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Seungjib JEON,Hyun Gi KOH,Mi Rae KIM,Young Jin KIM,Hyejeong HEO,Joon-Chul LEE,Yong Keun CHANG 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
Microalgae are promising resources for producing value-added products due to their rapid growth rate and high lipid content. Among products obtained from microalgae, the eicosapentaenoic acid (EPA) which is health supplement has gained attention because of the limitations on fish oil production. In this study, we optimized cultivation conditions of Nannochloropsis salina for enhancement of EPA production. The optimization process was carried out by response surface methodology (RSM) for studying the interactive effect of temperature and N concentration (NaNO₃) using central composite design. The RSM results showed an optimal level of 1.28 g/L for NaNO₃ and 21 ℃ for temperature, resulting in maximum EPA productivity of 14.4 ㎎/L/day. To understand the effect of optimal conditions on EPA production, we analyzed the lipid compositions and pigment contents. The glycolipids and chlorophyll a were found to be increased under optimal conditions. We also investigated mRNA expression levels of genes involved in EPA synthesis by quantitative real-time PCR and confirmed their positive contribution to EPA production.
Development of Serum-free Medium for Chinese Hamster Ovary Cell Line Producing Recombinant Protein
Na young HONG,Seungjib JEON,Mi Rae KIM,Hyejeong HEO,Sang Yeop LEE,Yong Jin KIM,Tae-Joon JEON,Joon-Chul LEE 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
Fetal bovine serum (FBS) has been used as an essential supplement in mammalian cell cultures. However, serumcontaining media have some disadvantages such as unclear composition, poor reproducibility and high risk of microbial contaminations. Recently, serum-free media has gained attention due to its uniform ingredients, excellent stability, and reproducibility. In this study, we developed serum-free media for recombinant Chinese hamster ovary (CHO) cells using design of experiments (DoE). Significant factors were selected using plackett-burman design, and the fractional factorial design was used to examine interactive effects of adopted components. In the optimal condition, the rCHO cells successfully showed higher maximum viable cell density up to 29x105 cells/mL on fourth day. Also, the optimization of components concentration was carried out by the response surface methodology for enhancing growth of rCHO cells.
Yong Jin KIM,Seungjib JEON,Na Young HONG,Hyejeong HEO,Sang Yeop LEE,Mi Rae KIM,Joon-Chul LEE 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
Transforming Growth Factor-β1 (TGF-β1) is a multifunctional cytokine involved in various biological activities, including differentiation, proliferation, apoptosis and matrix formation in a cell. The demand of TGF-β1 continuously increases in the biomedical field due to various functions of TGF-β1. Vector engineering is a fundamental approach to meet the demand by enhancing the production yield of recombinant proteins. In an effort to produce high amounts of the TGF-β1 for industrial application, we have constructed a mammalian expression system based on a modified pIRES vector with a murine dihydrofolate reductase (mDHFR) gene inserted for MTX-mediated gene amplification system. The signal sequence of TGF-β1 was replaced with that of human azurocidin, and a histidine tag was inserted immediately after the signal sequence to facilitate protein purification. In addition, woodchuck hepatitis virus post-transcriptional regulation element (wPRE) sequence was incorporated at the 3’ end of the TGF-β1 expression cassette for enhanced protein expression. As expected, the expression level of TGF-β1 was increased using engineered vector with wPRE sequences compared to that standard vector. This simple and efficient approach can be used in biomedical industry for the mass production of recombinant protein.