• 한국균학회지
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• 제31권3호
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• pp.181-186
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• 2003

담자균류 80여종에서 laccase 고생산 균주(Fomitella fraxinea; 장수버섯)를 선발하고, F. fraxinea를 이용한 리그닌 분해효소의 생산 및 효소의 대량생산 조건을 검토하였다. 먼저 배지 조성에 따른 생산성을 조사한 결과 Cu등의 무기물의 첨가 유무에 따라 생산되는 효소가 달랐다. 무기물이 첨가되지 않은 배지(Medium I)에서는 manganese peroxidase가 생산되었고, 무기물이 첨가된 배지(Medium II)에서는 laccase가 생산되었는데 플라스크 배양 18일째에는 5.43 U/ml, 20일째에는 5.56 U/ml의 효소활성이 나타났다. 배양방법에서 영양이 충분한 조건에서는 정치배양보다는 진탕배양(120 rpm)에서 효소의 활성이 높았다. 이 균주를 이용한 laccase 대량생산 실험에는 jar fermentor, balloon type bioreactor, air-sparging fermentor를 이용하였다. laccase는 jar fermentor와 air-sparging formentor에서 3,540 U/ml(8일), 3,100 U/ml(6일)의 생산성을 나타내었다. Balloon type bioreactor는 균사의 생장은 좋았지만 효소는 생산되지 않았다. F. fraxinea를 사용하여 air-sparging fermentor로 scale up하여 laccase의 대량생산을 할 수 있다고 판단된다.

• The Plant Pathology Journal
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• 제33권3호
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• pp.337-344
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• 2017

To develop a commercial product using the mycoparasitic fungus Simplicillium lamellicola BCP, the scale-up of conidia production from a 5-l jar to a 5,000-l pilot bioreactor, optimization of the freeze-drying of the fermentation broth, and preparation of a wettable powder-type formulation were performed. Then, its disease control efficacy was evaluated against gray mold diseases of tomato and ginseng plants in field conditions. The final conidial yields of S. lamellicola BCP were $3.3{\times}10^9conidia/ml$ for a 5-l jar, $3.5{\times}10^9conidia/ml$ for a 500-l pilot vessel, and $3.1{\times}10^9conidia/ml$ for a 5,000-l pilot bioreactor. The conidial yield in the 5,000-l pilot bioreactor was comparable to that in the 5-l jar and 500-l pilot vessel. On the other hand, the highest conidial viability of 86% was obtained by the freeze-drying method using an additive combination of lactose, trehalose, soybean meal, and glycerin. Using the freeze-dried sample, a wettable powder-type formulation (active ingredient 10%; BCP-WP10) was prepared. A conidial viability of more than 50% was maintained in BCP-WP10 until 22 weeks for storage at $40^{\circ}C$. BCP-WP10 effectively suppressed the development of gray mold disease on tomato with control efficacies of 64.7% and 82.6% at 500- and 250-fold dilutions, respectively. It also reduced the incidence of gray mold on ginseng by 65.6% and 81.3% at 500- and 250-fold dilutions, respectively. The results indicated that the new microbial fungicide BCP-WP10 can be used widely to control gray mold diseases of various crops including tomato and ginseng.

• Journal of Microbiology and Biotechnology
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• 제31권10호
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• pp.1430-1437
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• 2021

Cronobacter sakazakii is an opportunistic pathogenic bacterium found in powdered infant formula and is fatal to neonates. Antibiotic resistance has emerged owing to overuse of antibiotics. Therefore, demand for high-yield bacteriophages as an alternative to antibiotics has increased. Accordingly, we developed a modified mass-production method for bacteriophages by introducing a two-stage self-cycling (TSSC) process, which yielded high-concentration bacteriophage solutions by replenishing the nutritional medium at the beginning of each process, without additional challenge. pH of the culture medium was monitored in real-time during C. sakazakii growth and bacteriophage CS01 propagation, and the changes in various parameters were assessed. The pH of the culture medium dropped to 5.8 when the host bacteria reached the early log phase (OD₅₄₀ = 0.3). After challenge, it decreased to 4.65 and then recovered to 4.94; therefore, we set the optimum pH to challenge the phage at 5.8 and that to harvest the phage at 4.94. We then compared phage production during the TSSC process in jar-type bioreactors and the batch culture process in shaker flasks. In the same volume of LB medium, the concentration of the phage titer solution obtained with the TSSC process was 24 times higher than that obtained with the batch culture process. Moreover, we stably obtained high concentrations of bacteriophage solutions for three cycles with the TSSC process. Overall, this modified TSSC process could simplify large-scale production of bacteriophage CS01 and reduce the unit cost of phage titer solution. These results could contribute to curing infants infected with antibiotic-resistant C. sakazakii.