chaetomium cruentum *--------
Fusarium acuminatum *--10,020 1 04.2 - -
Penicillium carneum *--------
Penicillium cyclopium *------100.4
Phycomyces blakesleanus *--------
Cladosporium varians *--------
Allantophomopsis cf. lycopodina *--------
Alternar ia sp. *30,112 2 0,072 6 05.6 7 12.0
Arthrinium phaeospermum *----302.1 1 03.8
Aspergillus tritici *--------
Aspergillus westerdijkiae *10,011 - - 3 06.3 3 6.
Botryotinia fuckeliana *--------
Botrytis sp. *------100.2
Chaetomium sp. *----304.9 2 00.6
Cladosporium funiculosum *--------
Cladosporium fusiforme *----100.7 - -
Cladosporium perangustum *--------
Fusarium fujikuroi *----59.519.6
Fusarium thapsinum *--------
Geotrichum sp. *--------
Lichtheimia hyalospora *--------
Mucor fragilis *--------
Mucor irregular is *--------
Neurospora sitophila *--------
Penicillium chermesinum *--------
Penicillium glabrum *20,100 3 0,110 2 00.7 - -
Penicillium griseofulvum *--------
Penicillium hispanicum *----204.2 - -
Penicillium nordicum *--------
Penicillium olsonii *--------
Phoma sp. *40,140 3 0,064 6 13.9 5 01.8
Streptobotrys cf. streptothrix *--------
Ulocladium sp. *--------
a
The species were isolated from Meju, with ***high frequency, **medium frequency, or *low frequency.
b
The number of factories indicates factories from which the species were isolated from 12 factories. Maximum isolation frequency
indicates maximum isolation frequency (among 144 pieces of rice straw) among 9 different isolation conditions [8].
c
The number of factories indicates factories from which the species were isolated from 10 factories. Maximum isolation frequency
indicates maximum isolation frequency (among 500 kernels) of untreated soybeans among 3 different media [9].
d
The number indicates factories from which the species were isolated from 6 (outside air) and 5 (inside air) factories.
e
The numbers indicate the sum of the maximum concentrations of each factory among concentrations on each media.

264 Kim et al.
Meju fermentation rooms were 1,524 CFU/m
3
and 736
CFU/m
3
(Table 1), respectively, and they were identified into
37 genera and 90 species (Table 2). The fungal concentration
in inside air of Meju fermentation room is similar or
lower than that of green area in Seoul, Korea (average,
1,892 CFU/m
3
in winter) [12] and is similar to that of low
clean zone of other food product manufacturing plants
(average, 2,600 CFU/m
3
) [13]. In this study, there was
no significant difference of mycobiota according to Jang
factories.
In the 6 outside air samples, 27 genera and 50 species
were found (Table 2). The concentration of the genus
Cladosporium was significantly high, followed by those
of Eurotium, Penicillium, Aspergillus, Sistotrema, and
Schizophyllum were followed (Table 2). Cla. cladosporioides
and Cladosporium sp. were the dominant species, followed
by Cla. tenuissimum, Eurotium sp., Sistotrema brinkmannii,
Asp. fumigatus, Schizophyllum commune, Phoma sp., and
Alternaria sp. However, Cla. tenuissimum, Sis. brinkmannii,
Asp. fumigatus, and Sch. commune were detected only in 1
or 2 factories. In addition, almost all the other fungi except
Arthrinium sacchari, Epicoccum nigrum, and S. brevicaulis,
which were detected in 3 Jang factories, were also detected
only in 1 or 2 factories.
Of the 32 genera and 72 species from the 5 inside air
samples, the genus Aspergillus, Cladosporium, Penicillium,
and Eurotium were collected with high concentrations
(Table 2). A. oryzae and Cladosporium sp. were the dominant
species and were detected in 5 and 4 factories, respectively.
In addition, Pen. chrysogenum (found in 2 factories),
C. cladosporioides (2), Asp. niger (4), Eur. herbariorum
(2), Aspergillus sp. (3), Penicillium sp. (4), and Asp.
sydowii (3) were frequently detected in inside air of the
fermentation rooms. Although Eur. repens, Pen. glabrum,
Phoma sp., Bjerkandera adusta, and Beauveria bassiana were
infrequently detected in inside air of the fermentation
rooms, they were detected in 3 factories. The other species
detected in inside air samples were detected in only 1 or 2
factories.
The mycobiota of outside and inside air of the fermentation
rooms differed (Table 2), and fungi detected from inside
air were more diverse. Seventy-two species were detected
from the inside air, whereas 50 species were detected from
the outside air. The species belong to the genus Alternaria,
Arthrinium, Chaetomium, Cladosporium, Phoma, and
Schizophyllum were present in higher concentrations in
outside air than in inside air. In particular, Alternaria,
Arthrinium, and Cladosporium were significantly higher.
Therefore, these fungi present in the inside air may have
come in from outside when the inside air was ventilated.
However, many fungi belonging to the genus Aspergillus,
Penicillium, and Eurotium were frequently detected in
inside air but were rarely or not detected in outside air.
These observations indicate that these fungi were not
influenced by the outside mycobiota but may have been
influenced by previous Meju fermentation, because they
frequently occurred on Meju.
The species, Asp. oryzae, M. circinelloides, M. racemosus,
Pen. polonicum, Eur. repens, Scopulariopsis brevicaulis, Pen.
solitum, Eur. chevalieri, and L. ramosa were the main species
from Meju (Table 3). A. oryzae, P. p o l o n ic u m , E. repens, P.
solitum, E. chevalieri, and F. a s i a t icum are detected on rice
straw with high frequency but are rarely isolated from
outside air of Jang factories. Therefore, most of these could
be transferred from rice straw to Meju, and they grow and
produce abundant spores during Meju fermentation, and
then as their spores would accumulated inside air of
fermentation room, they could influence mycobiota of Meju
fermentation in the following year. This could explain why
concentrations of Aspergillus, Eurotium, and Penicillium in
inside air of Meju fermentation room is much higher than
those of outside air.
Lichtheimia ramosa, M. circinelloides, M. racemosus, and
S. brevicaulis were rarely or not detected in rice straw and
soybean. However, they were detected from outside air
of Meju fermentation room, although their frequencies
were not high, and they are generally known as common
fungi in indoor environments [14]. Therefore, L. ramosa,
M. circinelloides, M. racemosus, and S. brevicaulis on Meju
might originate from outside (or inside) air of Meju
fermentation room.
In this study, all main species on Meju except L. ramosa
were detected both inside and outside of fermentation room.
However, L. ramosa is usually known as an indoor fungus
[14]. After all, Meju could be provided with almost fungi
from air in and out Meju fermentation room, which is
used for Meju fermentation for more than one time.
Rice straw comes into direct contact with soybeans in
Meju, and so the fungi on rice straw can move to Meju
and grow on it. Therefore, this has a great influence on
Meju mycobiota. Rice straw could provide Meju with useful
fungi for fermentation but also could provide unwanted fungi
such as Fusarium asiaticum. Traditional Meju fermentation
is composed of drying at a low temperature (low temperature
fermentation process) and fermenting at a high temperature
and humidity (high temperature fermentation process) [4].
F. asi a ticum usually originates from rice straw and grows
on it during fermentation at low temperatures. Therefore,
in order to avoid contamination of F. a s iati c u m , a method
could be developed to use rice straw only during high
temperature fermentation. Without rice straw, Meju might
be provided with main fungi from both inside and outside
of Meju fermentation room during the low temperature
fermentation process, if the fermentation room is used for
Meju fermentation more than once.
ACKNOWLEDGEMENTS
This work was partly supported by a research project (no.
PJ00866601) of the National Academy of Agricultural Science
(NAAS), Rural Development Administration, Republic of
Korea.

The Mycobiota of Air Inside and Outside the Meju Fermentation Room 265
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