• Journal of Mushroom
• /
• v.6 no.1
• /
• pp.27-31
• /
• 2008

The optimization of submerged culture conditions for mycelial growth and exopolysaccharide (EPS) production in an edible mushroom Tremella fuciformis were studied in shake flasks and bioreactors. The temperature of $28^{\circ}C$ and pH 8 in the beginning of fermentation in agitated flasks was the most efficient condition to obtain maximum mycelial biomass and EPS. The optimal medium constituents were as follows (g l-1): glucose 20, tryptone 2, $KH_2PO_4$ 0.46, $K_2HPO_4$ 1 and $MgSO_4H_2O$ 0.5. The fungus was cultivated under various agitation and aeration conditions in a 5L stirred-tank bioreactor. The maximum cell mass and EPS production were obtained at a relatively high agitation speed of 200 rpm and at an aeration rate of 2 vvm. The flow behavior of the fermentation broth was Newtonian and the maximum apparent viscosity (35 cP) was observed at a highly aerated condition (2 vvm). The EPS productivity in an airlift reactor was higher than that in the stirred-tank reactor. The EPS was protein-bound polysaccharides consisted of mainly mannose, xylose, and fructose. The molecular weights of EPS were determined to be $1.3{\sim}1.5{\times}10^6$.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.9
• /
• pp.1527-1535
• /
• 2018

Bacterial strain BAS23 was isolated from rice field soil and identified as Bacillus amyloliquefaciens. Based on dual culture method results, the bacterium BAS23 exhibited potent in vitro inhibitory activity on mycelial growth against a broad range of dirty panicle fungal pathogens of rice (Curvularia lunata, Fusarium semitectum and Helminthosporium oryzae). Cell-free culture of BAS23 displayed a significant effect on germ tube elongation and mycelial growth. The highest dry weight reduction (%) values of C. lunata, H. oryzae and F. semitectum were 92.7%, 75.7%, and 68.9%, respectively. Analysis of electrospray ionization-mass spectrometry (ESI-MS) and $^1H$ nuclear magnetic resonance (NMR) spectroscopy revealed that the lipopeptides were iturin A with a C14 side chain (C14 iturinic acid), and a C15 side chain (C15 iturinic acid), which were produced by BAS23 when it was cultured in nutrient broth (NB) for 72 h at $30^{\circ}C$. BAS23, the efficient antagonistic bacterium, also possessed in vitro multiple traits for plant growth promotion and improved rice seedling growth. The results indicated that BAS23 represents a useful option either for biocontrol or as a plant growth-promoting agent.

• Journal of Microbiology and Biotechnology
• /
• v.30 no.4
• /
• pp.561-570
• /
• 2020

This study was designed to synthesize triglycerol monolaurate (TGML) with Lipozyme 435 as the catalyst, and explore its effects on the growth of Aspergillus parasiticus (A. parasiticus) and Aspergillus flavus (A. flavus) and the secretion of aflatoxin b1. The highest content of TGML (49.76%) was obtained at a molar ratio of triglycerol to lauric acid of 1.08, a reaction temperature of 84.93℃, a reaction time of 6 h and an enzyme dosage of 1.32%. After purification by molecular distillation combined with the washes with ethyl acetate and water, the purity of TGML reached 98.3%. Through characterization by electrospray-ionization mass spectrometry, infrared spectrum and nuclear magnetic resonance, the structure of TGML was identified as a linear triglycerol combined with lauroyl at the end. Finally, the inhibitory effects of TGML on the growths of A. parasiticus and A. flavus and the secretion of aflatoxin b1 were evaluated by measuring the colony diameter, the inhibition rate of mycelial growth and the content of mycotoxin in the media. The results indicated that TGML had a stronger inhibitory effects on colony growth and mycelial development of both toxic molds compared to sodium benzoate and potassium sorbate, and the secretions of toxins from A. parasiticus and A. flavus were completely suppressed when adding TGML at 10 and 5 mM, respectively. Based on the above results, TGML may be used as a substitute for traditional antifungal agents in the food industry.

• Korean journal of food and cookery science
• /
• v.22 no.3 s.93
• /
• pp.337-345
• /
• 2006

The properties of various grains used for the solid-state cultivation of basidiomycetes were examined. The hydration time with cold water was 10 hours for malt soybean. The required hydration time for Job's tears, barley and wheat was 4, 6 and 12 hours, respectively, but the final moisture content ranged from 30 to 48 %, which was much less than the optimum moisture content for mycelial growth. For the mass cultivation of mycelia, the hydrated grains with cold water were placed in plastic bottles. The mycelial growth ra in e bottled grains was high in the early stage with inoculation of homogenized mycelium. The mycelium activity was maintained by adding sterilized water in the middle of the cultivation period. Jupjang underwent sensory evaluation to examine the possibility of utilizing basidiomycetes in functional foods. The grains fermented with Ganoderma lucidum was the best for Jupjang. The combination of malt soybean and Job's tears was the best for Jupjang. The acceptability of Jupjang was improved during the period of aging time.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.9
• /
• pp.1568-1572
• /
• 2007

To develop a natural fungicide against Botrytis cinerea and Colletotrichum gloeosporioides, a total of 25 essential oils were tested for their fumigant activity against post-harvest pathogens. The vaporous phases of oils were treated to each fungus on potato dextrose agar medium in half-plate separated Petri plates at $10\;{\mu}g$ per plate. The essential oil of Illicium verum strongly inhibited the mycelial growth of both B. cinerea and C. gloeosporioides by over 90%. On the other hand, the essential oil of Schizonepeta tenuifolia showed inhibitory activity against mycelial growth of only B. cinerea by over 90%. Gas chromatography-mass spectrometry and bioassay indicated trans-anethole in I. verum and menthone in S. tenuifolia as a major antifungal constituent. The essential oils of I. verum and S. tenuifolia and their major constituents could be used to manage post-harvest diseases caused by B. cinerea and C. gloeosporioides.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.2
• /
• pp.280-285
• /
• 2006

Methanol extract of the rhizomes of turmeric, Curcuma longa L., effectively controlled the development of red pepper anthracnose caused by Colletotrichum coccodes. In addition three antifungal substances were identified from the methanol extract of C. longa rhizomes as curcumin, demethoxycurcumin, and bisdemethoxycurcumin using mass and $^{1}H-NMR$ spectral analyses. The curcuminoids in a range $0.4-100\;{\mu}g/ml$ effectively inhibited the mycelial growth of three red pepper anthracnose pathogens, C. coccodes, C. gloeosporioides, and C. acutatum. The three curcuminoids inhibited mycelial growth of C. coccodes and C. gloeosporioides to an extent similar to the synthetic fungicide dithianon did, but the synthetic agent was a little more effective against C. acutatum. The curcuminoids also effectively inhibited spore germination of C. coccodes, and bisdemethoxycurcumin was the most active. Among the three curcuminoids, only demethoxycurcumin was effective in a greenhouse test in suppressing red pepper anthracnose caused by C. coccodes.

• Journal of the Korean Wood Science and Technology
• /
• v.26 no.1
• /
• pp.19-28
• /
• 1998

For cultivation on sawdust-bed of oak-mushroom until present time, inoculation of spawn on sawdust bed has been performed by sawdust spawn. But, liquid spawn may have advantages for rapid mass production of spawn, and now, sawdust-cultivation by liquid spawn inoculation should be applied instead of sawdust spawn. Therefore, investigations were performed to evaluate the effect of sawdust-cultivation by liquid spawn inoculation. The results were as follows: 1. When 11 kinds of liquid media were applied, the oak-mushroom culture medium was the most excellent in growth. Most suitable temperature at PDA was $25^{\circ}C$, and $22.5\sim27.5^{\circ}C$ in range were optimal for liquid culture. In liquid culture, amount of mycelial growth increases rapidly up to 40 days of cultivation. Incubation at fermentor brought yield of 106mg dry mycelia per 40ml media after 17 days. 2. In 1l-spawn bottle, growth of mycelium by inoculation of 20ml-liquid spawns were faster than 6g-sawdust spawn in spread of mycelia. On 2kg-bag culture, inoculations of 10ml-, 20ml- and 30ml-liquid spawns were all slower than 20g-sawdust spawn in mycelial spread. So, amount increasement in ampunt of liquid spawn should be discussed. Yields of mushrooms until third sproutings of 2kg-bag culture were 580g in 30ml-liquid spawn inoculation, but 510g, 486g and 470g from 20g-sawdust spawn, 20ml-liquid spawn and 10ml-liquid spawn, respectively. Thus, 30ml-liquid spawn inoculation was highest in yield.

• Journal of Microbiology and Biotechnology
• /
• v.11 no.1
• /
• pp.56-60
• /
• 2001

A kerosene fungus of Cladosporium resinae NK-1 was examined for its ability to degrade individual n-alkanes and aromatic hydrocarbons by gas chromatography-mass spectrometry, and its organic solvent-tolerance was investigated by making use of the water-organic solvent suspension culture method. It grew on a wide range of solvents of varying hydrophobicities and it was found to have tolerance to various kinds of toxic organic solvents (10%, v/v) such as n-alkanes, cyclohexane, xylene, styrene, and toluene. A hydrocarbon degradation experiment indicated that NK-1 had a greater n-alkane degrading ability compared to that of the other selected strains. C. resinae NK-1, which could utilize 8-16 carbon chain-length n-alkanes of medium chain-length as a carbon source, could not assimilate the shorter chain-length n-alkanes and aromatic hydrocarbons tested so far. The n-alkane degrading enzyme activity was found in the mycelial extract of the organism.

• Microbiology and Biotechnology Letters
• /
• v.25 no.6
• /
• pp.586-591
• /
• 1997

In the course of screening for the tipA promoter-inducing substances, we isolated an active compound, sulfomycin Ia, from the mycelium of a microorganism designated 50634. The producing organism was identified as Streptomyces sp. on the basis of taxonomic studies. Sulfomycin Ia was purified from mycelial extract by silica gel column chromatography, LH-20 column chromatography, silica gel TLC, and preparative HPLC. The molecular weight of sulfomycin Ia was determined to be m/z 1129 (M+Na)$^{+}$ by FAB mass measurement and $^{1}$H NMR spectroscopic analysis. The structure was assigned as a derivative of sulfomycin I with thiazole, methyloxazole, oxazole, and pyridine rings by $^{1}$H NMR spectral data.

• Journal of Microbiology and Biotechnology
• /
• v.4 no.4
• /
• pp.354-359
• /
• 1994

An isolate, 90-GT-302, was found to produce antibiotics inducing typical mycelial swelling in Magnaporthe grisea and Fusarium solani. This isolate formed yellow substrate and white rectiflexbiles aerial mycelia in the early stages of growth. The aerial mycelium gradually changed its color to white and finally formed a gray spore mass. Analysis of the cell wall acid hydrolysate revealed the presence of LL- and meso-diaminopimelic acids, glycine, and galactose, which indicated cell wall type X. This result placed our isolate in genus Kitasatosporia. A comparison of isolate 9O-GT-302 with reference strains of Kitasatosporia spp., which not only demonstrated several differences in their physiological properties but also novelty of the active compounds produced by this isolate, led us to designate the isolate as Kitasatosporia kimorexae.