• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.17 no.3
• /
• pp.170-176
• /
• 1984

This study was directed to define the taste compounds of crucian carp, Carassius caressius, free amino acids, nucleotides and their related compounds, organic bases, sugars, organic acids and minerals in the extracts of crucian carp were analyzed, and then followed by sensory evaluation of synthetic extracts prepared from 44 pure chemicals on the basis of the analytical data. Taste panel assessments of synthetic extracts prepared with each extractive component omitted were carried out by a triangle difference test, and changes in taste profile were assessed. In free amino acid composition, histidine was dominant occupying $46\%$ of the total free amino acids. The other abundant free amino acids were glycine, lysine, alanine and taurine. As for the nucleotides, IMP was dominant showing about $80\%$ of the total of nucleotides. The most abundant organic base was total creatinine. The content of betaine was poor and TMAO were trace in content. The main organic acids were succinic, propionic, butyric and valeric acid. Small amount of glucose, fructose and inositol were detected and ribose and arabinose were trace in content $K^+,\;Na^+,\;PO_4^{3-}\;and\;Cl^-$ were found to be the major ions and small amount of $Ca^{++}\;and\;Mg^{2+}$ were deleted. Judging from the results of omission test, the major components which contribute to produce the taste were serine, glutamic acid, lysine, arginine, tyrosine, phenylalanine, IMP, $Na^+,\;K^+\;and\;PO_4^{3-}$.

• Journal of Bio-Environment Control
• /
• v.29 no.2
• /
• pp.141-152
• /
• 2020

The rapid on-site measurement of hydroponic nutrients allows for the more efficient use of crop fertilizers. This paper reports on the development of an embedded on-site system consisting of multiple ion-selective electrodes (ISEs) for the real-time measurement of the concentrations of macronutrients in hydroponic solutions. The system included a combination of PVC ISEs for the detection of NO₃, K, and Ca ions, a cobalt-electrode for the detection of H₂PO₄, a double-junction reference electrode, a solution container, and a sampling system consisting of pumps and valves. An Arduino Due board was used to collect data and to control the volume of the sample. Prior to the measurement of each sample, a two-point normalization method was employed to adjust the sensitivity followed by an offset to minimize potential drift that might occur during continuous measurement. The predictive capabilities of the NO₃ and K ISEs based on PVC membranes were satisfactory, producing results that were in close agreement with the results of standard analyzers (R² = 0.99). Though the Ca ISE fabricated with Ca ionophore II underestimated the Ca concentration by an average of 55%, the strong linear relationship (R² > 0.84) makes it possible for the embedded system to be used in hydroponic NO₃, K, and Ca sensing. The cobalt-rod-based phosphate electrodes exhibited a relatively high error of 24.7±9.26% in the phosphate concentration range of 45 to 155 mg/L compared to standard methods due to inconsistent signal readings between replicates, illustrating the need for further research on the signal conditioning of cobalt electrodes to improve their predictive ability in hydroponic P sensing.

• Korean Journal of Agricultural Science
• /
• v.43 no.2
• /
• pp.176-185
• /
• 2016

This research was conducted to evaluate various levels of dolomitic lime incorporated as pre-planting fertilizers on the growth of red-leaf lettuce. To achieve this, three root media were formulated by mixing coir dust with expanded rice hull (CD+ERH, 8:2, v/v), carbonized rice hull (CD+CRH, 6:4, v/v), and ground pine bark (CD+GRPB, 6:4, v/v). During formulation, equal amounts of essential nutrients, except dolomitic lime, were incorporated into all root media and the levels of dolomitic lime were varied from 0 to $7.5g\;L^{-1}$ at 1.5 g increments. Seedlings of red-leaf lettuces at the 3rd leaf stage were transplanted into each medium treatment. Crop growths were measured 5 weeks after transplant and soil solutions were collected every week and analyzed for pH, EC, and nutrient concentrations. The treatments showing the heaviest fresh and dry weights in CD+ERH, CD+CRH, and CD+GRPB were 4.5 g, 4.5 g, and $7.5g\;L^{-1}$ of dolomite, respectively. The pHs of three root media yielding the highest crop growths were in the ranges of 6.4 to 7.1. These ECs in CD+CRH medium were around $1.0dS\;m^{-1}$ higher than those of CD+ERH and CD+GRPB when application rates of dolomitic lime were equal. $K^+$ concentrations were higher than $Ca^{+2}$ and $Mg^{+2}$ concentrations until week 2 in three root media. But $Ca^{+2}$ and $Mg^{+2}$ concentrations were higher than $K^+$ concentrations after week 3 in all root media. The concentrations of $PO_4{^{-3}}$ in all root media got abruptly lower until week 2. These results indicate that appropriate levels of dolomitic lime, as pre-planting nutrient charge fertilizers in CD+ERH and CD+GRPB media, are 4.5 and $7.5g\;L^{-1}$, respectively.

• Journal of Korean Society of Water and Wastewater
• /
• v.18 no.2
• /
• pp.137-144
• /
• 2004

In this study, several series of experiments were conducted to investigate the phosphorus (P) removal process in slag-containing solution using furnace and converter slags. High amount of $OH^-$, $Ca^{2+}$ and alkalinity were discharged from the slags and hydroxyapatites [$Ca_5(PO_4)_3(OH)$] were kept accumulated on the surface of slag. P removal capacity of the slag decreased with the increase of slag dosage. The maximum capacity was found to be 11.25 mg/g at the converter slag. Converter slag adsorbed P more than furnace slag(about four times in average). An experimental study on the effect of pH shows that the percentage removal of P increased upto 30% at the pH range of 56 than that of above pH 8. Langmuir isotherm constants gave a better correlation than Freundlich ones. P removal amount in the presence of $NH^+_4$ was less compared to the one in the absence of $NH^+_4$. Maximum percentage reduction was 23%.

• Journal of the Korean Chemical Society
• /
• v.42 no.6
• /
• pp.618-628
• /
• 1998

Pure CaO, Mn-doped CaO, Mn/CaO, and K/CaO catalysts were prepared and tested as catalysts for the oxidative coupling of methane in the temperature range of 600 to 800$^{\circ}C$ to investigate the effects of Mn- and K-addition on the catalytic activity of calcium oxide. To characterize the catalysts, X-ray powder diffraction(XRD), XPS, SEM, DSC, and TG analyses were performed. The catalytic reaction was carried out in a single-pass flow reactor using on-line gas chromatography system. Normalized reaction conditions were generally $p(CH_4)/p(O_2)=250$ Torr/50 Torr, total feed flow rate=30 mL/min, and 1 atm of total pressure with He being used as diluent gas. Among the catalysts tested, 6.3 mol% Mn-doped CaO catalyst showed the best $C_2$ yield of 8.0% with a selectivity of 43.2% at 775$^{\circ}C$. The $C_2$ selectivity increased on lightly doped CaO catalysts, while decreased on heavily doped CaO([Mn] > 6.3 mol%) catalysts. 6 wt.% Mn/CaO and 6 wt.% K/CaO catalysts showed the $C_2$ selectivities of 13.2% and 30.9%, respectively, for the reaction. Electrical conductivities of CaO and Mn-doped CaO were measured in the temperature range of 500 to 1000$^{\circ}C$ at Po2's of $10^{-3}\; to\;10^{-1}\;atm.$ The electrical conductivity was decreased with Mn-doping and increased with increasing $P0_2$in the range of $10^{-3}\;to\;10^{-1}\;atm,$ indicating the specimens to be p-type semiconductors. It was suggested that the interstitial oxygen ions formed near the surface can activate methane and the formation of interstitial oxygen ions was discussed on the basis of solid-state chemistry.

• Journal of Korean Society for Atmospheric Environment
• /
• v.29 no.6
• /
• pp.818-829
• /
• 2013

The collection of rainwater samples was made at Jeju area during 2009~2010, and the major ionic species were analyzed. In the comparison of ion balance, conductivity, and acid fraction for the validation of analytical data, the correlation coefficients showed a good linear relationship within the range of 0.966~0.990. The volume-weighted mean pH and electric conductivity were 4.9 and $17.8{\mu}S/cm$, respectively, at the Jeju area. The volume-weighted mean concentrations of ionic species in rainwater were in the order of $Cl^-$ > $Na^+$ > $nss-SO_4{^{2-}}$ > $NH_4{^+}$ > $NO_3{^-}$ > $Mg^{2+}$ > $H^+$ > $nss-Ca^{2+}$ > $HCOO^-$ > $K^+$ > $PO_4{^{3-}}$ > $CH_3COO^-$ > $NO_2{^-}$ > $F^-$ > $HCO_3{^-}$ > $CH_3SO_3{^-}$. The ionic strength of rainwater was $0.26{\pm}0.21$ mM during the study period. The composition ratios of ionic species were such as 50.1% for the marine sources ($Na^+$, $Mg^{2+}$, $Cl^-$), 30.9% for the anthropogenic sources ($NH_4{^+}$, $nss-SO_4{^{2-}}$, $NO_3{^-}$), and 4.7% for the soil source ($nss-Ca^{2+}$), and 3.1% for organic acids ($HCOO^-$, $CH_3COO^-$). From the seasonal comparison, the concentrations of $NO_3{^-}$, $nss-Ca^{2+}$, and $nss-SO_4{^{2-}}$ increased in winter and spring seasons, indicating a reasonable possibility of long range transport from Asia continent. Especially, the acidifying contributions by major inorganic acids ($nss-SO_4{^{2-}}$ and $NO_3{^-}$) and organic acids ($HCOO^-$ and $CH_3COO^-$) were 87.6% and 12.4%, respectively. In comparison by sectional inflow pathway of air mass during the rainy sampling days, the concentrations of $nss-SO_4{^{2-}}$ and $NO_3{^-}$ were relatively high when the air mass was moved from the China continent into Jeju area.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.24 no.2
• /
• pp.111-116
• /
• 1991

The effective p.eduction of 5'-GMP(5'-Guanylic acid) by enzymatic conversion of 5'-XMP(5'-Xanthyic acid) was investigated. The Iyophilized Brevibacterium ammoniagenes ATCC 19216 which were used as the XHP aminase source, was immobilized by entrapping in K-carrageenan, agar, polyacrylamide or Ca-alginate. $3\%$ K-carrageenan was selected as the most suitable matrix. In the production of 5'-GMP using the free cells of 3. ammoniagenes ATCC 19216, the optimum conditions were $42^{\circ}C$, PH 7.0, 100mg/ml glucose, 120mg/ml cell ,8mg/ml $MgSO_4\cdot7H_2O$, 5mg/ml POESA, 5mg/ml phytic acid. Under the conditions, $94.5\%$ of 5'-GMP was converted within 8 hours. In the production of 5'-GMP using the immobilized whole cells of B. ammoniagenes ATCC 19216, the optimum conditions were $37^{\circ}C$, pH 7.5, 50mg/ml glucose, 1mg/ml $KH_2PO_4$, 10mg/ml phytic acid, 60mg/ml cell, 8mg/ml $MgSO_4\;\cdot\;7H_2O$, 5mg/ml POESA. Under the conditions, $64.7\%$ of 5'-GMP was converted within 40 hours.

• Microbiology and Biotechnology Letters
• /
• v.16 no.4
• /
• pp.303-309
• /
• 1988

In order to establish the process of interspecific protoplast fusion of the genus Cellulomonas capable of utilizing of cellulose, C. flavigena NCIB 12901 and Cellulomonas sp. CSI-1, the optimum conditions for the regeneration and fusion were examined. The condition of suitable osmotic stabilizer for the protoplast regeneration of C. flavigena was established by using 0.4M sorbitol. And then, by addition of 3% po]yvinyl pyrrolidone (PVP) to cell wall regeneration medium, regeneration frequency was increased 3 times higher than that without PVP addition. The optimum conditions for the interspecific protoplast fusion between auxotrophic and antibiotics resistant mutants were obtained with 40%(W/V) of PEG (polyethylene glycol) 6000 as the fusogenic agent and 25mM of CaCl$_2$on treating time for 15 min. The fusion frequency between mutants was from 2.0$\times$10$^{-4}$ to 4.0$\times$10$^{-4}$ under the optimum conditions. The fusants were confirmed to revert from protoplast to cells of rod type during regeneration process and the aggregation of protoplast by PEG was observed. Also the progress of fusion was observed by scanning electron microscopy, Many isolated fusants were shown to be complement clones of both parents which occured at a high frequency among the isolated clones.

• The Korean Journal of Mycology
• /
• v.25 no.4 s.83
• /
• pp.369-376
• /
• 1997

These researches were carried out for improvement of medium for mycelial growth of Hericium erinaceus isolate KU-1. It grew well at pH 4 and $25^{\circ}C$. Glucose and sucrose were favorable carbon sources for mycelial growth. As nitrogen sources, ammonium acetate and arginine enhanced mycelial growth. Optimum C/N ratio was 200. Based On the results, the following recipe is suggested for synthetic medium for the mycelial growth: glucose 18.02 g, arginine 2.613 g, ammonium acetate 2.313 g, $CaCl_2\;0.33\;g$, $KH_2PO_4\;8.5\;g$, $MgSO_4{\cdot}7H_2O\;2.0\;g$, $FeSO_4{\cdot}7H_2O\;0.02\;g$, $ZnSO_4{cdot}7H_2O\;0.02\;g$, $MnSO_4{\cdot}7H_2O\;0.02\;g$, water 1 liter. This medium was superior for the mycelial growth to other conventional media such as Yeast malt extract agar (YMA), Park medium, Potato dextrose agar (PDA), Malt extract agar, Czapek-dox agar, Macaya-lizano medium and Yeast extract agar. This new synthetic medium is designated as Ko medium.

• Journal of Bio-Environment Control
• /
• v.15 no.1
• /
• pp.69-77
• /
• 2006

The experiment was conducted to investigate the nutrition absorption pattern in the growth stage and develope the optimal nutrient solution hydroponically grown the cherry tomato 'Koko' in closed substrate culture system with the nutrient solution of National Horticultural Research Station in Japan into 1/2S, 1S, and 2S. When plant was grown in 1/2S, the growth and yield were high and the pH and EC in the root zone were stable. Suitable composition of nutrient solution for cherry tomato was $NO_3-N\;6.8,\;PO_4-P\;2.7,\;K 3.2,\;Ca\;3.6\;and\;Mg\;1.1\;me\;L^{-1}$ in the early growth stage, $NO_3-N\;7.3,\;PO_4-P\;2.2,\;K\;3.7,\;Ca\;3.6;and\;Mg\;1.1\;me\;L^{-1}$ in the late growth stage by calculating a rate of nutrient and water uptake. To estimate the suitability for the nutrient solution in a development of cherry tomato developed by Wongkwang university in Korea (WU), plant was grown in perlite substrate supplied with different solution and strengths(S) by research station for greenhouse vegetable and floriculture in the Netherlands (Proefstation voor tuinbouw onder glas th Mssldwijk; PTG) of 1/2S, 1S, and 2S, respectively. The growth was good at the PTG and WU 2S in the early stage and the PTG of 1S and WU of 1S and 2S in the late stage. The highest yield of cherry tomato obtained in the WU of 2S. pH and EC in root zone of WU of 2S were stable during the early and late growth stage. Therefore when cherry tomato plant was grown in WU of 2S of EC $1.6{\sim}2.0\;dS\;m^{-1}$in the nutrient solution, not only stable growth and yield but also fertilizer reduction can be obtained than that of PTG.