Oyster mushroom is one of the most widely cultivated and consumed mushrooms in Korea, and mechanization and automation of cultivation systems have enabled mass production. Many cultivars have been developed to replace the old ones such as ‘Suhan‘ and ‘Chunchuneutari 2 ho,‘ which have been cultivated for over 20 years. Among these, ‘Soltari‘ was developed in 2015. Although it has excellent quality, its cultivation is challenging and the productivity is somewhat lower. To address these issues, the Mushroom Division at the National Institute of Horticultural and Herbal Science selected the genetic resource KMCC05165 and attempted hybridization between monokaryons from KMCC05165 and ‘Soltari(KMCC04940)’. Through repeated cultivation tests and evaluation of fruiting body characteristics, the superior strain ‘Po-2019-smj22’ was selected and finally named ‘Otari‘. The optimal mycelial growth temperature of ‘Otari’ was between 25 and 30°C and optimal fruiting body growth temperature was between 13 and 18°C. Mycelial growth on PDA medium was best at 25°C, and at the same temperature, mycelial growth was similar across four media: PDA, MEA, MCM, and YM. In 1,100 mL bottle cultivation, the yield was approximately 174 g, which is about 5% higher than the control cultivar ‘Soltari‘, and the number of valid individuals was also higher at about 25. The diameter and height of the pileus were 29.8 mm and 17.6 mm, respectively, slightly smaller than ‘Soltari‘, and the stipe was thin and long with a thickness of 12.2 mm. Additionally, the pileus’ lightness index (L index) was 30.7, indicating a darker brown color compared to 'Soltari.' With excellent mycelial growth, ease of cultivation, and high yield, the new cultivar ‘Otari‘ is expected to be widely adopted by domestic oyster mushroom farms.

The oyster mushrooms have known to be a major product in Gyeonggi-do, with production accounting for 69% of the entire country. The ‘Daeseon’ cultivar, which has white and straight stem, was developed. This cultivar was developed by mating monokaryons isolated from the ‘Heuktari’ and ‘Hwaseong-2ho’ varieties. The optimum temperature for the mycelial growth was 26~32oC on PDA medium and that for the primordia formation and the growth of fruit body of ‘Daeseon’ was 16~20oC on sawdust media. It took 35 days to complete spawn running, 3 days for finish primordia formation, and 4 days for finish fruit body growth in the bottle culture. It has shallow funnel-shaped pileus and a white straight stipe. The yield per bottle was 201 g/1,100 ml and was 16% higher than that of control cultivar ‘Suhan-1ho’. Based on above results, we expect this cultivar to be suitable for small packaging.

We developed a new oyster mushroom cultivar named 'Dawon-tari', which has a longer stipe and higher yield than those of ‘sootari’.‘Dawon-tari’ was crossed by mating monokaryons isolated from ‘Sootari’ and ‘Daejang2ho’. The optimal temperature for mycelial growth was determined to be 20~25°C on potato dextrose agar medium, while the optimal temperatures for primordia formation and fruiting body growth were 15~17°C on a sawdust substrate. During bottle cultivation, the mycelial growth phase required approximately 26 days. Additionally, primordia formation required 5 days, and fruiting body growth took 4 days. The fruiting bodies exhibited a shallow funnel shape; were grayishbrown; and the stipes were characterized by a long, thin structure. The yield of fruiting bodies was 185 g per 1,100 mL bottle, which was 5% higher than that of ‘Sootari’.

In this study, we investigated the microbial community of oyster mushrooms at different growth stages at the species level. Gram-positive bacteria were predominant in the presterilized medium. On the other hand, Gram-negative bacteria were predominant in the culture-completed medium, post-harvest medium, and fruiting bodies. In addition, Pseudomonas tolaasii, which is known to cause disease in mushrooms, was confirmed in the cultured medium, post-harvest medium, and fruiting bodies, and it was determined that the mycelium culture stage was contaminated, and the reason why no disease occurred was Sphingobacterium psychroaquaticum. It was confirmed that this was because the growth of Pseudomonas tolaasii was suppressed by producing a component called tolacin. As a result of confirming the diversity of microorganisms, it was confirmed that the presterilization medium contains a variety of microorganisms compared to other growth stages, and the diversity decreases in the order of culture completion medium, fruiting body, and post-harvest medium. showed a trend. As a result of microbial similarity analysis, it was confirmed that the cultured medium and the post-harvest medium showed similar microbial communities, and in the case of fruiting bodies, there were some similarities but overall differences.

This study analyzed the effects of different nitrogen sources in substrate composition on the growth of Pleurotus ostreatus, as well as the subsequent changes in flavor and antioxidant activity. The T2, composed of poplar sawdust, beet pulp, cotton seed dregs, and cotton seed coat in a ratio of 40:20:20:20, exhibited the highest yield at 156.6 g. The total polyphenol content and ABTS and DPPH radical scavenging activities were 8.25 mg GAE/g, 70%, and 49%, respectively, showing higher radical scavenging activity compared to the Control and T1. Additionally, varying nitrogen content resulted in distinct aroma patterns and is presumed to influence taste profiles such as sourness, umami, and saltiness.

In this study, Pleurotus ostreatus No.42 was cultured in glucose-peptone-yeast-wheat bran medium using a previously reported novel rotary draft tube bioreactor. Versatile peroxidase (VP), a lignin-degrading enzyme, was isolated from a pellet-type mycelium culture grown in the medium for seven days. The VP was purified by sequentially applying ultra-filtration, DEAESepharose CL-6B column, and Mono Q column. SDS-PAGE analysis revealed the molecular weight of VP to be 36.4 KDa with an isoelectric point of 3.65. The amino acid sequence was confirmed as VTCATGQTT. The purified VP was observed to possess the property of not only oxidizing Mn ions but also decomposing veratryl alcohol, a non-phenolic compound. The catalytic ability of VP is a subject for future research.

The development of automated bottle cultivation systems has facilitated the large-scale production of Pleurotus ostreatus, a commonly cultivated oyster mushroom species in South Korea. However, as the consumption of this product is decreasing and production quantities are exceeding demand, farmers are seeking various other mushroom types and cultivars. In response to this, we have developed a new oyster mushroom cultivar named 'Sena'. This high-yielding cultivar has a white pileus and excellent quality. The white oyster mushroom cultivars 'Goni' and 'Miso' were selected as parental strains from the genetic resources of the National Institute of Horticultural and Herbal Science’s Mushroom Division. By crossing their monokaryons, hybrids were developed and subjected to cultivation trials and characteristic evaluations to select the superior cultivar. The optimal temperature for 'Sena' mycelial growth is 25–30°C, with inhibition occurring at temperatures above 30°C, whereas the temperature for mushroom growth is 14–18°C. The mushrooms grow in clusters, with the white pileus having a shallow funnel shape. Optimal mycelial growth occurs in malt extract agar medium. When cultivated in 1,100 cc bottles, the 'Sena' cultivar had 35 available individuals, surpassing the number 16 available from the control cultivar 'Goni'. The yield per bottle also increased by approximately 157 g, a 24% increase over the control cultivar amount. When 300 g samples of harvested mushrooms were packed and stored at 4°C in a cold storage facility for 28 days, the weight loss rate of ‘Sena’ was approximately 4.22%, lower than that of 'Goni'. Moreover, the changes in pileus and stipe whiteness (measuring 6.99 and 8.33, respectively) were also lower than those of the control cultivar. Since the appearance of a white cap is crucial for quality assessment, the 'Sena' cultivar is superior to the 'Goni' cultivar in terms of both weight and quality after undergoing lowtemperature storage.

We conducted an on-site application study at the livestock cooperative fertilizer plant to compare the composting period, temperature change, moisture content, and chemical properties between livestock manure compost using sawdust as a moisture regulator with those using spent oyster mushroom substrate. The composting period, moisture content, and fertilizer composition of compost containing spent oyster mushroom substrate did not differ from that of conventional compost mixed with sawdust after the first and second fermentation and post-maturation stages, it was suitable as a material for manufacturing livestock manure compost. The spent oyster mushroom substrate also lower the production cost of livestock manure compost by replacing the more expensive sawdust. The developed technology is expected to contribute towards the utilization of by-products of the oyster mushroom harvest while simultaneously producing high quality livestock manure compost.

The oyster mushroom is a widely cultivated edible mushroom in Korea. It is a regionally specialized crop in Gyeonggi-do, where 68% of the national production is produced. The present study was conducted to develop a new, highquality cultivar with stable cultivation. ‘Manseon’ is a new variety of oyster mushroom suitable for bottle culture. It was produced by mating monokaryons isolated from ‘HB-18’ and ‘P15159-16’. The optimal temperature for ‘Manseon’ mycelial growth was 26–29 °C on potato dextrose agar (PDA) medium and for primordia formation and the growth of fruit bodies the optimal temperature was 18–19 °C on sawdust medium. Spawn running required 30 d, primordia formation required 4 d, and fruit body growth in the bottle culture required 4 d. Regarding the characteristics of the fruit bodies, the pilei were round and dark grayish brown, stipe color was white, and stipe shape was short and thick. The yield per bottle was 192.7 g/1,100 cc, which was 9% higher than that of the control strain (Suhan-1ho). The physical properties of springiness, cohesiveness, gumminess, and brittleness of stipe tissue were 87.9%, 77.4%, 445.1 kgf, and 389.6 kgf, respectively.

In this study, we aimed to compare the mycelial growth of Pleurotus ostreatus after medium supplementation with various amino acids at different concentrations to select the optimal medium nutrient composition for mycelial growth. The mycelial growth of P. ostreatus was investigated after adding four amino acids (tryptophan, threonine, methionine, and lysine) at 0.5% or 1% to the medium.The rate of P. ostreatus mycelial growthwas faster in the potato dextrose agar (PDA) medium supplemented with threonine at 0.5% or 1% than that of the control, whereas it was inhibited by tryptophan treatment. Supplementation of sawdust mediumwith all amino acids, except tryptophan, at 0.5% did not alter the mycelial growth, compared to the controls. However, addition of any amino acid to sawdust medium at a higher concentration (1%) inhibited the mycelial growth. The laccase acitivity of P. ostreatus mycelium cultured in PDA medium was the highest when threonine was added, and the lowest when tryptophane was added, consistent with the results of the mycelial growth. Therefore, the addition of threonine, methionine, or lysine to PDA medium at a concentration of 0.5-1%was effective for increasing the mycelial growth of P. ostreatus; however, it inhibited mycelial growth insawdust medium, suggesting that the effects of amino acids dependedon the medium nutrient composition.