• KSBB Journal
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• v.5 no.4
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• pp.383-390
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• 1990

Alcoholic distillery waste was utilized as dual purposes to produce citric acid and to reduce the amount of waste to be treated. Enzyme and acid hydrolysis of this waste were studied to suggest effective way of present purpose. Enzymatic hydrolysis of this naked barley alcoholic distillery waste by $\alpha$-and $\beta$-amylase gave glucose as 8g/l concentration at $55^{\circ}C$ for 6 hours, which produced 1g/l citric acid and 5.33g/l mycelial. This waste material hydrolyzed with 25% HCl at $120^{\circ}C$ showed 21.5g/l glucose and produced 1.75g/l citric acid with 4.9g/1 mycelial. The glucose concentration was decreased to 3.44g/l by further 2nd acid hydrolysis because the monosugars were decomposed at prolonged hydrolysis conditions. The addition of 3g/l $NH_4NO_3$ increased the mycelial growth but reduced the amount of citric acid formed. The formation of citric acid was increased at low concentration of manganese ion.

• Korean Chemical Engineering Research
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• v.48 no.6
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• pp.704-711
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• 2010

Lignocellulose ($2^{nd}$ generation) is difficult to hydrolyze due to the presence of lignin and the technology developed for cellulose fermentation to ethanol is not yet economically viable. However, recent advances in the extremely new field of biotechnology for the ethanol production are making it possible to use of agriculture residuals and nonedible crops biomass, e.q., rice straw and miscanthus sinensis, because of their several superior aspects as agriculture residual and nonedible crops biomass; low lignin, high contents of carbohydrates. In this article, as the basic study of AP(Ammonia Percolation), the properties and the optium conditions of process were established, and then the overall efficiency of AP was investigated. The important independent variables for AP process were selected as ammonia concentration, reaction temperature, and reaction time. The percolation condition for maximizing the content of cellulose, the enzymatic digestibility, and the lignin removal was optimized using RSM(Response Surface Methodology). The determined optimum condition is ammonia concentration; 11.27%, reaction temperature; $157.75^{\circ}C$, and reaction time; 10.01 min. The satisfying results were obtained under this optimized condition, that is, the results are as follows: cellulose content(relative); 39.98%, lignin content(relative); 8.01%, and enzymatic digestibility; 85.89%.

• Korean Journal of Agricultural Science
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• v.22 no.2
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• pp.143-150
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• 1995

In order to find a way to utilize paper mill sludge, its composting was conducted with anaerobic waste of kraft paper sludge, raw kraft paper sludge, and CMC sludge(CMC : Sodium Carboxymethylcellulose) under aerobic condition at $50^{\circ}C$. It took 3 days for initial fermentation with anaerobic waste and CMC sludge, and six days with raw kraft paper sludge. Each compost was applied to radish(Rhaphanus Stativus L.), and absorption rate of staple nutrients increased 6.7~9.3 times higher in N, 17~21 times in P and 2~3 times in K than control at the harvesting stage. Also, organic matter contents were increased 1.5~2.3 times 4.5~5.3 times in CEC compared to control soil.

• 한국균학회소식:학술대회논문집
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• 2018.05a
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• pp.44-44
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• 2018

Fusarium head blight (FHB) caused by infection with Fusarium graminearum leads to enormous losses to crop growers, and may contaminate grains with a number of Fusarium mycotoxins that pose serious risks to human and animal health. Antagonistic bacteria that are used to prevent FHB offer attractive alternatives or supplements to synthetic fungicides for controlling FHB without the negative effects of chemical management. Out of 500 bacterial strains isolated from soil, Bacillus amyloliquefaciens JCK-12 showed strong antifungal activity and was considered a potential source for control strategies to reduce FHB. B. amyloliquefaciens JCK-12 produces several cyclic lipopeptides (CLPs) including iturin A, fengycin, and surfactin. Iturin A inhibits spore germination of F. graminearum. Fengycin or surfactin alone did not display any inhibitory activity against spore germination at concentrations less than 30 ug/ml, but a mixture of iturin A, fengycin, and surfactin showed a remarkable synergistic inhibitory effect on F. graminearum spore germination. The fermentation broth and formulation of B. amyloliquefaciens JCK-12 strain reduced the disease incidence of FHB in wheat. Furthermore, co-application of B. amyloliquefaciens JCK-12 and chemical fungicides resulted in synergistic in vitro antifungal effects and significant disease control efficacy against FHB under greenhouse and field conditions, suggesting that B. amyloliquefaciens JCK-12 has a strong chemosensitizing effect. The synergistic antifungal effect of B. amyloliquefaciens JCK-12 and chemical fungicides in combination may result from the cell wall damage and altered cell membrane permeability in the phytopathogenic fungi caused by the CLP mixtures and subsequent increased sensitivity of F. graminearum to fungicides. In addition, B. amyloliquefaciens JCK-12 showed the potential to reduce trichothecenes mycotoxin production. The results of this study indicate that B. amyloliquefaciens JCK-12 could be used as an available biocontrol agent or as a chemosensitizer to chemical fungicides for controlling FHB disease and as a strategy for preventing the contamination of harvested crops with mycotoxins.

• Journal of Life Science
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• v.18 no.1
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• pp.52-57
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• 2008

Xylan is a major hemicellulose component of the cell walls of monocots and hardwood, representing up to 30% of the dry weight of these plants. To efficiently hydrolyze xylan, the endoxylanase gene from Bacillus sp. was expressed in B. subtilis DB431 by introducing the plasmid pJHKJ4. The total activity of the recombinant endoxylanase reached about 857 unit/ml by batch fermentation of B. subtilis DB431/pJHKJ4 in LB maltose medium. The majority (>92%) of endoxylanase was efficiently secreted into the culture medium. The recombinant endoxylanase hydrolyzed more the birchwood xylan efficiently than the other xylans. When 4 % concentration of xylan was used, the highest production of xylooligosaccharide was observed, and xylobiose and xylotriose were the major products. Optimal amount of enzyme and reaction time for producing xylooligosaccharide were found to be 10 unit and 1 hr, respectively. In addition, the temperature of $40^{\circ}C{\sim}50^{\circ}C$ gave the highest production of xylooligosaccharide. Consequently, the optimized conditions for the production of xylooligosaccharide through the hydrolysis of xylan were determined as follows: 10 unit endoxylanase, $50^{\circ}C$, 4% birchwood xylan, 1 hr reaction.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.5
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• pp.519-524
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• 2005

Due to the low C/N ratio of domestic wastewater characteristic, addition of external carbon source for the effective N and P removal is necessary. High organic content of food waste can be used for the external carbon source in biological nutrient removal processes, The applicability of condensate of food waste (CFW), which is produced during the high-rate fermentation process, was examined in membrane bioreactor for the nutrient removal. Under the various operating conditions, nutrient removal efficiencies and membrane fouling characteristics were evaluated using synthetic wastewater. From nitrate utilization rate (NUR) test, denitrification rate was 0.19 g $NO_3-N/g$ VSS/day. With the addition of CFW increased, average removal efficiencies of T-N and T-P could be increased up to 64% and 41%, respectively. Also the optimal retention time was 3 hr/5 hr for anoxic/aerobic reactor. When applied to real sewage, membrane fouling resistance was increased up to 60%, which could be reduced from $10.4{\times}10^{12}m^{-1}$ to $5.9{\times}10^{12}m^{-1}$ with the control of influent suspended solid concentration. In summary, it was suggested that CFW could be used as an economical and effective carbon source for membrane assisted biological N and P removal.

• Journal of Microbiology and Biotechnology
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• v.23 no.2
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• pp.211-217
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• 2013

Corynebacterium glutamicum is one of the well-studied industrial strain that is used for the production of nucleotides and amino acids. Recently, it has also been studied as a possible producer of organic acids such as succinic acid, based on its ability to produce organic acids under an oxygen deprivation condition. In this study, we conducted the optimization of medium components for improved succinate production from C. glutamicum under an oxygen deprivation condition by Plackett-Burman design and applied a response surface methodology. A Plackett-Burman design for ten factors such as glucose, ammonium sulfate, magnesium sulfate, potassium phosphate ($K_2HPO_4$ and $KH_2PO_4$), iron sulfate, manganese sulfate, biotin, thiamine, and sodium bicarbonate was applied to evaluate the effects on succinate production. Glucose, ammonium sulfate, magnesium sulfate, and dipotassium phosphate were found to have significant influence on succinate production, and the optimal concentrations of these four factors were sequentially investigated by the response surface methodology using a Box-Behnken design. The optimal medium components obtained for achieving maximum concentration of succinic acid were as follows: glucose 10 g/l, magnesium sulfate 0.5 g/l, dipotassium phosphate ($K_2HPO_4$) 0.75 g/l, potassium dihydrogen phosphate ($KH_2PO_4$) 0.5 g/l, iron sulfate 6 mg/l, manganese sulfate 4.2 mg/l, biotin 0.2 mg/l, thiamine 0.2 mg/l, and sodium bicarbonate 100 mM. The parameters that differed from a normal BT medium were glucose changed from 40 g/l to 10 g/l, dipotassium phosphate ($K_2HPO_4$) 0.5 g/l changed to 0.75 g/l, and ammonium sulfate ($(NH_4)_2SO_4$) 7 g/l changed to 0 g/l. Under these conditions, the final succinic acid concentration was 16.3 mM, which is about 1.46 fold higher than the original medium (11.1 mM) at 24 h. This work showed the improvement of succinate production by a simple change of media components deduced from sequential optimization.

• Journal of Microbiology and Biotechnology
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• v.23 no.4
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• pp.499-510
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• 2013

Among 25 isolates, Aspergillus fumigatus ASH (JX006238) was identified as a potent producer of homocysteine ${\gamma}$-lyase. The nutritional requirements to maximize the enzyme yield were optimized under submerged (SF) and solid-state fermentation (SSF) conditions, resulting in a 5.2- and 2.3-fold increase, respectively, after the last purification step. The enzyme exhibited a single homogenous band of 50 kDa on SDS-PAGE, along with an optimum pH of 7.8 and pH stability range of 6.5 to 7.8. It also showed a pI of 5.0, as detected by pH precipitation with no glycosyl residues. The highest enzyme activity was obtained at $37-40^{\circ}C$, with a $T_m$ value of $70.1^{\circ}C$. The enzyme showed clear catalytic and thermal stability below $40^{\circ}C$, with $T_{1/2}$ values of 18.1, 9.9, 5.9, 3.3, and 1.9 h at $30^{\circ}C$, $35^{\circ}C$, $40^{\circ}C$, $50^{\circ}C$, and $60^{\circ}C$, respectively. Additionally, the enzyme $K_r$ values were 0.002, 0.054, 0.097, 0.184, and 0.341 $S^{-1}$ at $30^{\circ}C$, $35^{\circ}C$, $40^{\circ}C$, $50^{\circ}C$, and $60^{\circ}C$, respectively. The enzyme displayed a strong affinity to homocysteine, followed by methionine and cysteine when compared with non-S amino acids, confirming its potency against homocysteinuria-related diseases, and as an anti-cardiovascular agent and a specific biosensor for homocysteinuria. The enzyme showed its maximum affinity for homocysteine ($K_m$ 2.46 mM, $K_{cat}\;1.39{\times}10^{-3}\;s^{-1}$), methionine ($K_m$ 4.1 mM, $K_{cat}\;0.97{\times}10^{-3}\;s^{-1}$), and cysteine ($K_m$ 4.9 m M, $K_{cat}\;0.77{\times}10^{-3}\;s^{-1}$). The enzyme was also strongly inhibited by hydroxylamine and DDT, confirming its pyridoxal 5'-phosphate (PLP) identity, yet not inhibited by EDTA. In vivo, using Swiss Albino mice, the enzyme showed no detectable negative effects on platelet aggregation, the RBC number, aspartate aminotransferase, alanine aminotransferase, or creatinine titer when compared with negative controls.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.1
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• pp.9-15
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• 2006

As a part of the investigation for utilizing pearl oyster by-products, a rapid salt-fermented pearl oyster using commercial enzyme was prepared and also examined on the characteristics. The salt-fermented pearl oyster prepared by optimal condition, which was prepared by mixing of minced pearl oyster, 15% salt, and 1% $Protamex^\circledR$ and fermented for 4 weeks, was superior in hydrolysis degree (28.7%) and ACE inhibitory activity (92.6%) to salt-fermented pearl oyster prepared by other conditions, such as the use of whole tissue, different enzymes $(Alcalase^\circledR,\;Neutrase^\circledR\;and\;Flavourzyme^\circledR)$, different salt concentrations (20 and 25%), and different fermentation periods (2, 6 and 8 weeks). There were, however, some shortcomings with this product. It showed a dark green color and an unfavorable bitter taste. These shortcomings were improved by the addition of seasoning paste. The calcium and phosphorus contents of the seasoned salt-fermented pearl oyster were 64.2 mg/100 g and 71.6 mg/100 g, respectively, and the calcium content based on phosphorus was a good ratio for absorbing calcium. The total amino acid content of the seasoned and salt-fermented pearl oyster was 7,054 mg/100 g and the major amino acids ware aspartic acid (555.1 mg/100 g), glutamic acid (1,131.2 mg/100 g), alanine (658.2 mg/100 g), and lysine (695.5 mg/100 g). The seasoned salt-fermented pearl oyster, along with angiotensin I converting enzyme (ACE) inhibitory activity (98.3%), also showed a recognizable level (87.5%) of anti-oxidative activity.

• 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.