• Mycobiology
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• 제41권4호
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• pp.221-224
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• 2013

Aphids are one of the most destructive pests in crop production such as pepper, cucumber, and eggplants. The importance of entomopathogenic fungi as alternative pest control agents is increasing. Conidia of entomopathogenic fungi are influenced by environmental conditions, such as temperature and relative humidity, and cause slow and fluctuating mortality. These factors have prevented wider application and use of biocontrol agents. For investigation of means of mitigation of such problems, we conducted bioassays with 47 fungal culture filtrates in order to evaluate the potential of secondary metabolites produced by entomopathogenic fungi for use in aphid control. Among 47 culture filtrates cultured potato dextrose broth, filtrate of Beauveria bassiana Bb08 showed the highest mortality (78%) against green peach aphid three days after treatments. Filtrate of Bb08 cultured in Adamek's medium showed higher toxicity as 100% to third instar nymphs of the aphid compared with seven other filtrates cultured in different broths amended with colloidal chitin or oil. The culture filtrates and fungal cultures from media amended with colloidal chitin or oil had lower control efficacies than filtrates without these additives in three different media. These results indicate that the fungal culture fluid or culture filtrate of B. bassiana Bb08 cultured in Adamek's medium has potential for development as a mycopesticide for aphid control.

• 한국식품저장유통학회지
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• 제30권6호
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• pp.1072-1081
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• 2023

본 연구는 발효에 의한 생리기능성을 조사하여 기능성 식품 소재 개발을 위한 기초자료를 제공하고자 Lactobacillus 속을 이용한 작두콩 발효액을 제조하여 항산화, 항염증, 항균 활성을 평가하였다. 총폴리페놀 및 플라보노이드 함량은 균주의 종류에 상관없이 발효 후 유의적으로 낮은 결과를 보였으며(p<0.05), 항산화 활성을 측정한 DPPH 라디칼 소거 활성 또한 발효에 따른 효과가 나타나지 않았다. 그러나 NO 소거 활성으로 항염증 활성을 측정한 결과, 발효 후 농도 의존적으로 증가하는 것을 확인하였으며, L. plantarum로 발효한 발효액보다 L. brevis로 발효한 발효액의 항염증 활성이 더 높았음을 확인하였다. 작두콩 발효액의 항균 활성을 측정한 결과, 녹농균인 Pseudomonas aeruginosa, 포도상구균인 Staphylococcus sp., 대장균인 Escherichia coli에 대한 억제 효과가 우수하였으며, 세포 독성 측정 결과, 모든 실험군에서 대식세포인 RAW 264.7에 대한 독성을 보이지 않았다. 이와 같은 결과는 발효에 따른 항염증 및 항균 활성이 증가하였음을 보여주었으며, 이를 토대로 다양한 바이오 및 식품산업 분야에 효과적으로 활용될 수 있을 것으로 생각된다. 다만 추후에는 발효 조건의 확립과 항염증 및 항균 활성에 대한 정확한 메커니즘 연구가 필요할 것으로 판단된다.

• Advances in nano research
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• 제9권1호
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• pp.59-67
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• 2020

Filter cake formation during rotary drilling operation is an unavoidable scenario, hence there is need for constant improvement in the approaches used in monitoring the cake thickness growth in order to prevent drill-string sticking. This study proposes an improved model that predicts the growth of mud cake thickness overtime with the consideration of the addition of nanoparticles in the formulated drilling fluid system. Ferric oxide, titanium dioxide and copper oxide nanoparticles were used in varying amounts (2 g, 4 g and 6 g), and filtration data were obtained from the HPHT filtration test. The filter cakes formed were further analyzed with scanning electron microscope to obtain the morphological characteristics. The data obtained was used to validate the new filtrate loss model. This model specifically presents the concept of time variation in filter cake formation as against the previous works of constant and definite time. Regression coefficient which is a statistical measure was used to validate the new model and the predicted results were compared with the API model. The new model showed R² values of 99.9%, and the predictions from the proposed filtration model can be said to be more closely related to the experimental data than that predicted from the API model from the SSE and RMSE results.

• 한국미생물·생명공학회지
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• 제25권5호
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• pp.527-533
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• 1997

From apple skin, we isolated a bacterial strain which strongly inhibited the growth of apple white rot fungus, Botryosphaeria dothidea. The isolated strain, designated as SS279, was identified to be the genus Bacillus. The antifungal activity of Bacillus sp. SS279 was found in the culture filtrate. The production of antifungal substances occurred during logarithmic phase and was the highest when cultures reached the stationary growth phase. The optimum ranges of temperature and pH for its production were 25-30$\circ$C and 4.5-9.0, respectively. The culture filtrate of Bacillus sp. SS279 exhibited a strong inhibitory effect on the spore germination and germ tube elongation of B. dothidea. Autoclaved culture filtrate of Bacillus sp. SS279 showed only a slight decrease in antifungal activity, indicating that the Bacillus sp. SS279 produce heat-stable antifungal substances. In in vivo bioassay, Bacillus sp. SS279 also showed antagonistic activity against apple white rot caused by B. dothidea.

• Asian-Australasian Journal of Animal Sciences
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• 제15권4호
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• pp.602-609
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• 2002

Lao-chao is a traditional Chinese fermented rice product with a sweet and fruity flavor, containing high levels of glucose, a little alcohol and milk-clotting characteristics. In order to optimize commercial production of lao-chao, Rhizopus javanicus and Saccharomyces cerevisiae were selected as the mold and yeast starter, respectively. A commercial mixed starter (chiu-yao) was used as control. Fermentation of the experimental combination revealed a sharp drop in pH (to 4.5) on the fourth day, remaining constant thereafter. Content of reducing sugars gradually decreased throughout the entire fermentation period. Of the free amino acids, higher quantities of alanine, leucine, proline, glutamic acid, glutamine and $NH_3$ were noted. For sugars, glucose revealed the highest concentration, while organic acid levels, including those for oxalic, lactic, citric and pyroglutamic acid, increased throughout the fermentation period. Twenty-one compounds were identified by gas chromatography from aroma concentrates of the lao-chao culture filtrate, prepared using the headspace method. For the flavor components, higher quantities of ethanol, fusel oil and ester were determined in both culture filtrates. In regard to the evaluation of yogurt-like product, there were significant differences in alcoholic smell, texture and curd firmness.

• Asian-Australasian Journal of Animal Sciences
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• 제14권10호
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• pp.1470-1476
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• 2001

Kou Woan Lao is an oriental-style dairy product, which is coagulated by milk-clotting enzyme from the culture filtrate of lao-chao. The product appears smooth, sweet, slightly wine flavour, and the flavour differs from yogurt. The aim of this study was to search for the optimum model to shorten the period of manufacture, and to improve the quality of Kou Woan Lao. A response surface design was used for studying the effects of addition of carrageenan, locust bean gum, and culture filtrate from lao-chao on the curd firmness, viscosity, and syneresis. Results indicated that the best rheological property, preservative quality and acceptability of Kou Woan Lao could be obtained by the combination of 0.22% carrageenan, 0.21 % locust bean gum and 12% culture filtrate from lao-chao. The curd firmness, viscosity and syneresis of resultant product were 29.3 g, 21,347.7 cps, and 8.92%, respectively and the microstructure of the curd revealed a relatively complete three-dimensional spider web-like structure.

• Mycobiology
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• 제44권4호
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• pp.338-342
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• 2016

The culture filtrate of Lentinula edodes shows potent antimicrobial activity against the plant pathogenic bacteria Ralstonia solanacearum. Bioassay-guided fractionation was conducted using Diaion HP-20 column chromatography, and the insoluble active compound was not adsorbed on the resin. Further fractionation by high-performance liquid chromatography (HPLC) suggested that the active compounds were organic acids. Nine organic acids were detected in the culture filtrate of L. edodes; oxalic acid was the major component and exhibited antibacterial activity against nine different phytopathogenic bacteria. Quantitative analysis by HPLC revealed that the content of oxalic acid was higher in the water extract from spent mushroom substrate than in liquid culture. This suggests that the water extract of spent L. edodes substrate is an eco-friendly control agent for plant diseases.

• 상하수도학회지
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• 제23권2호
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• pp.215-222
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• 2009

This study compares the performance of the filters with various media in pretreatment of seawater desalination by reverse osmosis. For this purpose, Masan bay seawater is used as raw water. The filter performance is evaluated by the filtrate quality and the head loss development. Five media is selected in this study: anthracite, $Filtralite^{(R)}$, sand, Pumice, $AFM^{(R)}$. These media are used in combination for dual media filter and alone for mono media filter. The comparison results show that NC0.8-1.6 is the best $Filtralite^{(R)}$. The dual media filter of NC0.8-1.6 and sand outperformed other filters in particle removal. The dual media filter of anthracite and sand showed good performance in organic removal. The mono media filter of Pumice produced the similar filtrate quality as the mono media filter of sand although the effective size of Pumice is considerably greater than that of sand. Due to big size, head loss development is maintained slow in the filtration of Pumice.

• 상하수도학회지
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• 제23권2호
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• pp.207-214
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• 2009

This study examines the optimum filtration conditions in pretreatment of seawater desalination by reverse osmosis. For this purpose, Masan bay seawater is treated through a gravity filter column while $FeCl_3$ is added as coagulant. The conditions of coagulantd osage, media depth, filtration rate, and backwash time are evaluated. The study results show that the filtrate quality improved with increasing coagulant dosage, but head loss rapidly increased. After 4mg/L, the unit filter run volume reduced to less than $200m^3/m^2$. Considering the head loss development, 4mg/L is determined as the optimum dosage. The better filtrate qualities are obtained with depth of 100cm than that of 80cm. The two stage filtration, which outperformed the single stage filtration, is suggested for treatment of Masan bay. The filtration rate of 5m/h is decided as the optimum condition considering the head loss development. At 10m/h, the filtrate quality deteriorated even though the extent was minimal, and head loss increased rapidly. The backwash time of 10 min is decided appropriate.

• Journal of the Korean Wood Science and Technology
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• 제47권2호
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• pp.210-220
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• 2019

This work aimed to evaluate the influence of culture conditions on laccase production in the co-culture of wood-rotting fungus with Trichoderma sp. The effects of infection extent, infection time, and culture filtrate of Trichoderma sp. on the laccase production by wood-rotting fungus in co-culture were examined. T. rubrum LKY-7 and T. longibrachiatum were selected as fungi which are effective in co-culture for laccase production. A significant increase in laccase activity was observed when T. rubrum LKY-7 was co-cultured with T. longibrachiatum in glucose-peptone liquid medium, yielding an increase of more than 5 times in laccase activity, as compared with control. Laccase production by T. rubrum LKY-7 during co-culturing was significantly influenced by the infection extent and the infection time of T. longibrachiatum. Maximal laccase activity was obtained when T. rubrum LKY-7 culture was infected by T. longibrachiatum after 3 days of cultivation at an inoculum size ratio of 0.5 to 1. The addition of culture filtrate or autoclaved mycelium of T. longibrachiatum to T. rubrum LKY-7 culture did not significantly enhance laccase production by T. rubrum LKY-7 as compared with control (mono cultures of T. rubrum LKY-7).