• Korean Journal of Food Science and Technology
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• v.14 no.2
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• pp.151-155
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• 1982

Effects of vitamins, metabolic intermediates and several inorganic mineral salts on the biomass and lipid accumulation of Mucor plumbeus were investigated after 15 days of incubation at $37^{\circ}C$ under static culture condition. The optimum concentrations of various vitamins were ${\gamma}/l$ for biotin, and 0.01 g/l for nicotinic acid, pyridoxine, thiamine and riboflavin. Among them pyridoxine was the most stimulatory. The maximum felt weight and lipid content per 50ml medium were $2.82{\pm}0.14\;g$ and 62.8%. Triglyceride content of neutral lipid produced under this condition was 64.9%. The major fatty acids were oleic acid (50.0%), linoleic (23.8%) and palmitic acid (13.9%). Malonic acid was considered not to be desirable even though it stimulated the biomass and lipid accumulation because triglyceride content was lowered considerably comparing with control. $MgSO_4{\cdot}7H_2O$ was the most stimulatory among the various magnesium salts and its optimum concentration was 5 g/l. Mucor plumbeus did not require $NaH_2PO_4$ for the stimulation of felt and lipid production. However, the addition of $MnCl_2$ at the concentration of 2 g/l was stimulatory to show $2.76{\pm}0.28\;g$ of felt/50 ml and 56.4% lipid content, and 73.9% triglyceride in the neutral lipid.

• Korean Journal of Food Science and Technology
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• v.21 no.6
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• pp.808-814
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• 1989

To produce ${\gamma}-linolenic$ acid by a mold, cultural conditions of Mortierella isabellina IFO 8183 were investigated. It was found that the increase of initial pH resulted in the decrease of the ${\gamma}-Linolenic$ acid content and the increase of the C/N ratio of medium resulted in the increase of the lipid content. Addition of sodium acetate into the medium resulted in the increased of cell yield, lipid yield, ${\gamma}-Linolenic$ acid content and ${\gamma}-Linolenic$ acid productivity. Under the optimum coditions(glucose, $NH_4NO_3$, C/N ratio of 40, pH 6.0, $30^{\circ}C$ and 0.5% of sodium acetate), the following results were obtained: cell yield, 0.347(g dry biomass/g glucose; lipid yield, 0.18(g lipid/g glucose); lipid content, 0.52(g lipid/g dry biomass); ${\gamma}-linolenic$ acid content, 60(mg ${\gamma}-linolenic$ acid/g lipid); maximum ${\gamma}-linolenic$ acid concentration, 347mg/l after incubation of 8 days.

• Korean Journal of Microbiology
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• v.42 no.2
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• pp.83-88
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• 2006

This research was performed to determine the production of lovastatin and its HMG-CoA reductase activity produced by fruit bodies and mycelial liquid cultures of domestic edible mushrooms (8 fungal strains). By deter-mining TLC analysis for the confirmation of the presence of lovastatin, all the extracts from fruit bodies and mycelial liquid culture showed same Rf value (0.46), whick was identical to that of the standard lovastatin. In order to extract lovastatin from fruit body, the mixture of water/acetonitrile/methanol was chosen as the most effective solvent. Extracts from fruit body and mycelial liquid culture of pleurotus ostreatus produced the high-est lovastatin 0.98 mg/g based on dry biomass, and 21.90 mg/L, respectively. In the inhibition rate of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase, the highest was obtained in P. ostreatus as 67.8% among fruit bodies, and the rates of mycelial liquid culture extracts from P. ostreatus and Laetiporus sulphureus were 37.2% and 29.1%, respectively. Unusually L. sulphureus showed high inhibition rate with low content of lovastatin due to the contribution of campesterol and gamma-sitosterol with hypocholesterolemic activity as metabolites.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.4
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• pp.36-47
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• 2009

Microbial and related biochemical mass of composts are important for optimization of its process and end-products. This study was carried out to assess the specific microbial and related biochemical mass which could be used as an indicator for compost maturity during composting stages. The samples from five compost plants were collected at three stages (Initial, Thermophilic and Mature) and analyzed for total aerobic bacteria (TAB), Coliforms, Escherichia coli, Actinomycetes and fungi. Significantly, the coliforms and E.coli counts decreased during the thermophilic stage and were completely eliminated during mature stage. However, the other microbial mass were completely eliminated during mature stage. Which disclosed that Coliforms and E.coli communities can be used as compost maturity indicator. Interestingly, the microbial biomass carbon and nitrogen ratio (MBC/MBN) were decreased a little during the thermophilic stage due to the decreasing number of coliforms, Ecoli and fungi, while the ratio increased during the mature stage due to increasing fungal and aerobic bacterial counts. In addition the heavy metals were shown strong negative correlation with Actenomycetes. This study provides insight to the evaluation of compost maturity as well as the quality by the metal-microbial interactions.

• Journal of Microbiology and Biotechnology
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• v.22 no.11
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• pp.1494-1500
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• 2012

Fermentation with filamentous fungi in a bioreactor is a complex dynamic process that is affected by flow conditions and the evolution of the rheological properties of the medium. These properties are mainly affected by the biomass concentration and the morphology of the fungus. In this work, the rheological properties of a fermentation with the fungus Beauveria bassiana under different hydrodynamic conditions were studied and the rheological behavior of this broth was simulated through a mixture of carboxymethyl cellulose sodium and cellulose fibers (CMCNa-SF). The bioreactor was a 10 L CSTR tank operated at different stir velocities. Rheological results were similar at 100 and 300 rpm for both systems. However, there was a significant increase in the viscosity accompanied by a change in the consistence index, calculated according to the power law model, for both systems at 800 rpm. The systems exhibited shear-thinning behavior at all stir velocities, which was determined with the power law model. The mixing time was observed to increase as the cellulose content in the system increased and, consequently, the efficiency of mixing diminished. These results are thought to be due to the rheological and morphological similarities of the two fungal systems. These results will help in the optimization of scale-up production of these fungi.

• Mycobiology
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• v.43 no.1
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• pp.49-56
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• 2015

The present study is the first report on the isolation of Penicillium menonorum from rhizosphere soil in Korea and its identification based on morphological characteristics and internal transcribed spacer gene sequence. The fungal isolate was named KNU-3 and was found to exhibit plant growth-promoting (PGP) activity through indole acetic acid (IAA) and siderophore production, as well as P solubilization. KNU-3 produced 9.7 mg/L IAA and solubilized 408 mg of $Ca_3PO_4/L$, and inoculation with the isolate significantly (p < 0.05) increased the dry biomass of cucumber roots (57%) and shoots (52%). Chlorophyll, starch, protein, and P contents were increased by 16%, 45%, 22%, and 14%, respectively, compared to plants grown in uninoculated soil. The fungus also increased soil dehydrogenase (30%) and acid phosphatase (19%) activities. These results demonstrate that the isolate KNU-3 has potential PGP attributes, and therefore it can be considered as a new fungus to enhance soil fertility and promote plant growth. Moreover, the discovery of PGP ability and traits of this fungus will open new aspects of research and investigations. In this study, plant growth promotion by P. menonorum KNU-3 is reported for the first time in Korea after its original description.

• Journal of Ecology and Environment
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• v.44 no.2
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• pp.72-80
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• 2020

Background: Antibiotics are widely used to treat animals from infections. After fertilizing, antibacterials can remain in the soil while adversely affecting the soil microorganisms. The concentration of oxytetracycline (OTC) in the soil and its effect on the soil microbial community was assessed. To assess the impact of OTC on the soil microbial community, it was added to the soil at concentrations of 50, 150, and 300 mg kg^-1 and incubated for 35 days. Results: The concentration of OTC added to the soil decreased from 150 to 7.6 mg kg^-1 during 30 days of incubation, as revealed by LC-MS. The deviations from the control values in the level of substrate-induced respiration on the 5th day of the experiment were, on average, 26, 68, and 90%, with OTC concentrations at 50, 150, and 300 mg kg^-1, respectively. In samples with 150 and 300 mg kg^-1 of OTC, the number of bacteria from the 3rd to 14th day was 2-3 orders of magnitude lower than in the control. The addition of OTC did not affect the fungal counts in samples except on the 7th and 14th days for the 150 and 300 mg kg^-1 contaminated samples. Genes tet(M) and tet(X) were found in samples containing 50, 150, and 300 mg kg^-1 OTC, with no significant differences in the number of copies of tet(M) and tet(X) genes from the OTC concentration. Conclusions: Our results showed that even after a decrease in antibiotic availability, its influence on the soil microbial community remains.

• Korean Journal Plant Pathology
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• v.13 no.4
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• pp.215-218
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• 1997

The environmental factors affecting maturity of pseudothecia overwintered in iufected leaves by Mycosphaserella nawae was investigated. The pseudothecia in the overwinteringinfected leaves were matured at the end of April when the average temperature was $14^{\circ}C$ and precipitation was enough. Pseudothecia initiation was preceded by the fungal biomass development in a given host. The maturity of the pseudothecia from the leaves defoliated in early October was earlier and higher than those defoliated in November of the previous year. Pseudothecia development was also positively affected by low temperature. The maturity time, as determined by percentage of matured pseudothecia out of prematured ones, was also 20 days earlier, and the rate of maturity was higher for the leaves overwintered in door, than for those kept in greenhouse. We have providedevidence that the conidia play a significant role in the epidemiology of this pathogen. Many pseudothecia were developed in the leaves infected by artificially inoculated conidia and maturation rate of the pseudothecia was not different from that of the typical symptom by ascospores infection of Mycosphaerella nawae.

• Journal of the Korean Wood Science and Technology
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• v.35 no.6
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• pp.159-165
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• 2007

An extracellular xylanase from the brown-rot fungus Fomitopsis palustris grown on rice straw culture was purified to a single protein band. On SDS-PAGE, the molecular mass of purified enzyme was estimated to be about 43 kDa. The amino acid sequence of the proteolytic fragments showed high homology with fungal glycoside hydrolase family 10 xylanases. The $K_m$, $K_{cat}$ and $V_{max}$ for birch xylan were $31mg/m{\ell}$, $2.3{\times}10^4/min$ and 252.3 U/mg, respectively. The optimal activity of the purified xylanase from F palustris was observed at pH 4.0~5.0 and $70^{\circ}C$.

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.19-19
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• 2014

Pleurotus ostreatus, P. eryngii, and Flammulina velutipes are major edible mushrooms that account for over 89% of total mushroom production in Korea. Recently, Agrocybe cylindracea, Hypsizygus marmoreus, and Hericium erinaceu are increasingly being cultivated in mushroom farms. In Korea, the production of edible mushrooms was estimated to be 614,224 ton in 2013. Generally, about 5 kg of mushroom substrate is needed to produce 1 kg of mushroom, and consequently about 25 million tons of spent mushroom substrate (SMS) is produced each year in Korea. Because this massive amount of SMC is unsuitable for reuse in mushroom production, it is either used as garden fertilizer or deposited in landfills, which pollutes the environment. It is reasonably assumed that SMS includes different secondary metabolites and extracellular enzymes produced from mycelia on substrate. Three major groups of enzymes such as cellulases, xylanases, and lignin degrading enzymes are involved in breaking down mushroom substrates. Cellulase and xylanase have been used as the industrial enzymes involving the saccharification of biomass to produce biofuel. In addition, lignin degrading enzymes such as laccases have been used to decolorize the industrial synthetic dyes and remove environmental pollutions such as phenolic compounds. Basidiomycetes produce a large number of biologically active compounds that show antibacterial, antifungal, antiviral, cytotoxic or hallucinogenic activities. However, most previous researches have focused on therapeutics and less on the control of plant diseases. SMS can be considered as an easily available source of active compounds to protect plants from fungal and bacterial infections, helping alleviate the waste disposal problem in the mushroom industry and creating an environmentally friendly method to reduce plant pathogens. We describe extraction of lignocellulytic enzymes and antimicrobial substance from SMSs of different edible mushrooms and their potential applications.