• Journal of the Korea Organic Resources Recycling Association
• /
• v.26 no.2
• /
• pp.11-18
• /
• 2018

Biochar is a carbon-rich solid product obtained by the pyrolysis of biomass. It has been suggested to mitigate climate change through increased carbon storage and reduction of greenhouse gas emission. The objective of this study was to evaluate carbon dioxide ($CO_2$) and nitrous oxide ($N_2O$) emissions from soil after various biochars addition. The biochars were produced by pyrolysing pear branch, rice hull and bean straw at $400{\sim}500^{\circ}C$. The treatments were consisted of a control without input of biochar and three type biochars input as 5.0 Mg/ha. Emissions of $CO_2$ and $N_2O$ from upland soil were determined using closed chamber for 8 weeks at $25^{\circ}C$ of incubation temperature. It was shown that the cumulative $CO_2$ were 207.1 to $255.2g\;CO_2/m^2$ for biochar input treatments and $258.6g\;CO_2/m^2$ for the control after experimental periods. The cumulative $CO_2$ emission was slightly decreased in biochar input treatment compared to the control. It was appeared that cumulative $N_2O$ emissions were $2,890.6mg\;N_2O/m^2$ for control, 379.7 to $525.2mg\;N_2O/m^2$ for biochar input treatment at the end of experiment. All biochar treatments were found to significantly reduce $N_2O$ emission by 82~87%. Consequently the biochar from byproducts such as pear branch, rice hull and bean straw could suppress the soil $N_2O$ emission. The results from the study imply that biochar can be utilized to reduce greenhouse gas emission from the upland field.

• Journal of Science Education
• /
• v.33 no.2
• /
• pp.336-345
• /
• 2009

The purpose of this study is to analysis ERF components patterns of causal questions generated during the observation of biological phenomenon. First, the system that shows pictures causing causal questions based on biological phenomenon (evoked picture system) was developed in a way of cognitive psychology. The ERF patterns of causal questions based on time-series brain processing was observed using MEG. The evoked picture system was developed by R&D method consisting of scientific education experts and researchers. Tasks were classified into animal (A), microbe (M), and plant (P) tasks according to biological species and into interaction (I), all (A), and part (P) based on the interaction between different species. According to the collaboration with MEG team in the hospital of Seoul National University, the paradigm of MEG task was developed. MEG data about the generation of scientific questions in 5 female graduate student were collected. For examining the unique characteristic of causal question, MEG ERF components were analyzed. As a result, total 100 pictures were produced by evoked picture and 4 ERF components, M1(100~130ms), M2(220~280ms), M3(320~390ms), M4(460~520ms). The present study could guide personalized teaching-learning method through the application and development of scientific question learning program.

• Journal of Life Science
• /
• v.18 no.10
• /
• pp.1426-1434
• /
• 2008

This study was conducted to investigate the effects of supplementation of synbiotics manufactured with anaerobic bacteria, yeast and mold on preservation of total mixed ration (TMR) by exposing days. Eight treatments were composed of untreated synbiotics(US), bacterial synbiotics (BS), yeasty synbiotics (YS), moldy synbiotics (MS), bacterial and mouldy synbiotics (BMS), yeasty and moldy synbiotics (YMS), bacterial and yeasty synbiotics (BYS), and bacterial, yeasty and moldy synbiotics (BYMS). After 7 days of anaerobic fermentation, fermented-TMRs were exposed to the air during 1, 3, 5, 7, 14 and 21 days. One hundred forty four (8 treatments${\times}$6 days${\times}$3 replications) fermented-TMRs were manufactured by vinyl bag ($43\;cm{\times}58\;cm$). Although no significant differences in the activities of carboxymethylcellulase, xylanase and amylase were observed among treatments, theirs acivities were seemed to increase by treatment of BYS or YMS containing yeast. Total bacterial and mold counts also decreased in the treatments containing yeast. Potential pathogenic bacteria were less detected in BYS and BMYS for E. coli, BMYS and YS for Salmonella, and BMS and BMYS for Shigella than those of the other treatments, MS was, however, contaminated easier than US by pathogenic bacteria. From above results, synbiotics containing facultative anaerobic yeast have effects for preservation of TMR fermented anaerobically. Particularly, BMYS treatment having good results in nutrient contents, dry matter loss and pathogenic bacteria amounts was a resonable synbiotics for preservation of the fermented-TMR.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.34 no.5
• /
• pp.545-549
• /
• 2001

To develop a natural antibacterial agent for fish bacterial diseases, antibacterial activity, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and bactericidal effect of cinnamon bark extract were examined against fish pathogenic bacteria. The antimicrobial effect of the extract to the fish diet was also estimated, Cinnamon bark extract showed the broad spectrum of antibacterial activity against fish pathogenic bacteria, especially, it had strong activity against Streptococcus iniae, Edwardsiella tarda and Listonella anguillarum. Its MIC was $75.8\sim189.6{\mu}g/mL$ against Cram positive bacteria, and $75.8\sim113.8{\mu}g/mL$ against Gram negative bacteria in liquid medium, It was found to show stronger bactericidal action against Gram negative bacteria than Cram positive bacteria. According to increasing concentrations of the extract, it resulted in a proportional reduction of viable cell counts of both S. iniae and L. anguillarum. The former was not detected by addition of $189.6{\mu}g/mL$ after 12 hours incubation and the latter by addition of $151.6{\mu}g/mL$ after 24 hours incubation, respectively. It was reasonable that fish diet was soaked in cinnamon bark extract for ten minutes. The relationship formula between the weight of fish diet and the extract absorbed to fish diet was Y=7.2726X+4.5083 ($R^2=0.9998$). The fish diet soaked in the extract inhibited the growth of all strains used in this study. Its antibacterial activity was stable at the range from $10^{\circ}C\;to\;35^{\circ}C$ during the storage period of 28 days. When the diet soaked in the extract was incubated in liquid medium at $35^{\circ}C$, it inhibited the growth of microorganisms inhabited in the diet.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.6
• /
• pp.1114-1119
• /
• 2012

This study was conducted to assess the microbial toxicity of ionic silver solution ($Ag^+N$) and silver nanoparticle suspension ($Ag^0NP$) based on the Microtox bioassay. In this test, the light inhibition of luminescent bacteria was measured after 15 and 30 min exposure to aqueous solutions and soils spiked with a dilution series of $Ag^+N$ and $Ag^0NP$. The resulting dose-response curves were used to derive effective concentration (EC25, $EC_{50}$, EC75) and effective dose ($ED_{25}$, $ED_{50}$, $ED_{75}$) that caused a 25, 50 and 75% inhibition of luminescence. In aqueous solutions, $EC_{50}$ value of $Ag^+N$ after 15 min exposure was determined to be < $2mg\;L^{-1}$ and remarkably lower than $EC_{50}$ value of $Ag^0NP$ with $251mg\;L^{-1}$. This revealed that $Ag^+N$ was more toxic to luminescent bacteria than $Ag^0NP$. In soil extracts, however, $ED_{50}$ value of $Ag^+N$ with 196 mg kg-1 was higher than $ED_{50}$ value of $Ag^0NP$ with $104mg\;kg^{-1}$, indicating less toxicity of $Ag^+N$ in soils. The reduced toxicity of $Ag^+N$ in soils can be attributed to a partial adsorption of ionic $Ag^+$ on soil colloids and humic acid as well as a partial formation of insoluble AgCl with NaCl of Microtox diluent. This resulted in lower concentration of active Ag in soil extracts obtained after 1 hour shaking with $Ag^+N$ than that spiked with $Ag^0NP$. With longer exposure time, EC and ED values of both $Ag^+N$ and $Ag^0NP$ decreased, so their toxicity increased. The toxic characteristics of silver nanomaterials were different depending on existing form of Ag ($Ag^+$, $Ag^0$), reaction medium (aqueous solution, soil), and exposure time.

• Journal of Animal Science and Technology
• /
• v.50 no.1
• /
• pp.99-110
• /
• 2008

This study was conducted to determine the effect of pH adjustment and the addition of cryoprotectants on the storage properties of chicken breast surimi. Surimi as a control was prepared with Alaska pollack by two times of washing treatment and addition of cryoprotectants(4% sugar, 5% sorbitol and 0.3% polyphosphate). Three types of surimi were manufactured by different cryoprotectant conditions(T1: 5% sorbitol+0.3% polyphosphate, T2: 4% sugar+5% sorbitol+0.3% polyphosphate, T3: 2% salt+4% sugar+5% sorbitol+0.3% polyphosphate) and frozen after adjusting the surimi to pH 11.0. The amino acid and saturated fatty acid composition were significantly higher in the control. EAA(essential amino acid), FAA(amino acid in relation to flavor), SAAA(amino acid in relation to saccarinity) and FRAA (fragrant amino acid) were significantly higher in the control. The TBARS(thiobarbituric acid reactive substances) and VBN(volatile basic nitrogen) were increased with storage times. TBARS and VBN values were significantly higher in the control and T3 than the other treatments. The VBN was significantly higher in control and T3 than other surimi samples. Chicken breast surimi adjusted to pH 11.0 had higher in microorganisms than the control, and T1 sample had the highest total plate count. Sensory evaluations were significantly higher in the control and T3 than the other samples. Especially, the overall acceptability of T3 was similar to the control.

• Korean Journal of Food Science and Technology
• /
• v.10 no.2
• /
• pp.237-244
• /
• 1978

Among the strains isolated form the various sources, the strain AC-12 producing a powerful pectinase was selected by the extensive screening test. The selected strain was indentified and its toxicity investigated. The conditions of the pectinase production, the characteristics of the purified enzyme and the clarification effect on the apple juice were studied. 1. The selected strain AC-12 was identified by the classification method of paper and fennel and named as Aspergillus sp. AC-12. 2. As a result of the breeding test of the white mouse, no toxicity was found from this enzyme. 3. The yield of pectinase in the medium of defatted rice bran was much better than that in the medium of wheat bran. 4. The optimum conditions for the culture of the strain in the medium of defatted rice bran were that the cultural time was 72hrs, the amount of water to be added about 80%, temperature $30{\sim}35^{\circ}C$ and pH $3.0{\sim}5.0$. 5. The yield of pectinase was slightly increased by the addition of pectin to the medium of defatted rice bran and by the addition of pectin, $NaNO_3$ and $K_2HPO_4$ to the medium of wheat bran, respectively. 6. The optimum conditions for the enzyme activity were pH $3.0{\sim}4.0$ and temperature $40{\sim}50^{\circ}C$. The enzyme was stable below $40^{\circ}C$ and pH $2.0{\sim}8.0$, respectively. But above $50^{\circ}C,$ this enzyme was abruptly inactivated. The activity was slightly increased by the addition of $MnSO_4\;and\;CuSO_4.$ 7. It was regarded that the opimum temperature for the clarification of the apple juice was $40{\sim}50^{\circ}C$, the optimum pH 3.0 and the optimun concentration of the enzyme 0.1%, and the apple juice was almost clarified by the reaction at $45^{\circ}C$ for 60 minutes.

• Applied Biological Chemistry
• /
• v.26 no.4
• /
• pp.222-230
• /
• 1983

This study was designed to develop a process for the immobilization of xylose isomerase(D-xylose ketol isomerase, EC 5.3.1.5) from Streptomyces griseolus previously isolated by the authors and its application on a pilot plant scale for the production of high fructose corn syrup. The biomass which has endo-excreted xylose isomerase was homogenized under a pressure of $500kg/cm^2$ and 90.8% of the enzyme recovery of the native activity was obtained as compared to 54.7% recovery by the lysozyme treatment. Ionic bonding method was adopted for the enzyme immobilization due to its many reported merits. It was found that the porous resins such as Diaion HP 20, Duolite A-7, Amberlite IRA 93 and 94 were effective in immobilizing the enzyme. In addition, it was disclosed that the regeneration form of $BO_4--$ is effective for Amberlite IRA 93 and $HCO_3-$ for Diaion HP 20. Optimal immobilization condition for Amberlite IRA 93 was pH 8.0 and $55^{\circ}C$ yielding 80.6% of immobilization. Activity decay test showed half life of the immobilized enzyme with Amberlite IRA 93 was more than 24 days at $65^{\circ}C$. The carrier was evaluated to be resuable and its result showed the relative immobilization yields were 98.2, 93.3, 90.7 and 87.5%, respectively at second, third, forth and fifth rebinding test of the enzyme on Amberlite IRA 93. Optimal temperature of the immobilized enzyme was slightly lowered and the range widened to $60\sim70^{\circ}C$, while optimal pH moved toward $8.0\sim8.3$ in its isomerization reaction. The trial production result of high fructose corn syrup in pilot scale immobilization showed that one liter of immobilized xylose isomerase (350 IXIU/ml-R) is capable producing about 293l high fructose corn syrup(75% dry substance) in 30 days.

• Korean Journal of Soil Science and Fertilizer
• /
• v.24 no.1
• /
• pp.69-76
• /
• 1991

A pot experiment was conducted to find out the effects of lime and phosphate application on the changes of number of soil microorganisms, indigenous Rhizobium japonicum, nodule formation, and ureide-and amide-N in leaf and stem exudate of soybean plant under uncultivated hillside red earth in very low pH value, organic matter, available phosphate, and cation exchange capacity. The results obtained were summarized as follows : 1. The plant height, stem length, root dry weight and nodule weight were significantly increased with the application of lime and phosphate application than that of control plot. 2. The concentration of amide-N in soybean plant at the 45 days after sowing was obtained as high in order of control>lime> lime+phosphate while the concentration was obtained in order of Iime+phosphate>lime> control at flowering stage 3. However, concentration of ureide-N in the soybean leaf at the 45 days after sowing was obtained as high in order of control>lime>lime+hosphate while reversed concentration was obtained in stem. 4. The number of soil microorgan isms were increased with increase of pH value, available phosphate and soil exchangeable cation. 5. Significantly negative high correlation were obtained with the concentration of Al, Fe in soil and the concentration of amide-and ureide-N in soybean plant at flowering stage while positive correlation was obtained with plant growth and the concentration of ureide-N.

• Journal of Life Science
• /
• v.20 no.9
• /
• pp.1373-1377
• /
• 2010

Coastal sand-dune plants can survive very effectively with the help of various microbes, especially ecto- and endomycorrihizae. Penicillium citrinum KACC43900 was screened according to growth promoting activity on sand-dune plants Calystegia soldanella and Ischaemum anthephoroides. In this study, coastal sand-dune plants were treated with a fungal culture filtrate of endophytic fungus P. citrinum KACC43900 to confirm the promotion of plant growth. C. soldanella and I. anthephoroides were used as representative coastal sand-dune plants, and their shoot length, plant length, and dry weight were analyzed. The shoot lengths of control C. soldanella and I. anthephoroides were 8.60 cm and 8.12 cm, and those of samples treated with fungal culture filtrates of C. soldanella and I. anthephoroides for 20 days were 16.30 cm and 10.56 cm, respectively. The plant lengths of control C. soldanella and I. anthephoroides were 14.90 cm and 14.80 cm, and those of samples treated with fungal culture filtrates of C. soldanella and I. anthephoroides for 20 days were 24.06 cm and 17.06 cm, respectively. The dry weight of C. soldanella and I. anthephoroides treated with fungal culture filtrates of C. soldanella and I. anthephoroides for 20 days were 0.163 g and 0.032 g, respectively. It was shown that the growth of shoots in C. soldanella and I. anthephoroides was promoted, 89.54% and 29.60%, by culture filtrate of P. citrinum KACC43900.