• KSBB Journal
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• v.9 no.4
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• pp.378-384
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• 1994

An improved method for the selective isolation of high-yielding mutant strains for the production of antifungal antibiotic KRF-001 was investigated. The mutant strain U. V 4, which produces high titer of KRF-001, was selected on the high potency agar plate after ultraviolet light irradiation. The U. V 4 strain produced 2-fold more KRF-001 than the mother strain in production media. Large scale fermentation was performed using the U. V 4 strain in 100$\ell$ fermenter. The antifungal antibiotic KRF-001 secreted into culture broth was detected by HPLC in 24hrs of fermentation.

• KSBB Journal
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• v.17 no.1
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• pp.73-79
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• 2002

The method to optimize the microbial production of ethanol from CO using Clostridium ljungdahlii was developed. The kinetic parameter study on CO conversion with Clostridium ljungdahlii was carried out and maximum CO conversion rate of 37.14 mmol/L-hr-O.D. and $K_{m}$ / of 0.9516 atm were obtained. It was observed that method of two stage fermentation, which consists of cell growth stage and ethanol production stage, was effective to produce ethanol. When pH was shifted from 5.5 to 4.5 and ammonium solution was supplied to culture media as nitrogen source at ethanol production stage, the concentration of ethanol produced was increased 20 times higher than that without shift. Ethanol production from CO in a fermenter with Clostridium ljungdahlii was optimized and the concentration of ethanol produced was 45 g/L and maximun ethanol productivity was 0.75 g ethanol/L-hr.

• The Korean Journal of Mycology
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• v.47 no.4
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• pp.359-371
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• 2019

To optimize the expression and secretion of ferritin protein associated with ion storage in the mushroom, Pleurotus eryngii, a recombinant secretion vector, harboring the ferritin gene, was constructed using a pPEVPR1b vector under the control of the CaMV 35S promoter and signal sequence of pathogen related protein (PR1b). The ferritin gene was isolated from the T-Fer vector following digestion with EcoRI and HindIII. The gene was then introduced into the pPEVPR1b secretion vector, and it was then named pPEVPR1b-Fer. The recombinant vector was transferred into P. eryngii via Agrobacterium tumefaciens-mediated transformation. The transformants were selected on MCM medium supplemented with kanamycin and its expression was confirmed by SDS-PAGE and western blotting. Expression of ferritin protein was optimized by modifying the culture conditions such as incubation time and temperature in batch and 20 L airlift type fermenter. The optimal conditions for ferritin production were achieved at 25℃ and after incubating for 8 days on MCM medium. The amount of ferritin protein was 2.4 mg/g mycelia, as measured by a quantitative protein assay. However, the signal sequence of PR1b (32 amino acids) seems to be correctly processed by peptidase and ferritin protein may be targeted in the apoplast region of mycelia, and it might not be secreted in the culture medium. The iron binding activity was confirmed by Perls' staining in a 7.5% non-denaturing gel, indicating that the multimeric ferritin (composed of 24 subunits) was formed in P. eryngii mycelia. Mycelium powder containing ferritin was tested as a feed additive in broilers. The addition of ferritin powder stimulated the growth of young broilers and improved their feed efficiency and production index.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.3
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• pp.376-380
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• 2006

An experiment was conducted to study the effect of temperature and pH on in vitro nutrient degradability, volatile fatty acid profile and methane production. The fermenter used was the semi-continuous system, known as the rumen simulation technique (RUSITEC). Sixteen cylinders were used at one time with a volume of 800 ml, the dilution rate was set at 3.5%/hour, the infused buffer being McDougall's artificial saliva. Basal diet (9.6 g DM) used in RUSITEC consisted of (DM) 6.40 g Timothy hay, 1.86 g crushed corn and 1.34 g soybean meal. The food for the fermentation vessel was provided in nylon bags, which were gently agitated in the liquid phase. The experiment lasted for 17 d with all the samples taken during the last 5 d. Treatments were allocated at random to four vessels each and were (1) two temperature levels of $39^{\circ}C$ and $41^{\circ}C$ (2) two pH levels of 6.0 and 7.0. The total diet contained ($g\;kg^{-1}$ DM) 957 OM, 115 CP and $167MJ\;kg^{-1}$ (DM) GE. Although increase in temperature from $39^{\circ}C$ to $41^{\circ}C$ reduced degradation of major nutrients in vitro, it was non-significant. Interaction effect of temperature with pH also reflected a similar trend. However, pH showed a significant (p<0.05) negative effect on the degradability of all the nutrients in vitro. Altering the in vitro pH from 7 to 6 caused marked reduction in DMD from 60.2 to 41.8, CPD from 76.3 to 55.3 and GED from 55.3 to 35.1, respectively. Low pH (6) depressed total VFA production (61.9 vs. 34.9 mM) as well as acetate to propionate ratio in vitro (from 2.0 to 1.5) when compared to pH 7. Compared to pH 7, total gas production decreased from 1,841 ml to 1,148 ml at pH 6, $CO_2$ and $CH_4$ production also reduced from 639 to 260 ml and 138 to 45 ml, respectively. This study supported the premise that pH is one of the principal factors affecting the microbial production of volatile fatty acids and gas. Regulating the ruminal pH to increase bacterial activity may be one of the methods to optimize VFA production, reduce methane and, possibly, improve animal performance.

• The Korean Journal of Mycology
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• v.48 no.1
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• pp.15-27
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• 2020

In screening for antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) KCCM 40510 and Bacillus cereus KCTC 3624, NNIBRFG5039 was isolated from the air in Sangju-si, Gyeongsangbuk-do. Based on a high sequence similarity of the internal transcribed spacer (ITS) region, NNIBRFG5039 was determined to be closely related to Penicillium rubefaciens CBS 139145. The optimal media, initial pH, and temperature for mycelial growth and antimicrobial activity of P. rubefaciens NNIBRFG5039 were determined as follows: potato dextrose broth (PDB), pH 6.5, and 30℃, respectively. Under the optimal culture conditions, maximum mycelial growth (12.4 g L^-1) and antibacterial activity (7.5 mm zone of inhibition against MRSA KCCM 40510, and 5.0 mm zone of inhibition against B. cereus KCTC 3624) were observed in a 5 L stirred-tank fermenter. We also isolated the antimicrobial compound from an ethyl acetate fraction, and its chemical structure was identified as (S)-6-hydroxymellein (1) by ESI-MS, ¹H-NMR, and ¹³C-NMR. Consequently, the extract from P. rubefaciens NNIBRFG5039 may be used in functional materials for antimicrobial-related applications.

• Korean Journal of Food Science and Technology
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• v.4 no.3
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• pp.200-205
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• 1972

Effects of several different petroleum fractions (LGO, HGO, VGO, Diesel oil, SP(E), HGO-wax, L/M-wax), stepwise addition of calculated amounts of HGO at defined intervals, recycling of spent media on cell growth of Candida tropicalis KIST 351 were studied using $2.5{\ell}$ fermenter by batch process. In addition, continuous cultivation of the yeast was also performed in the light of biomass production using $28{\ell}$ fermenter with LGO. 1) Cell concentration, yield on the basis of gas oil and n-paraffin with the petroleum fractions were in the range of $11{\sim}15g/{\ell}$, $10{\sim}12%$ and $77{\sim}82%$, respectively. 2) By stepwise addition of the gas oil, cell concentration and yield on the oil were increased up to 18.9 g/land 13%, respectively. 3) Spent medium slowed emulsifying ability of hydrocarbon and stimulating effect on the cell growth. Without additional supplementation of $Mg^{++}$ up to 20% of spent medium could be reused, while by adding of the $Mg^{++}$, 50% of medium could be recycled. 4) Optimum condition of continuous cultivation for biomass production was attained at the dilution rate of $D=0.1{\sim}0.125\;hr^{-1}$. Maximum yield coefficient on consumed n-paraffin was 0.94 at $D=0.1\;hr^{-1}$, however, 24% of supplied n-paraffin in the media was not utilized at this dilution rate.

• The Korean Journal of Mycology
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• v.33 no.1
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• pp.22-29
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• 2005

The main objectives of this research were to study the cultural and nutritional characteristics of Tricholoma matsutake and to establish its liquid culture system. The optimum growth of T. matsutake was observed in HA and TMM agar media. Similarly highest growth was observed in PDB and TMM liquid media. The optimal temperature for the mycelial growth was $25^{\circ}C$. The most suitable carbon source was dextrin among 12 different carbon sources tested. Yeast extract and peptone were best nitrogen sources among 17 different sources tested. The optimum mineral salts were $Fe_{2}(SO_{4})_{3}{\cdot}H_{2}O$ and KCl among 9 different sources tested. Shaking culture gave higher mycelial growth compared to stationary culture. Similarly, optimum medium amount for shaking culture was 100 ml per 250 ml flask. The highest mycelial growth was obtained when $5{\sim}7$ mycelial discs were inoculated in 100 ml of medium and incubated for $8{\sim}9$ weeks, respectively. The highest proportion of mycelial growth was observed at 40 : 1 ratio of medium to inoculum volume in 8 l air-lift fermenter.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.6
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• pp.899-903
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• 2005

One of the most important volatile aroma compounds responsible for mushroom flavor is 1-octen-3-ol. To meet the demand for natural mushroom flavor, a study was needed for the production of natural chiral specific (-)-1-octen-3-ol that has higher flavor intensity than synthetic chiral mixtures of (+), and (-)-1-octen-3-ol. The biosynthesis of (-)-1-octen-3-ol was achieved by an aerobic oxidation using lipoxygenase (LOX) and hydroperoxide lyase (HPOL) isolated from commercially available mushrooms in Korean market. Safflower oil from Uiseong, Gyeongsangbuk-do, that contains $\geq75\%$ of linoleic acid, was hydrolyzed using lipase. The recovered linoleic acid was biotransformed to stereo-specific 10-hydroperoxy linoleic acid by LOX. 10- hydroperoxy linoleic acid was further cleaved to (-)-1-octen-3-ol by HPOL. A commercial bioprocess for the production of (-)-1-octen-3-ol was developed using a 5-liter jar fermenter with fruiting bodies of Agaricus bisporus harvested from Buyeo, Chungcheongnam-do. The maximum production of (-)-1-octen-3-o1 was achieved at $4^{\circ}C$, pH 6.5 and 800 rpm yielding 748 mg/kg of mushroom.

• Journal of Microbiology and Biotechnology
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• v.21 no.6
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• pp.652-658
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• 2011

The growth kinetics of Streptomyces noursei NRRL 5126 was investigated under different aeration and agitation combinations in a 5.0 l stirred tank fermenter. Poly-${\varepsilon}$-lysine biosynthesis, cell mass formation, and glycerol utilization rates were affected markedly by both aeration and agitation. An agitation speed of 300 rpm and aeration rate at 2.0 vvm supported better yields of 1,622.81 mg/l with highest specific productivity of 15 mg/l.h. Fermentation kinetics performed under different aeration and agitation conditions showed poly- ${\varepsilon}$-lysine fermentation to be a growth-associated production. A constant DO at 40% in the growth phase and 20% in the production phase increased the poly-${\varepsilon}$-lysine yield as well as cell mass to their maximum values of 1,992.35 mg/l and 20.73 g/l, respectively. The oxygen transfer rate (OTR), oxygen utilization rate (OUR), and specific oxygen uptake rates ($qO_2$) in the fermentation broth increased in the growth phase and remained unchanged in the stationary phase.

• Journal of the East Asian Society of Dietary Life
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• v.1 no.2
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• pp.115-127
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• 1991

Information on brew time for Samhaeju can get from the 26 kinds of classical literature, which deal with Samhaeju. Usually, Samhaeju is brewed on any day of the Boar in January of the lunar calendar. However, any day of the Boar in a year seams to be possible for the brew time. In the first step of the manufacture procedure, nonglutinous and glutinous rice are used with the same propontion. The nonglutious and glutinous rice ratio become higher on the 2nd and the 3rd step than in the 1st step. The amount of water adding to the Samhaeju-base is increased step by step. In the first step, processing type of the cereal is predominantly gruel type, which is followed by rice calce. In the 2nd step, rice cake and doughnut-type rice cake are more common type than gruel type. In the 3rd step, processing type of the cereal in Samhaeju is mostly steamed water-soaked rice. Companing China and Japan with Korea, there is difference in the processing types of the cereal. They use steamed water-soaked rice in any step. Nuruk(fermenter) is added to the cold processed cereal in the first step.