• Journal of Marine Bioscience and Biotechnology
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• v.9 no.1
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• pp.14-21
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• 2017

The purpose of this study was to inhibit biofouling on a selectively permeable membrane (SPM) and increase biomass productivity in marine photobioreactors (PBRs) for microalgal cultivation by chemical treatment. Surfaces of a SPM, composed of polyethylene terephthalate (PET), was sulfonated to decrease hydrophobicity through attaching negatively charged sulfonic groups. Reaction time of sulfonation was varied from 0 min to 60 min. As the reaction time increased, the water contact angle value of SPM surface was decreased from $75.5^{\circ}$ to $44.5^{\circ}$, indicating decrease of surface hydrophobicity. Furthermore, the water permeability of sulfonated SPM was increased from $5.42mL/m^2/s$ to $10.58mL/m^2/s$, which reflects higher nutrients transfer rates through the membranes, due to decreased hydrophobicity. When cultivating Tetraselmis sp. using 100-mL floating PBRs with sulfonated SPMs, biomass productivity was improved by 34% compared with the control group (non-reacted SPMs). In addition, scanning electron microscopic observation of SPMs used for cultivation clearly revealed lower degree of cell attachment on the sulfonated SPMs. These results suggest that sulfornation of a PET SPM could improve microalgal biomass productivity by increasing nutrients transfer rates and inhibiting biofouling by algal cells.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1135-1142
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• 2003

The purification and characteristics of the biosynthesis enzyme of vitamin C from microorganisms related with kimchi fermentation were investigated to define vitamin C biosynthetic pathways in yeast. A yeast strain (Pichia onychis 16-4) which synthesizes vitamin C with galacturonic acid as substrate at high rate was isolated from kimchi. The enzyme $L-galactono-{\gamma}-lactone$ oxidase isolated from the yeast was purified and characterized. The specific activity of the crude enzyme was 7.26 unit/mg protein, which increased to 4,698 unit/mg protein with a chromatography of Sephacryl S-200HR; indicating a 647.1-fold level of purification. The molecular weights of the dissociated enzymes were estimated to be 31,000, 39,000, and 50,000 KD. Among the substrates tested, $L-galactono-{\gamma}-lactone$ was the most effective. The enzyme showed optimum activity ah pH 7.8 and 35c. The purified enzyme uses $O_2$ as the electron acceptor for oxidation of $L-galactono-{\gamma}-lactone$.

• Journal of the Optical Society of Korea
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• v.19 no.6
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• pp.705-710
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• 2015

The fabrication process of thin boron-doped nanocrystalline diamond (B-NCD) microelectrodes on fused silica single mode optical fiber cladding has been investigated. The B-NCD films were deposited on the fibers using Microwave Plasma Assisted Chemical Vapor Deposition (MW PA CVD) at glass substrate temperature of 475 ℃. We have obtained homogenous, continuous and polycrystalline surface morphology with high sp³ content in B-NCD films and mean grain size in the range of 100-250 nm. The films deposited on the glass reference samples exhibit high refractive index (n=2.05 at λ=550 nm) and low extinction coefficient. Furthermore, cyclic voltammograms (CV) were recorded to determine the electrochemical window and reaction reversibility at the B-NCD fiber-based electrode. CV measurements in aqueous media consisting of 5 mM K₃[Fe(CN)₆] in 0.5 M Na₂SO₄ demonstrated a width of the electrochemical window up to 1.03 V and relatively fast kinetics expressed by a redox peak splitting below 500 mV. Moreover, thanks to high-n B-NCD overlay, the coated fibers can be also used for enhancing the sensitivity of long-period gratings (LPGs) induced in the fiber. The LPG is capable of measuring variations in refractive index of the surrounding liquid by tracing the shift in resonance appearing in the transmitted spectrum. Possible combined CV and LPG-based measurements are discussed in this work.

• Journal of Microbiology and Biotechnology
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• v.23 no.7
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• pp.905-912
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• 2013

A novel species, Metschnikowia cibodasensis, is proposed to accommodate eight strains (ID03-$0093^T$, ID03-0094, ID03-0095, ID03-0096, ID03-0097, ID03-0098, ID03-0099, and ID03-0109) isolated from flowers of Saurauia pendula, Berberis nepalensis, and Brunfelsia americana in Cibodas Botanical Garden, West Java, Indonesia. The type strain of M. cibodasensis is ID03-$0093^T$ (= NBRC $101693^T$ =UICC $Y-335^T$ = BTCC-$Y25^T$). The common features of M. cibodasensis are a spherical to ellipsoidopedunculate shaped ascus, which contains one or two needle-shaped ascospores, and lyse at maturity. Asci generally develop directly from vegetative cells but sometimes from chlamydospores. The neighbor-joining tree based on the D1/D2 domain of nuclear large subunit (nLSU) ribosomal DNA sequences strongly supports that M. cibodasensis (eight strains) and its closest teleomorphic species, M. reukaufii, are different species by a 100% bootstrap value. The type strain of M. cibodasensis, ID03-$0093^T$, differed from M. reukaufii NBRC $1679^T$ by six nt (five substitutions and one deletion) in their D1/D2 region of nLSU rDNA, and by 18 nt (five deletions, four insertions, and nine substitutions) in their internal transcribed spacer regions of rDNA, respectively. Four strains representative of M. cibodasensis (ID03-$0093^T$, ID03-0095, ID03-0096, and ID03-0099) showed a mol% G+C content of $44.05{\pm}0.25%$, whereas that of M. reukaufii NBRC $1679^T$ was 41.3%. The low value of DNA-DNA homology (5-16%) in four strains of M. cibodasensis and M. reukaufii NBRC $1679^T$ strongly supported that these strains represent a distinct species.

• Journal of Plant Biotechnology
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• v.49 no.4
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• pp.356-361
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• 2022

Bacillus sp. is a useful strain for agriculture because it promotes plant growth and controls plant pathogens through a variety of mechanisms. In this study, we obtained a microbial preparation with a high number of viable cells by culturing newly isolated soil bacteria on an optimized medium. Subsequently, we applied this preparation to lettuce to enhance its growth and yield. First, B. amyloliquefaciens ISP-5 was isolated from soil. Next, optimization of culture medium was carried out using 5 L scale fermenters. When culturing B. amyloliquefaciens ISP-5 on this optimized medium, the number of viable cells was approximately 1000 times higher than that obtained from culturing on the commercial medium. Afterwards, the plant growth promotion properties of the ISP-5 strain were evaluated using lettuce as a test plant. Foliar spray treatment of lettuce was carried out by inoculating half the standard concentration suspension (0.5 × 10⁷ cfu/ml). As a result, leaf width increased by 8.6% and leaf length increased by 12.9% compared to the control group. Live weight also increased by 24.2% and dry weight by 23.9%. Considering the results from field test, B. amyloliquefaciens ISP-5 showed potential as a plant growth-promoting bacteria.

• Journal of Environmental Impact Assessment
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• v.28 no.6
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• pp.604-615
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• 2019

In this study, we produce a new type of the algae soil conditioner(ASC) using discarded algae biomass through a composting process and evaluate its nutritional characteristics. As the main ingredient, the ASCs used algae biomass collected through the coagulation-floating method and made by adding a variety of additional supporting materials (sawdust, pearlite, oilcake etc.). ASCs were divided into 0% in blank, 11.7% in ASC1, 21.6% in ASC2, 37.6% in ASC3, 59.5% in ASC4, and composted during 127 days. ASCs showed a sharp increase in temperature by aerobic microbial reaction, and 6~7 high and low temperature peaks were observed. As a result of physicochemical analysis, mineralization proceeded according to decomposing the organic matter and there was a marked increase not only in macronutrients (TN, P₂O₅, K₂O), but also in secondary macronutrients (CaO, MgO). The microbial community change was found in stage 1 (bacteria, filamentous fungi) → stage 2 (actinomycetes, bacteria) → stage 3 (Bacillus sp.), depending on the maturation process. It was estimated that microbial transition was closely related to temperature change and nutritional behavior. The quality of soil conditioner can be determined according to the maturity of compost process, and it was determined that effective microbial activity could be induced by controlling algae biomass below 59.5% in this study. In conclusion, we found out the possibility of manufacturing and utilizing soil conditioner recycled algae biomass and if further technological development is made on the basis it can be used as an effective soil conditioner.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.2
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• pp.155-168
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• 1986

In Korea, lots of Israeli carp (Cyprinus carpio) are cultured by means of net cages in dams and lakes, but many carp have been subjected to heavy infestation of the cestoid, Bothriocephalus opsariichthydis. Nevertheless the parasitic state and life history of the cestoid are not yet reported. This reason led the author to study the parasitic state and life history of B. opsariichthydis parasitized in the carp in order to take effective control measures against its damage. Israeli carp were sampled from two fish farms, in Taech'on and Kyongch'on. After dissection of the specimens, the cestoid were obtained and the parasitic rates were examined. After taking the eggs from adult worms, the development of the eggs were observed. Coracidia were exposed to four kinds of crustaceans in order to investigate the infection rate and development of the larva. Finally, tile development of the larva in the final host was investigated. The fully mature eggs were in the cleavage stage, when they are released, and the size ranged 47.5 to 55.0 $(50.9){\times}30.0$ to 32.5 (31.1) um, in the state of under-developed coracidia and blastomeres. The parasitic rate of the cestoid in Israeli carp from Taechon was $55.5\%$ in 1984 and $21.6\%$ in 1985, that from Kyongchon was $64.7\%$ in 1984, and color carp from Kusan was $14.9\%$ in 1984. The eggs were hatched to coracidia within 48 hours under 26 to $28^{\circ}C$. The cestoid showed a strong affinity to Thermocyclops hyalinus and Paracyclops fimbriatus and the infection rates were $93.5\%$ and $75.5\%$, respectively. At 14 days after the infection to Thermocyclops hyalinus and Paracyclops fimbriatus, the larvae of the cestoid grew into fully developed procercoids; 207 to $226 (214){\times}90$ to 102 (94) um in size. Sixty days after carp have ingested the Thermocyclops hyalinus infected with the fully developed procercoids, the larvae of the cestoid matured into adult worms in the intestines of the carp.

• Korean Chemical Engineering Research
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• v.47 no.2
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• pp.220-229
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• 2009

Strain improvement and morphology investigation in bioreactor cultures were undertaken in suspended cultures of Phellinus linteus mycelia for mass production of protein-bound polysaccharides(soluble ${\beta}$-D-glucan), a powerful immuno-stimulating agent. Phellineus sp. screened for this research was identified as Phellinus linteues through ITS rDNA sequencing method and blast search, demonstrating 99.7% similarity to other Phellinus linteus strains. Intensive strain improvement program was carried out by obtaining large amounts of protoplasts for the isolation of single cell colonies. Rapid and large screening of high-yielding producers was possible because large numbers of protoplasts ($1{\times}10^5{\sim}10^6\;protoplasts/ml$) formed using the banding filtration method with the cell wall-disrupting enzymes could be regenerated in relatively high regeneration frequency($10^{-2}{\sim}10^{-3}$) in the newly developed regeneration medium. It was demonstrated that the strains showing high performances in the protoplast regeneration and solid growth medium were able to produce 5.8~6.4%(w/w) of ${\beta}$-D-glucan and 13~15 g/L of biomass in stable manners in suspended shake-flask cultures of P. linteus mycelia. In addition, cell mass increase was observed to be the most important in order to enhance ${\beta}$-D-glucan productivity during the course of strain improvement program, since the amount of ${\beta}$-D-glucan extracted from the cell wall of P. linteus mycelia was almost constant on the unit biomass basis. Therefore we fully investigated the fungal cell morphology, generally known as one of the key factors affecting cell growth extent in the bioreactor cultures of mycelial fungal cells. It was found that, in order to obtain as high cell mass as possible in the final production bioreactor cultures, the producing cells should be proliferated in condensed filamentous forms in the growth cultures, and optimum amounts of these filamentous cells should be transferred as active inoculums to the production bioreactor. In this case, ideal morphologies consisting of compacted pellets less than 0.5mm in diameter were successfully induced in the production cultures, resulting in shorter period of lag phase, 1.5 fold higher specific cell growth rate and 3.3 fold increase in the final biomass production as compared to the parallel bioreactor cultures of different morphological forms. It was concluded that not only the high-yielding but also the good morphological characteristics led to the significantly higher biomass production and ${\beta}$-D-glucan productivity in the final production cultures.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.1
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• pp.110-115
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• 2011

Shelf-life of brined baechu cabbage was extended by pasteurization at $65^{\circ}C$ for 30 min. Starters (Leu. citreum and Lab. plantarum) were added to the pasteurized brined cabbage to supply beneficial lactic acid bacteria during kimchi fermentation. Control kimchis made with baechu cabbage without pasteurization and no addition of the starters to the pasteurized cabbage kimchi were also prepared. The fermentation characteristics and health functionalities of DPPH free radical scavenging activities and in vitro anticancer effects in AGS human gastric cancer cells were compared. The pasteurized brined cabbage could not be fermented well and the functionalities were also low; however, the addition of starter(s), especially mixed starters of Leu. citreum and Lab. plantarum to the pasteurized brined cabbage, significantly increased the counts of lactic acid bacteria, hardness (texture) and overall acceptability in sensory evaluation. The free radical scavenging activities and the anticancer effects were also increased. The fermentation patterns of starter added kimchi prepared with pasteurized brined cabbage were similar to those of naturally fermented kimchi. It seemed that growth of lactic acid bacteria during kimchi fermentation contributed to increased taste and health functionality of kimchi.

• Tuberculosis and Respiratory Diseases
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• v.55 no.1
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• pp.59-68
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• 2003

Background : In intubated patients, cultures of endotracheal aspirates (EA) are apt to contamination throughout the endotracheal tube. Therefore, the identification of etiologic agents via conventional EA cultures is not always reliable. In order to differentiate a pulmonary infection from a non-infectious disease, and to identify the true etiologic agent of acute pulmonary infection, blinded protected specimen brushing (PSB) was used, and its efficacy evaluated. Methods : In 51 intubated patients, with suspected pneumonia, blind PSB were performed, and the results compared with blood and EA cultures. A protected specimen brush was introduced through the endotracheal tube, and settled at the affected large bronchus. A specimen brush was introduced to the expected region using the blind method. The tip of the brush was introduced with an aseptic technique after vigorously mixed for 1 minute in $1cm^3$ of Ringer's lactate solution. The specimens were submitted for quantitative culture within 15 minutes, with a culture being regarded as positive if the colony forming units were above $10^3/ml$. Results : Of the 51 patients, 15 (29.4%) had community-acquired pneumonia (CAP), 27 (52.9%) hospital-acquired pneumonia (HAP) and 9 (17.6%) non-infectious diseases. The sensitivity and specificity of the quantitative PSB culture for the diagnosis of pneumonia were 52.4 and 88.9%, respectively. The sensitivity and specificity of EA were 78.6 and 77.8%, respectively. The blind PSB was superior to the EA for the identification of true etiologic agents. Of 53 episodes of 27 HAP patients, MRSA (Methicillin-resistant staphylococcus aureus) (41.5%) was the most common causative agent followed by Pseudomonas aeruginosa (15.1%), Klebsiella sp. (7.5%) and Acinetobacter sp. (7.5%). Conclusions : As a simple, non-invasive diagnostic modality, the blind PSB is a useful method for the differentiation of a pulmonary infection from non-infectious diseases and to identify the etiologic agents in intubated patients. A blind PSB can be performed without bronchoscopy, so is safer, more convenient and cost-effectiveness for patients where bronchoscopy can not be performed.