• Journal of Microbiology and Biotechnology
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• v.23 no.11
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• pp.1577-1585
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• 2013

Bioethanol production from lignocellulose is considered as a sustainable biofuel supply. However, the low cellulose hydrolysis efficiency limits the cellulosic ethanol production. The cellulase is strongly inhibited by the major end product cellobiose, which can be relieved by the addition of ${\beta}$-glucosidase. In this study, three ${\beta}$-glucosidases from different organisms were respectively expressed in Saccharomyces cerevisiae and the ${\beta}$-glucosidase from Saccharomycopsis fibuligera showed the best activity (5.2 U/ml). The recombinant strain with S. fibuligera ${\beta}$-glucosidase could metabolize cellobiose with a specific growth rate similar to the control strain in glucose. This recombinant strain showed higher hydrolysis efficiency in the cellulose simultaneous saccharification and fermentation, when using the Trichoderma reesei cellulase, which is short of the ${\beta}$-glucosidase activity. The final ethanol concentration was 110% (using Avicel) and 89% (using acid-pretreated corncob) higher than the control strain. These results demonstrated the effect of ${\beta}$-glucosidase secretion in the recombinant S. cerevisiae for enhancing cellulosic ethanol conversion.

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.171-177
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• 2004

The endoxylanase (642 bp; 213 amino acids) and $\beta$-xylosidase (1,602 bp; 533 amino acids) genes from Bacillus sp. were amplified by PCR and separately inserted into the downstream of the yeast ADH1 promoters, resulting in the pAEDX-1 (7.63 kb) and pAEX (8.47 kb) plasmids, respectively. When the yeast transformants, S. cerevisiae SEY2102 harboring pAEDX-1 or pAEX, were grown on YPD medium, the total activities of the enzymes were approximately 9.8 unit/ml for endoxylanase and 2.9 unit/m1 for $\beta$-xylosidase. When the three kinds of xylan from oat spelts, birch wood, and corncob were hydrolyzed by treating with recombinant endoxylanase and $\beta$-xylosidase, it was found that xylose, xylobiose, and xylotriose were produced. To efficiently hydrolyze xylan, various reaction conditions such as amount of enzymes, substrate type, substrate concentration, temperature, and reaction time were examined. The optimized conditions for the hydrolysis of xylan were as follows: amount of endoxylanase, 10 units; amount of $\beta$-xylosidase, 10 units; temperature, $50^\circ{C}$; substrate type, oat spelts xylan; substrate concentration, 6%; reaction time, 1 h. Under the optimal condition, xylose was mainly produced from oat spelts xylan by cooperative action of endoxylanase and $\beta$-xylosidase.

• The Korean Journal of Mycology
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• v.24 no.2 s.77
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• pp.127-134
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• 1996

Armillaria isolates (KNU-A110, KNU-A234, KNU-A1022 and KNU-A1030) were excellent isolates for producing Gastrodia tuber in farm cultivation. Depth of soil between $10\;cm{\sim}19\;cm$ was favorable for producing Gastrodia tuber and rhizomorph at cultivated area. Eighty nine isolates were collected from 5 countries; 16 from Japan, 22 from USA, 26 from France, 4 from Africa and 21 from Korea. Mycelial fan of most isolates were better formed on basal medium with lemon extract than without lemon.A. mellea (KNU-A997) were strongly pathogenic to Gastrodia but A. gallica (KNU-A110) were excellent symbiotic to Gastrodia tuber. Mycelial growth were good on basal medium containing $0.25%{\sim}0.5%$ ethanol and sawdust spawn added wheat bran and corncob. Liquid culture inoculation were not only fast growth of mycelium but also reduction of contamination.

• The Korean Journal of Mycology
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• v.39 no.3
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• pp.171-174
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• 2011

This study was carried out to elucidate suitable supplementary nutrition for Neolentinus lepideus cultivation. The main substrate for cultivation was douglas fir sawdust, and supplementary materials for experiment were corn meal, corn hull, corncob, beet pulp, and potato starch. The higher amount of total nitrogen source was showed in corn meal (0.45%) than any other nutritive materials. Incubation ratio and cultivation period showed the best 97% and the shortest 43 days on medium with corn meal substrate. The fruit body yield and biological efficiency on medium with 10% corn meal were highest 122 g/1 kg and 35%, respectively. Factor analyses concerning fruiting yield showed total nitrogen source (r = 0.95) and crude fat (r = 0.65). These results are recommended that N. lepideus cultivation is corn meal material as the source of the supplementary nutrition and total nitrogen source as the factor of fruiting body yield on the Douglas fir sawdust medium.

• Mycobiology
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• v.43 no.4
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• pp.423-434
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• 2015

The study was conducted to compare the effects of different agro-wastes on the growth, yield, and nutritional composition of oyster mushrooms Pleurotus ostreatus (PO) and Pleurotus cystidiosus (PC). Seven substrate formulas including sawdust (SD), corncob (CC), sugarcane bagasse (SB) alone and in combination of 80 : 20, 50 : 50 ratio between SD and CC, SD and SB were investigated. The results indicated that different substrate formulas gave a significant difference in total colonization period, characteristics of fruiting bodies, yield, biological efficiency (BE), nutritional composition and mineral contents of two oyster mushrooms PO and PC. The results showed that increasing CC and SB reduced C/N ratio, and enhanced some mineral contents (Ca, P, and Mg) of substrate formulas. The increased amount of CC and SB of substrate formulas enhanced protein, ash, mineral contents (Ca, K, Mg, Mn, and Zn) of fruiting bodies of both mushrooms. Substrates with 100% CC and 100% SB were the most suitable substrate formulas for cultivation of oyster mushrooms PO and PC in which they gave the highest values of cap diameter, stipe thickness, mushroom weight, yield, BE, protein, fiber, ash, mineral content (Ca, K, and Mg) and short stipe length. However, substrate formula 100% CC gave the slowest time for the first harvest of both mushrooms PO and PC (46.02 days and 64.24 days, respectively). It is also found that the C/N ratio of substrate formulas has close correlation with total colonization period, mushroom weight, yield, BE and protein content of mushroom PO and PC.

• Journal of Mushroom
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• v.11 no.4
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• pp.208-213
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• 2013

The contents of raw materials which are components of mixed substrate for mushroom cultivation were analyzed to optimize the composition. The pure protein(amino acid) level of soybean meal was the highest, 44.02% followed by those of soybean curd residue(31.5%) and cotton seeds meal(30.6%). The non protein nitrogen(NPN) contents in crude protein of main nitrogen materials were 2.4% for soybean meal and 5.6% for dried soybean curd residue, while those of wheat bran and rice bran used as the carbon source were relatively higher, 17.6% compared to that of nitrogen supplying media. Crude protein content per price was 6.0 for rapeseed meal, indicating that it is high crude protein content per price. Nitrogen-free extract(NFE) considering as an ingredient for mycelial growth were high in alphacorn(72.9%) and wheat bran B(57.2%). Acid detergent fiber(ADF) was high in corncob, 51.88%, its use for cultivation of brown rot fungi including Lentinus lepideus should pay attention because the fungi lack complete lignin degradation activity.

• The Korean Journal of Mycology
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• v.48 no.4
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• pp.407-414
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• 2020

To replace the sawdust in the growth medium of oyster mushroom to utilize its by-product spent mushroom substrates (SMS) as feed for ruminant, we performed cultivation test using cotton seed hull pellet (CSHP), corn stalk pellet (CSP), corncob (CC), and analyzed the feed chemical properties of those SMS. As a result of cultivation test, CC and CSHP treatment took 27 days for spawn run, 4 days for primordium formation, and 3 days for development fruiting bodies, resulting in a total cultivation period of 34 days. The yield per bottle was 134 g for CC treatment, similar to 130 g for control, while CSHP treatment (112 g) and CSP treatment (68 g) were lower than that of control. The highest biological efficiency (BE) was shown in CC treatment as 80.1%, which was 11.4% higher than 68.7% of control. The SMS of CC treatment had a relatively low content of neutral detergent fiber and acid detergent fiber, and in particular, lignin content was the lowest and crude protein content was the highest among other treatments. Therefore, CC as a substitute material for sawdust was capable of stable mushroom production and excellent nutritional value as a feed for its by-products.

• Journal of Mushroom
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• v.20 no.4
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• pp.263-269
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• 2022

This study investigated the culture characteristics of Cryptoporus volvatus, whichis grow naturally in Korea, to determine the suitable environmental conditions for its cultivation. The physiological characteristics of the mycelia were assessed according to the cultivation conditions, to determine the optimal conditions for artificial cultivation. The visual characteristics of the hyphae of Cryptoporus volvatus KACC52303 included an irregular and uneven surface and a fuzzy or cotton-like texture. Under the microscope, its microstructure showed pre-chlamydospore formation, but no clamps were seen. The appropriate culture temperature was found to be a medium/high temperature of approximately 25-30℃, and the optimal pH was found to have a wide range from weakly acidic (pH 4) to neutral (pH 7). In the optimal nutrient source experiment, hyphal growth was shown to be fair in a mixed medium with 2.5% dextrin as the carbon source and 0.1% yeast extract as the organic nitrogen source. Among the various amino acids, organic acids, and inorganic salts tested, the fastest hyphal growth was observed in the presence of leucine, acetic acid or gluconic acid, and KCl or KH₂PO₄, respectively. The column test showed that the best mycelial growth occurred in a mixed medium of 80% pine sawdust, 10% rice bran, and 10% corncob sawdust.

• Journal of Mushroom
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• v.18 no.1
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• pp.120-124
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• 2020

This study was conducted to provide basic data for setting a standard medium for winter mushroom cultivation. Investigation of medium composition in winter mushroom farms in Korea revealed that the types of medium used for each farm were slightly different and that the mixing ratio of the medium also varied. All farmers used corncob, rice bran, and beet pulp as the main media, and calcium carbonate and ground oyster shells were used at 1.0~3.8% to adjust the pH of the medium. Analysis of the physicochemical properties of the mixed media showed nitrogen content of 1.28~1.52%, carbon content of 45.7~48.5%, and C/N ratio of 30.7~37.9. The content of inorganic components was significantly different in each farm, depending on the type and amount of minerals in the mixed medium. Mycelial growth was the fastest at Farm 2, reaching 6.5 cm within 34 days of culture, followed by Farm 4 at 5.7 cm, whereas Farm 1, 3, and 5 showed similar growth. Mycelial density was high without any significant difference between farms. Survey of yield according to medium composition in each farm showed the highest yield in Farm 2 at 173.4 g/bottle, followed by Farm 1 at 168.4 g/bottle, whereas Farm 3 and 4 showed similar yield. However, Farm 4 had the lowest yield at 145.4 g/bottle. Therefore, mushroom yield was different depending on the medium composition in the farm, and thus selection of a medium that can be used universally in multiple mushroom farms was considered possible.

• Journal of Practical Agriculture & Fisheries Research
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• v.20 no.1
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• pp.35-47
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• 2018

A edible mushroom, Clitocybe maxima (Lentinus giganteusis) commercially cultivated in China and Taiwan. However, the researches of cultivation and cultural characteristics were not reported in Korea. In this study, we conducted on cultural characteristics and artificial cultivation of C. maxima. Six isolates were collected from China(3 isolates, commercial strain), Taiwan(1 isolate, commercial strain) and Korea(2 isolates, wild type). C. maxima and L. giganteus collected in China and Taiwan, respectively, are the same in China and are estimated to be of the same species as cultured characteristics. The mycelial growth of the collected strains was not significantly different in agar medium but it showed the best growth in YPMG in liquid culture. Optimum temperature for mycelial growth and induction of fruit body were 25℃ and 30℃, respectively. In order to artificial cultivation of C. maxima, cultural characteristics and artificial cultivation were carried out using agricultural by-products and forestry by-products materials. Mycelial growth was suitable in rice straw, cottonwood sawdust, corncob and rice seed medium, and it was selected as a cultivation medium. The suitable medium for artificial cultivation of C. maxima was selected to mixed medium 2(compounding ratio(v/v): 55% of hardwood sawdust, 5% of cottonseed pellets, 10% of cottonseed, 15% of beet pulp, 15% of swollen rice husks). It took about 30 days to be able to harvest, it was faster than oyster mushrooms. The cultivation period was about 30days. A isolate, CMA-002 was not initiation to fruit body primordiuma on the used cultivation substrate. Other 5 isolates were initiate and development to fruit body on the substrate used in this study. The strain CMA-003 was initiated to be fruiting body by 8~10 days after induction of fruiting body in all of the substrates. Isolate CMA-003 was generate to a bundle fruit body. Other isolates, however, were form fruit body individually. The CMA-003 strain was likely highly recommendable strains for farming. The optimum conditions for the induction and growth of C. maxima fruit body were 25~30℃, 8 hr illumination per day with white fluorescent lamp, 90~95% relative humidity, and 1,500 ppm of CO₂ concentration in a cultivation room.