https://repository.kopri.re.kr/handle/201206/5095 2026-04-23T05:16:56Z https://repository.kopri.re.kr/handle/201206/10502 Title: Enhancing Lipid Production in the Arctic Microalga Chlamydomonas sp. KNM0029C by Using Statistical Optimization of Medium Components Authors: Kim, Eun Jae; Jung, Woongsic; Kim, Sanghee; Choi, Han-Gu; Han, Se Jong Abstract: A sequential statistical optimization was applied tothe components of Tris-acetate-phosphate (TAP) medium, toenhance the cell density and lipid production of Arcticmicroalga Chlamydomonas sp. KNM0029C. The evaluationwas preformed through an elimination process and Plackett-Burman design to select for significant factors, contributingtoward cell growth. NH4Cl, MgSO4·7H2O, potassium phosphate,and trace elements were established as the effectivecomponents and used as variable factors in Box-Behnken designtest, - a response surface methodology (RSM). The final optimizedconcentrations were 0.54, 0.16, 0.04, and 0.08 g/L ofNH4Cl, MgSO4·7H2O, potassium phosphate, and trace elements,respectively. Overall, 9.9% enhanced lipid productionwas achieved by using optimized TAP medium at 4°C. Theresults of the present study could potentially contributetoward large-scale lipid production at low temperatures. 2019-09-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/12300 Title: Lipid formation by Arctic microalga Chlamydomonas sp. KNF0008 at low temperature Authors: Kim, Eun Jae; Jung, Woongsic; Lim, Suyoun; Kim, Sanghee; Choi, Han-Gu; Han, Se Jong Abstract: In the present study, we introduce a new lipid-producing microalga, Chlamydomonas sp. KNF0008, collected from the Arctic. This strain was capable of growing at temperatures ranging from 4 oC to 20 oC, and the highest cell density was measured at 15 oC and 100 μmol photons m2 s1 light intensity under continuous shaking and external aeration. KNF0008 showed the elevated accumulation of lipid bodies under nitrogen-deficient conditions, rather than under nitrogen-sufficient conditions. Fatty acid production of KNF0008 was 4.2-fold (104 mg L1) higher than that of C. reinhardtii CC-125 at 15 oC in Bold’s Basal Medium. The dominant fatty acids were C16:0, C16:4, C18:1, and C18:3, and unsaturated fatty acids (65.69%) were higher than saturated fatty acids (13.65%) at 15oC. These results suggested that Arctic Chlamydomonas sp. KNF0008 could possibly be utilized for production of biodiesel during periods of cold weather because of its psychrophilic characteristics. 2019-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/5811 Title: Enzymatic modification by point mutation and functional analysis of an omega-6 fatty acid desaturase from Arctic Chlamydomonas sp. Authors: Jung, Woongsic; Kim, Sanghee; Choi, Han-Gu; Kang, Sung-Ho; Han, Se Jong; Kim, Eun Jae Abstract: Arctic Chlamydomonas sp. is a dominant microalgal strain in cold or frozen freshwater in the Arctic region. The full-length open reading frame of the omega-6 fatty acid desaturase gene (AChFAD) was obtained from the transcriptomic database of Arctic Chlamydomonas sp. from the KOPRI Culture Collection of Polar Microorganisms (KCCPM). Amino acid sequence analysis indicated the presence of three conserved histidine-rich segments as unique characteristics of omega-6 FADs, and three transmembrane regions transported to plastidic membranes by chloroplast transit peptides in the N-terminal region. The AChFAD6 desaturase activity was examined by expressing wild-type and V254A mutant (Mut-AChFAD6) heterologous recombinant proteins. Quantitative gas chromatography indicated that the concentration of linoleic acids in AChFAD6-transformed cells increased more than three-fold (6.73 ± 0.13 mg g-1 dry cell weight (DCW)) compared with cells transformed with vector alone. In contrast, transformation with Mut-AChFAD6 increased the concentration of oleic acid to 9.23 ± 0.18 mg g-1 DCW, indicating a change in enzymatic activity to mimic that of stearoyl-CoA desaturase (SCD). These results demonstrate that AChFAD6 of Arctic Chlamydomonas sp. increases membrane fluidity by enhancing desaturating C18 fatty acids and facilitates production of large quantities of linoleic fatty acids in prokaryotic expression systems. 2017-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/9062 Title: Development of high cell density cultures of microalga for the production of bio-fuel suing manure anaerobic digestate Authors: Han, Se Jong 2016-12-12T00:00:00Z