• KSBB Journal
• /
• v.8 no.2
• /
• pp.156-163
• /
• 1993

Strains degrading ethylene glycol(EG) and terephthalic acid(TPA) were isolated from water systems, and identified as Pseudomonas sp. They were named as Pseudomonas sp. EAW for EG and as Pseudomonas sp. TS2 for TPA. The optimal culture conditions of temperature, pH and nitrogen source were found to be $35^{\circ}C$, 7.5 and ammonium sulfate, respectively. The growth of strains and removal efficiency was slightly promoted by trace elements such as niacin and biotin in case of EG, and by trace elements such as $Na_2MoO_4{\cdot}2H_2O$ and thiamin i case of TPA. With increasing inoculation sloe for batch culture, the removal efficiency of EG by the strain EAW was conspicuously increased, while the removal efficiency of TPA by the strain TS2 was not changed as much as that of EG. The growth rate of the strain EAW was much more decreased than that of the strain TS2 in the enrichment medium, as the frequency of repeated-batch culture in the rich-medium increased. in case of real wastewater, growth rate and removal efficiencies of EG and TPA were lower than those in the enrichment medium. $COD_{Mn}\;and\;COD_{Cr}$ removal efficiencies after 48 hrs batch culture in real wastewater were 89% and 93%, respectively. The specific growth rate was inhibited when the initial concentration of EG or TPA was more than 25g/L.

• Journal of the Korean Applied Science and Technology
• /
• v.32 no.4
• /
• pp.758-766
• /
• 2015

Dextran is a generic term for a bacterial exopolysaccharide synthesized from sucrose and composed of chains of D-glucose units connected by ${\alpha}$-1,6-linkages by using dextransucrases. Dextran could be used as vicosifying, stabilizing, emulsifying, gelling, bulking, dietary fiber, prebiotics, and water holding agents. We isolated new strain capable of producing dextran from Korean traditional kimchi and identified as Leuconostoc sp. strain JYY4. Batch fermentation was conducted in bioreactor with a working volume of 3 L. The media was MMY and 15% (w/v) sucrose. Mineral medium consisted of $3.0g\;KH_2PO_4$, $0.01g\;FeSO_4$, $H_2O$, $0.01g\;MnSO_4$, $4H_2O$, $0.2g\;MgSO_4\;7H_2O$, 0.01 g NaCl, $0.05g\;CaCl_2$ per 1 liter deionized water. The pH of media was initially adjusted to 6.0. The inoculation rate was 1.0% (v/v) of the working volume. Temperature was maintained at $28^{\circ}C$. The agitation rate was 100 rpm. The production pattern of dextran was associated with the cell growth. After 24 hr dextran reached its highest concentration of 59.4 g/L. The sucrose was consumed completely after 40 hr. Growth reached stationery phase when sucrose became limiting, regardless of the presence of fructose or mannitol. When the specific growth rate was 0.54 hr-1, utilization averaged 5.8 g/L-hr. The yield and productivity of dextran were 80% and 2.0 g/L-hr, respectively. Dextrans produced by were separated to two different size by an alcohol fraction method. The size of high molecular weight dextran (45% alcohol, v/v), less soluble dextran, was between MW 500,000 and 2,000,000. Soluble dextran (55% alcohol, v/v) was between 70,000 and 150,000. The molecular weight average of total dextran (70% alcohol, v/v) was between 150,000 to 500,000. The enzymatic hydrolyzates of total dextran of ATCC 13146 showed branched dextrans by Penicillium dextranase contained of glucose, isomaltose, isomaltotriose, and isomaltooligosaccharides greater than DP4 (degree of polymerization) that had branch points. Compounds greater than DP4 were branched isomaltooligosaacharides. Hydrolysates by the Lipomyces dextranase produced the same composition of oligosaccharides as those by Penicillin dextranase.

• Journal of Microbiology and Biotechnology
• /
• v.30 no.5
• /
• pp.668-680
• /
• 2020

Bacillus velezensis is an important plant growth-promoting rhizobacterium with immense potential in agriculture development. In the present study, Bacillus velezensis Lle-9 was isolated from the bulbs of Lilium leucanthum. The isolated strain showed antifungal activities against plant pathogens like Botryosphaeria dothidea, Fusarium oxysporum, Botrytis cinerea and Fusarium fujikuroi. The highest percentage of growth inhibition i.e., 68.56±2.35% was observed against Fusarium oxysporum followed by 63.12 ± 2.83%, 61.67 ± 3.39% and 55.82 ± 2.76% against Botrytis cinerea, Botryosphaeria dothidea, and Fusarium fujikuroi, respectively. The ethyl acetate fraction revealed a number of bioactive compounds and several were identified as antimicrobial agents such as diketopiperazines, cyclo-peptides, linear peptides, latrunculin A, 5α-hydroxy-6-ketocholesterol, (R)-S-lactoylglutathione, triamterene, rubiadin, moxifloxacin, 9-hydroxy-5Z,7E,11Z,14Z-eicosatetraenoic acid, D-erythro-C18-Sphingosine, citrinin, and 2-arachidonoyllysophosphatidylcholine. The presence of these antimicrobial compounds in the bacterial culture might have contributed to the antifungal activities of the isolated B. velezensis Lle-9. The strain showed plant growth-promoting traits such as production of organic acids, ACC deaminase, indole-3-acetic acid (IAA), siderophores, and nitrogen fixation and phosphate solubilization. IAA production was accelerated with application of exogenous tryptophan concentrations in the medium. Further, the lily plants upon inoculation with Lle-9 exhibited improved vegetative growth, more flowering shoots and longer roots than control plants under greenhouse condition. The isolated B. velezensis strain Lle-9 possessed broad-spectrum antifungal activities and multiple plant growth-promoting traits and thus may play an important role in promoting sustainable agriculture. This strain could be developed and applied in field experiments in order to promote plant growth and control disease pathogens.

• The Journal of Internal Korean Medicine
• /
• v.36 no.2
• /
• pp.165-179
• /
• 2015

Objectives: This experiment investigated the antimicrobial activity of Hwangryunheadok-tang and extracts of Scutellariae radix , Phellodendri cortex , Coptis rhizome , and Gardenia jasminoides against Salmonella typhimurium . Methods: After spreading S. typhimurium on a bacterial culture medium plate, antimicrobial activity was tested by dripping diluted Hwangryunheadok-tang or extracts of Scutellariae radix , Phellodendri cortex , Coptis rhizome , or Gardenia jasminoides (80 μl, diluted 100, 50, 10, and 1%) onto the plate, followed by culture for 16 to 72 hours. The minimal inhibitory concentration (MIC) was tested by dripping the minimum dilution that showed antimicrobial activity (80, 60, 40, and 20 μl) and measuring the density. The antimicrobial activity of Hwangryunheadok-tang and four extracts showed continuous antibacterial activity against S. typhimurium throughout the experiment. Result: 1. S. typhimurium . (Standard Microorganism, ATCC) 1) The Hwangryunheadok-tang and extracts of Scutellariae radix , Phellodendri cortex , and Coptis rhizome showed antibacterial activity in the undiluted solutions and in 50% dilutions. Gardenia jasminoides extract showed potency only in the undiluted solution. The antimicrobial potency of the undiluted solution was increased when the volume of inoculation was increased, but no difference was noted when the culture time was extended. All the extracts showed antimicrobial potency against S. typhimurium . 2. S. typhimurium isolated from diarrhea patients 1) When compared to the standard microorganism experiment on S. typhimurium , the MICs of the five extracts were increased. However, whereas the antimicrobial potency of doxycycline was lost entirely against bacteria isolated from patients with diarrhea, the antimicrobial potency of all the extracts was diminished but did not disappear. 2) The antimicrobial activity of Hwangryunheadok-tang and four extracts was continuous even when the culture time was extended to 16, 24, and 72 hours. Conclusions: The Hwangryunheadok-tang and four kinds of extracts have antimicrobial activity against S. typhimurium . Comparison of a standard microorganism with S. typhimurium isolated from diarrhea patients showed that the antimicrobial activity of all the extracts was better than that of antibiotics. Further studies should focus on the value and benefits of Hwangryunheadok-tang , and the four kinds of extracts as clinical treatments.

• Journal of fish pathology
• /
• v.22 no.3
• /
• pp.253-262
• /
• 2009

We conducted bacteriological and histopathological analysis for olive flounder Paralichthys olivaceus after experimental infection with Streptococcus parauberis (FP2284) isolated from diseased olive flounder under different stress conditions. Experimental challenge was performed in healthy flounder (40.4 g in average body weight) by intraperitoneal (i.p.) injection with $2{\times}10^{8}$ CFU/fish under normal (no stress) or netting (for 2 min, twice/day) stress condition. The cumulative mortalities of no-stress and netting stress group were 70% and 95%, respectively. The most prevalent changes observed in experimentally infected flounder were darkness of skin and inflammation of the heart. Severe pericarditis, myocarditis and fibrosis were observed in the heart of the affected flounder. The results of viable counts showed the number of bacteria of the heart tissue was maintained over the $10^{4}$ CFU $g^{-1}$ heart for 3 weeks after inoculation. Histological lesions of the heart was more extensive and gradual decrease in bacterial numbers of heart tissue was delayed under stress condition.

• Research in Plant Disease
• /
• v.11 no.2
• /
• pp.193-197
• /
• 2005

The effect of pH on the survival of R. solanacearum and its transmission via roots of tomato in hydroponic culture were studied in laboratory and greenhouse. In laboratory experiment, R. solanacearum could not survive for 24h in nutrient solution with pH of $4{\cdot}0;or\;4{\cdot}5$, while 1, 14, 51 and $62\%$ of inoculum survived at pH $5{\cdot}0,\;5{\cdot}6\;and\;6{\cdot}5$, respectively. When tomato plants were inoculated with R. solanacearum through wounds on the stems, the bacteria moved downward from the inoculation site to the roots and infectious bacteria were released from the roots into the nutrient solution. Of two pH regimes tested in greenhouse nutrient-film technique(NFT) culture, the R. solanacearum population was significantly lower in pH 5.0 than in pH 6.5 in most sampling data. In treatments in which R. solanacearum was introduced by transplanting two root-inoculated plants, significantly move plants developed wilt at pH $6{\cdot}5$(34 out of 48 plants) than at pH 5.0(11 out of 48 plants). In addition, when the bacterium was introduced by transplanting two stem-inoculated plants at pH $6{\cdot}5$, seven out of 24 plants developed wilt.

• Journal of Mushroom
• /
• v.11 no.2
• /
• pp.53-62
• /
• 2013

A total of 35 phosphate solubilizing bacterial strains were isolated from waste mushroom bed of Agaricus bisporus in Buyeo-Gun, Chungnam and screened for the production of indole acetic acid (IAA). The best IAA producing strain was identified as Pantoea rodasii using 16S rRNA analysis. In addition to the IAA production, this strain could act as an efficient phosphate solubilizer (1100 ${\mu}g$ $ml^{-1}$ after 5 days of incubation) also. The selected strain was cultured under different conditions in order to assess the optimum conditions for maximum IAA production. The nutrient broth (NB) medium was recorded as the best medium, where the maximum IAA production (229 ${\mu}g$ $ml^{-1}$) was recorded at the start of stationary phase (12 hours after inoculation) of the bacteria growth. The performance of the strain was found to be maximum at the temperature of $30^{\circ}C$ followed by $25^{\circ}C$. IAA production was found to be increased with increasing tryptophan concentration (from 0.1 to 0.6%), however beyond this limit, a slight reduction in IAA production was observed. The strains' ability to produce IAA was further confirmed by extraction of crude IAA and subsequent TLC analysis. A specific spot from the extracted IAA preparation was found corresponding with the standard spot of IAA with same $R_f$ value. The results of HPLC analysis conducted in identifying and quantifying the IAA production more precisely, are in agreement with the results of the assessment done with colorimetric method. As revealed by the results of the pot experiment, the isolated strain could significantly enhance the growth (as measured by shoot and root growth) of mung bean plants compared to that of non-inoculated plants. Therefore it can be concluded that the present strain, Pantoea rodasii has great potential to be used as bio-inoculants.

• Asian-Australasian Journal of Animal Sciences
• /
• v.30 no.7
• /
• pp.950-956
• /
• 2017

Objective: Effects of newly isolated Lactobacillus plantarum on the fermentation and chemical composition of fresh rice straw silage was evaluated in this study. Methods: Lactic acid bacteria (LAB) from good crop silage were screened by growing them in MRS broth and a minimal medium with low carbohydrate content. Selected LAB (LAB 1821) were Gram-positive, rods, catalase negative, and were identified to be Lactobacillus plantarum based on their biochemical characteristics and a 16S rRNA analysis. Fresh rice straw was ensiled with two isolated LAB (1821 and 1841), two commercial inoculants (HM/F and P1132) and no additive as a control. Results: After 2 months of storage at ambient temperature, rice straw silages treated with additives were well-preserved, the pH values and butyric and acetic acid contents were lower, and the lactic acid content and lactic/acetic acid ratio were higher than those in the control (p<0.05). Acidity (pH) was lowest, and lactic acid highest, in 1821-treated silage (p<0.05). The $NH_3-N$ content decreased significantly in inoculant-treated silage (p<0.05) and the $NH_3-N$ content in 1821-treated silage was lowest among the treatments. The dry matter (DM) content of the control silage was lower than that of fresh rice straw (p<0.05), while that of the 1841- and p1174-inoculant-treated silages was significantly higher than that of HM/F-treated silage. Microbial additives did not have any significant (p>0.05) effect on acid detergent fiber or neutral detergent fiber contents. Crude protein (CP) content and in vitro DM digestibility (IVDMD) increased after inoculation of LAB 1821 (p<0.05). Conclusion: LAB 1821 increased the CP, IVDMD, lactic acid content and ratio of lactic acid to acetic acid in rice straw silage and decreased the pH, acetic acid, $NH_3-N$, and butyric acid contents. Therefore, adding LAB 1821 improved the fermentation quality and feed value of rice straw silage.

• Korean Journal of Food Science and Technology
• /
• v.46 no.4
• /
• pp.438-445
• /
• 2014

We examined biogenic amine (BA) production as well as the diversity of bacterial flora in 11 types of commercial makgeolli stored at 4 and $20^{\circ}C$. Moreover, we studied the BA-producing activity of three L. plantarum strains isolated from makgeolli. At $20^{\circ}C$, the BA content was highly increased and the denatured DNA bands were more variable in non-sterilized makgeolli compared to sterilized makgeolli. The major BAs produced in commercial makgeolli were histamine and putrescine. Histamine, tyramine, putrescine, and cadaverine were produced in excess by inoculation of the three L. plantarum isolates to makgeolli stored at $20^{\circ}C$ for 21 days. These results suggest that some L. plantarum strains in makgeolli can produce different types of BAs, depending on the extent of degradation of makgeolli.

• Korean Journal of Plant Tissue Culture
• /
• v.28 no.4
• /
• pp.221-225
• /
• 2001

Some factors of wounding methods, solidifying agents, origin of leaf explants, cone. of acetosyring-one, and MES affecting regeneration and transformation by Agrobacterium tumefaciens were investigated to establish an efficient transformation system of apple. Wounding by cutting the leaves merely showed the tendency of regeneration and transformation with higher efficiency compared with that of wounding by non-traumatic forcep when carrying out co-cultivation for three days after bacterial inoculation. While examining the solidifying agents of medium with the combination of agar (A)＋Gelrit $e^{ }$ (G) in g. $L^{-1}$ , the higher concentration of Gelrit $e^{ }$ increased the efficiency of regeneration. However, there was no difference in the efficiency of transformation from the treatments of 2.5 G, 3.5 A+1.2 G, and 7.0 G. The origin of leaf explants showed no difference statistically in the efficiency of regeneration and transformation, but that from the shoots of proliferation medium showed the tendency with higher efficiency. The concentration of above 0.1 mM acetosyringon had an increase in the efficiency of regeneration and transformation and the concentration of 0.15 mM had the highest efficiency of transformation in the treatment of acetosyringone with different concentration. There was no effect of MES on regeneration and transformation.ion.