• Journal of Mushroom
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• v.14 no.4
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• pp.162-167
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• 2016

Lactic acid bacteria (LAB) producing phenyllactic acid (PLA), which is known as antimicrobial compound, was isolated from button mushroom bed and the isolated LAB was identified to Lactobacillus casei by 16 rRNA gene sequence analysis. Cell-free supernatant (CFS) from L. casei was assessed for both the capability to produce the antimicrobial compound PLA and the antifungal activity against three fungal pathogens (Rhizoctonia solani, Botrytis cinerea, and Collectotricum aculatum). PLA concentration was investigated to be 3.23 mM in CFS when L. casei was grown in MRS broth containing 5 mM phenylpyruvic acid as precursor for 16 h. Antifungal activity demonstrated that all fungal pathogens were sensitive to 5% CFS (v/v) of L. casei with average growth inhibitions ranging from 34.58% to 65.15% (p < 0.005), in which R. solani was the most sensitive to 65.15% and followed by C. aculatum, and B. cinerea. The minimum inhibitory concentration (MIC) for commercial PLA was also investigated to show the same trend in the range of 0.35 mg mL-1 (2.11 mM) to 0.7 mg mL-1 (4.21 mM) at pH 4.0. The inhibition ability of CFS against the pathogens were not affected by the heating or protease treatment. However, pH modification in CFS to 6.5 resulted in an extreme reduction in their antifungal activity. These results may indicate that antifungal activities in CFS was caused by acidic compounds like PLA or organic acids rather than protein or peptide molecules.

• Mycobiology
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• v.36 no.1
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• pp.13-18
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• 2008

Eight distinct bacteria were isolated form diseased mycelia of the edible mushroom, Pleurotus eryngii. 16S rDNA sequence analysis showed that the isolates belonged to a variety of bacterial genera including Bacillus (LBS5), Enterobacter (LBS1), Sphingomonas (LBS8 and LBS10), Staphylococcus (LBS3, LBS4 and LBS9) and Moraxella (LBS6). Among them, 4 bacterial isolates including LBS1, LBS4, LBS5, and LBS9 evidenced growth inhibitory activity on the mushroom mycelia. The inhibitory activity on the growth of the mushroom fruiting bodies was evaluated by the treatment of the bacterial culture broth or the heat-treated cell-free supernatant of the broth. The treatment of the culture broths or the cell-free supernatants of LBS4 or LBS9 completely inhibited the formation of the fruiting body, thereby suggesting that the inhibitory agent is a heat-stable compound. In the case of LBS5, only the bacterial cell-containing culture broth was capable of inhibiting the formation of the fruiting body, whereas the cell-free supernatant did not, which suggests that an inhibitory agent generated by LBS5 is a protein or a heat-labile chemical compound, potentially a fungal cell wall-degrading enzyme. The culture broth of LBS1 was not inhibitory. However, its cell-free supernatant was capable of inhibiting the formation of fruiting bodies. This indicates that LBS1 may produce an inhibitory heat-stable chemical compound which is readily degraded by its own secreted enzyme.

• Journal of Mushroom
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• v.9 no.3
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• pp.101-104
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• 2011

We aimed to develop a new variety of Neolentinus lepideus from about forty strains by bag culture. To this end, "Solhyang" which means pine smell in Korean was selected as a new commercial variety of N. lepideus. N. lepideus have yellow pileus and pine smell, which characteristics make a favorable impression on the far east Asia, Korean and Japanese. The optimum temperatures for mycelial growth and fruit body development ranged $26{\sim}32^{\circ}C$ and $18{\sim}20^{\circ}C$, respectively. The required periods of mycelial incubation and fruit body growth were 30 days and 7 days, respectively. The fresh weight of fruit body was 115g/kg with pine sawdust and corn meal power(9:1, v/v) substrate.

• Journal of Mushroom
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• v.19 no.4
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• pp.272-278
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• 2021

Bacillus velezensis HKB-1 was isolated from the composted spent mushroom substrate of Lentinula edodes (LeCSMS) and inhibited mycelial growth of phytopathogenic fungal species, Phythhopthora capsici, Collectotrichum coccodes and Fusarium oxysporium by more than 70%. B. velezensis HKB-1 showed bacterial growth rate 10 to 100 times higher than that of other commercial bacterial media in water extract of LeCSMS supplemented with 1% molasses. The LeCSMS medium was effective in promoting the growth of pepper and controlling Phytophthora blight disease of pepper.

• Journal of Mushroom
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• v.14 no.4
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• pp.142-154
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• 2016

Worldwide production of mushrooms has been increasing by 10-20% every year. Recently, Pleurotus eryngii and P. nebrodensis have become popular mushroom species for cultivation. In particular, China exceeded 8.7 million tons in 2002, which accounted for 71.5% of total world output. A similar trend was also observed in Korea. Two kinds of mushrooms-Gumji (金芝; Ganoderma) and Seoji-are described in the ancient book 'Samguksagi' (History of the three kingdoms; B.C 57~A.D 668; written by Bu Sik Kim in 1145) during the Korea-dynasty. Many kinds of mushrooms are also described in more than 17 ancient books during the Chosun-dynasty (1392~1910) in Korea. Approximately 200 commercial strains of 38 species of mushrooms were developed and distributed to cultivators. The somatic hybrid variety of oyster mushroom, 'Wonhyeong-neutari,' was developed by protoplast fusion, and distributed to growers in 1989. Further, the production of mushrooms as food was 199,829 metric tons, valued at 850 billion Korean Won (one trillion won if mushroom factory products are included) in 2015. In Korea, the major cultivated species are P. ostreatus, P. eryngii, Flammulina velutipes, Lentinula edodes, Agaricus bisporus, and Ganoderma lucidum, which account for 90% of the total production. Since mushroom export was initiated in 1960, the export and import of mushrooms have increased in Korea. Technology was developed for liquid spawn production, and automatic cultivation systems led to the reduction of production cost, resulting in the increase in mushroom export. However, some species were imported owing to high production costs for effective cultivation methods. In academia, RDA scientists have conducted mushroom genome projects since 1997. One of the main outcomes is the whole genome sequencing of Flammulina velutipes for molecular breeding. With regard to medicinal mushrooms, we have been conducting genome research on Cordyceps and its related species for developing functional foods. There are various kinds of beneficial substances in mushrooms; mushroom products, including pharmaceuticals, tonics, healthy beverages, functional biotransformants, and processed foods have also became available on the market. In addition, compost and feed can likewise be made from mushroom substrates after harvest.

• Mycobiology
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• v.42 no.3
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• pp.296-300
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• 2014

We selected Pleurotus ostreatus from among several edible mushrooms because it has high anti-gout xanthine oxidase (XOD) inhibitory activity. The maximal amount of XOD inhibitor was extracted when the Pleurotus ostreatus fruiting body was treated with distilled water at $40^{\circ}C$ for 48 hr. The XOD inhibitor thus obtained was purified by Sephadex G-50 gel permeation chromatography, ultrafiltration, $C_{18}$ solid phase extraction chromatography and reverse-phase high-performance liquid chromatography with 3% of solid yield, and its XOD inhibitory activity was 0.9 mg/mL of $IC_{50}$. The purified XOD inhibitor was a tripeptide with the amino acid sequence phenylalanine-cysteine-histidine and a molecular weight of 441.3 Da. The XOD inhibitor-containing ultrafiltrates from Pleurotus ostreatus demonstrated dose-dependent anti-gout effects in a Sprague-Dawley rat model of potassium oxonate-induced gout, as shown by decreased serum urated levels at doses of 500 and 1,000 mg/kg, although the effect was not as great as that achieved with the commercial anti-gout agent, allopurinol when administered at a dose of 50 mg/kg.

• Mycobiology
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• v.42 no.2
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• pp.193-197
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• 2014

Laccase activity of Pleurotus ostreatus is significantly increased by the addition of apple pomace. Among various conditions, the best concentration of apple pomace and cultivation time for the production of laccase by P. ostreatus was 2.5% and 9 days, respectively. Reverse transcription polymerase chain reaction analyses of laccase isoenzyme genes, including pox1, pox3, pox4, poxc, poxa3, and poxa1b, revealed a clear effect of apple pomace on transcription induction. Our findings reveal that the use of apple pomace can be a model for the valuable addition of similar wastes and for the development of a solid-state fermenter and commercial production of oyster mushroom P. ostreatus.

• Mycobiology
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• v.39 no.2
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• pp.85-91
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• 2011

We investigated the effect of nutritional and environmental factors on Ophiocordyceps longissima mycelial growth. The longest colony diameter was observed on Schizophyllum (mushroom) genetics complete medium plus yeast extract, Schizophyllum (mushroom) genetics minimal medium, and Sabouraud dextrose agar (SDA); however, malt-extract yeast-extract agar, SDA plus yeast extract, yeast-extract malt-extract peptone dextrose agar, SDA, oatmeal agar, and potato dextrose agar showed higher mycelia density. A temperature of $25^{\circ}C$ was optimum and 7.0 was the optimum pH for mycelial growth. Colony diameter was similar under light and dark conditions. Maltose and yeast extract showed the highest mycelial growth among carbon and nitrogen sources respectively. The effect of mineral salts was less obvious; however, $K_3PO_4$ showed slightly better growth than that of the other mineral salts tested. Among all nutrition sources tested, complex organic nitrogen sources such as yeast extract, peptone, and tryptone were best for mycelial growth of O. longissima. Ophiocordyceps longissima composite medium, formulated by adding maltose (2% w/v), yeast extract (1% w/v), and $K_3PO_4$ (0.05% w/v) resulted in slightly longer colony diameter. In vitro mycelial O. longissima growth was sustainable and the production of fruiting bodies could be used for commercial purposes in the future.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.20 no.3
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• pp.71-76
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• 2014

Master packaging system is a technology combining primary and secondary packaging to preserve the fresh produce in the supply chain. Master packaging system with tailor-designed gas transfer and $CO_2$ absorber of $Ca(OH)_2$ was applied to fresh shiitake mushroom in its supply from farm to retail store. The temperature, humidity and package atmosphere were monitored through the distribution and/or storage until the packages were opened to measure the mushroom quality. Conventional perforated individual packages without secondary master pack were prepared and travelled the same path for comparison purpose. While high temperature history was observed in some initial period of actual practice of the mushroom transportation and storage unexpectedly, the package atmosphere around the produce in the master packaging system was maintained at modified atmosphere consisting of $O_2$ concentration of 0.4 to 4.2% and $CO_2$ concentration of 0.7 to 1.7%, which is known to be beneficial for the mushroom preservation. While curing the mushrooms with precooled drying was effective for quality preservation, positive effect of master packaging system could be apparent for the uncured mushroom. Harmonized combination of curing treatment, master packaging system and temperature management was suggested for the best quality preservation of the fresh shiitake mushroom.

• Journal of Mushroom
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• v.13 no.3
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• pp.223-227
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• 2015

The study was conducted to investigate the effects of post-incubation period and temperature treatment conditions during incubation on the uniform primordia formation and cultural characteristics of oyster mushroom (Pleurotus ostreatus). Three kinds post-incubation period; 25, 30, 35 days and control were applied for 30 days while two kinds incubation room temperature $23^{\circ}C$ and $26^{\circ}C$ and control were used $20^{\circ}C$. The substrate temperature during pre-incubation was of 'Suhan No. 1' and 'Gonji No. 7'. Oyster mushroom varieties tended to increase between $24^{\circ}C$ to $26^{\circ}C$ at 11 to 15 days after inoculation and then they were maintained in treatment temperature during post -incubation period. The $CO_2$ occurrence was at the highest at 6,500 ppm for 'Suhan No. 1' and 5,800 ppm for 'Gonji No. 7' at the time of the highest temperature increase. The ratio of un-uniformal primordia formation and the ratio of non-commercial fruit body were reduced by 40%, 10.5%, respectively compared to control for 'Suhan No. 1' when in the post-incubation temperature was $26^{\circ}C$, and incubated for 10 days and 15 days treatment. Also, 'Gonji No. 7' was reduced by 19%, 9.5%, respectively when in the post-incubation temperature was $26^{\circ}C$, and incubated for 10 days treatment. Therefore, the higher post-incubation temperature of room and longer post-incubation period resulted in the higher percentage of primordia formation of two cultivars.