• Journal of Mushroom
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• v.15 no.4
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• pp.202-205
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• 2017

The potential risk of heavy metals and residual pesticides in imported sawdust media inoculated with oak mushroom cultures is a concern for safe mushroom production in Korea. To obtain preliminary data for a sound analysis of this risk, this study was undertaken to analyze the presence of heavy metals and residual pesticides in the oak mushroom media imported from six different regions in China, between 2013 and 2015. Lead, arsenic, chrome, mercury, and cadmium were analyzed; arsenic, chrome, and mercury were not detected. Lead was detected in the imported oak mushroom media from Jinlin, Shandong, Liaoning, and Tianjin. The detection level of lead ranged from 1.7 to 3.2 mg/kg. Cadmium was detected at a level of 0.028 to 0.037 mg/kg in the media from Shandong and Liaoning. No residual pesticides were detected in any of the samples.

• Journal of Mushroom
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• v.20 no.1
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• pp.22-28
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• 2022

In order to provide basic data for preparing management standards and to verify the safety of the Chinese oak mushroom-derived moisturizing medium-which is synthesized and imported in large quantities-the presence of 321 residual pesticides, 7 heavy metals, and 3 radioactive materials was analyzed in the moisturizer samples. Examination of residual pesticides in seven moisturizing medium samples prepared using the Chinese oak mushroom and three domestic sawdust samples used for mushroom culture revealed the presence of cypermethrin and iprodione in three moisturizer samples, but the contents of these pesticides were below the standard limits. Zn was detected in ten samples, Cu was detected in nine samples, and Ni was detected in four samples, but their contents were below the standard limits. Pb, Cd, Cr, and Hg were not detected in any sample. No radioactive materials were detected in the samples. In addition, fruiting bodies of the oak mushroom were observed in each medium. Examination did not reveal the presence of any residual pesticides or harmful compounds. In this study, the use of the moisturizing medium prepared using the Chinese oak mushroom was found to be safe. As residual pesticides, heavy metals, and radioactivity-even in trace amounts-remain concentrated in the human body, continuous verification of the safety of hazardous substances and pollutants during the systematic cultivation and management of these mushrooms is required.

• Journal of Applied Biological Chemistry
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• v.61 no.1
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• pp.69-73
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• 2018

Oak mushroom (Lentinus edodes) is cultivated by using oak logs and sawdust medium. Green mold (Trichoderma) infection on these media severely suppresses the growth of oak mushroom. Usages of antibiotics and chemicals are not generally allowed to control of green mold since the mushroom is a fresh food. Tolaasin and its analogues, peptide toxins secreted by Pseudomonas tolaasii, have the antifungal activity and they have been successful to control the green mold disease. When the green mold, Trichoderma harzianum H1, was cultured in the presence of these toxins, the growth of fungus was effectively suppressed. In sawdust media, when the bacterial culture supernatants were sprayed on the aerial hyphae of green molds, the fungal growth was completely suppressed. Particularly, the antifungal activity was greatly increased by the combined culture extracts of P. tolaasii 6264 and HK11 strains. Therefore, these bacterial strains and their peptide toxins were able to suppress the growth of green molds and these can be good candidates to prevent from Trichoderma disease in oak mushroom cultivation.

• Journal of Mushroom
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• v.21 no.3
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• pp.160-166
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• 2023

The effects of punching treatment on mycelial culture and fruiting body productivity were investigated in a new Lentinula edodes cultivar, "Jadam", in sawdust medium for the stable production of oak mushroom. As the punching volume and number increased, the weight loss rate and color difference increased and the L value decreased. After spawn inoculation, the sawdust medium temperature and CO₂ concentration reached their highest values at 33 and 19 days of incubation, respectively. The O₂ concentration showed the lowest value on the 14^th day of incubation, which was the opposite pattern to the CO₂ concentration. As the punching volume and the number increased, the medium temperature and O₂ concentration increased, and the CO₂ concentration decreased. Higher punching volumes and numbers resulted in higher temperatures and lower CO₂ concentrations. The best fruiting body yield was 5 × 70 mm - 30 (punching diameter × depth - number), and the total yield after three cycles was 644.7 g.

• The Korean Journal of Mycology
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• v.47 no.4
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• pp.385-392
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• 2019

Currently, plastic bags are being used for sawdust cultivation of shiitake mushroom. However, due to serious environmental problems caused by the use of plastic bags, we studied the efficacy of bottle cultivation method to replace the sawdust bag method. Small detachable plastic bottles (400 g capacity) filled with Quercus spp. sawdust and wheat bran (4:1 w/w) media were incubated for 80 and 120 days. The weight loss (%) of the media was higher for the NIFoS 2464 strain at an approximate light intensity of 300 Lux than light intensity of 500 Lux; the light intensity was associated with the loss of sawdust medium-weight during the cultivation period. The highest yield was observed when the strain was cultivated for 80 days under dark conditions, 40 days under 500 Lux light, and air circulation fan speed of 30 rpm. When incubated for 120 days, mushroom yield in the bottle media was higher at 40 days of light exposure than 20 days of light exposure. In the bottle media incubated for 80 days under dark conditions, the mushrooms fruited due to repetitive water spraying on the top of the media and light stimulation during the fruiting period. The media could be separated from the bottles because the media shrank after the first harvest. These separated plastic bottles could be re-used for mushroom cultivation, thereby reducing the amount of plastic waste.

• Journal of Mushroom
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• v.10 no.4
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• pp.179-183
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• 2012

This study was conducted to determine proper amount of media and the effect of fermented sawdust on yield of Grifola frondosa in bag culture. The yield of Grifola frondosa was 227 g for 2 kg of media compared with 103 g for 1kg, 256 g for 2.5 kg, and 312 g for 3 kg. The greatest yield of Grifola frondosa per mass of media was 114 g/kg media for 2 kg of media. Days to harvest for 2 kg of media was 95 days compared with 93 days for 1kg, 99 days for 2.5kg, and 104 days for 3kg. Addition of fermented oak sawdust increased yield from 90 to 145 g/kg bag for Hambak cultivar and from 104 to 121 g/kg bag for Yipsae1ho cultivar. Culture duration was shorten 4-7 days by treating fermented oak sawdust.

• Journal of Mushroom
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• v.7 no.1
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• pp.22-26
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• 2009

These experiments were conducted to find the optimum mixing rate of used media for saving the production cost of Flammulina velutipes. The materials for media formation was used needle-leaf tree sawdust, media that finished 1th cultivation of F. velutipes, corncob meal, and rice bran, wheat bran as nutrition source. We inoculated the F. velutipes in 14 kinds of different media types and checked the spawn growth speed, fruit body quality and quantity. Two nutrition agents, which is rice bran and wheat bran, did not affected the incubation period, but the effective stem number, quality and quantity of fruit body was better at rice bran than wheat bran. The quality of fruit body produced at mixed 20% of used media (needle-leaf tree sawdust 60% + used media 20% + rice bran 20%) was similar to control plot (needle-leaf tree sawdust 80% + rice bran 20%), but the yield was improved 10% than control plot 130g. According as the used-media mixing amount increases, quality and quantity of fruit body became low remarkably. Therefore, the optimum mixing amount of used-media was 20% and it increased 10% of fruitbody yield.

• Journal of Mushroom
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• v.6 no.1
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• pp.38-41
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• 2008

Studies were processed to confirm the difference of the shiitake productivity according to different spawn shapes(sawdust, plug-shaped and liquid spawns) on middle-temperature type strain. A tendency of fruiting was similar among three treatments, and treatments inoculated with plug-shaped spawn and liquid spawn produced over 50 % of total yield until 2nd flushing period and 80 % of total yield until 4th flushing period. In investigation of deformed fruit-bodies, all of three treatments occurred until 2nd flushing period. However, in rate of deformed fruit-bodies, treatment inoculated with liquid spawn was lower than others. In investigation of yield, the amount produced on treatment inoculated with liquid spawn was 411 g per medium and it was highest among treatments. And the amount of fruit-bodies over 10 g was higher than others. Also, the number of fruit-bodies between sawdust and plug-shaped spawn was different, but each weight of fruit-bodies among three treatments was not different.

• Journal of Mushroom
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• v.19 no.1
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• pp.1-8
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• 2021

The choice of the culture medium is an important factor for the mass production of mycelia in submerged cultures. The influence of liquid medium on the mycelial dry weight of Paecilomyces tenuipes was investigated in this study. The regression equation is expressed as Y=-1292.94187+17.78612X1+18.92425X2+2.11464X3-0.019375X1X2-0.006276X1X3+0.008177X2X3-0.070169X12-0.292175X22-0.008818X32, where Y represents the value of the mycelial dry weight (g/L), X1 is the particle size of wood sawdust in liquid medium (mesh), X2 is the concentration of the wood sawdust in liquid medium, and X3 is incubation time (h). The medium was optimized using a response surface methodology, and the optimal medium contained 30 g of wood sawdust (140 mesh), 20 g of glucose, and 10 g/L of peptone. Under these conditions, the mycelial dry weight reached 38.1 g/L (actual value). The culture medium containing wood sawdust is simple and easy to use, highly efficient, and eco-friendly, and its effectiveness in large preparations of P. tenuipes mycelia with low material costs has been demonstrated.

• Mycobiology
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• v.43 no.3
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• pp.327-332
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• 2015

Phenylalanine ammonia-lyase (PAL) gene is known to be expressed in plants, and is involved in the differentiation, growth and synthesis of secondary metabolites. However, its expression in fungi remains to be explored. To understand its expression in mushroom fungi, the PAL gene of the edible mushroom Flammulina velutipes (Fvpal) was cloned and characterized. The cloned Fvpal consists of 2,175 bp, coding for a polypeptide containing 724 amino acids and having 11 introns. The translated amino acid sequence of Fvpal shares a high identity (66%) with that of ectomycorrhizal fungus Tricholoma matsutake. Distinctively, the Fvpal expression in the mycelium was higher in minimal medium supplemented with L-tyrosine than with other aromatic amino acids. During cultivation of the mushroom on sawdust medium, Fvpal expression in the fruit body correspondingly increased as the mushroom grew. In the fruiting body, Fvpal was expressed more in the stipe than in the pileus. These results suggest that F. velutipes PAL activity differs in the different organs of the mushroom. Overall, this is first report to show that the PAL gene expression is associated with mushroom growth in fungi.