https://repository.kopri.re.kr/handle/201206/14822 2026-04-15T01:18:18Z https://repository.kopri.re.kr/handle/201206/16279 Title: Inorganic iodine and bromine speciation in Arctic snow at picogram-per-grams levels by IC-ICP-MS Authors: Frassati Stefano; Barbaro Elena; Rossetti Claudia; Cozzi Giulio; Turetta Clara; Scoto Federico; Roman Marco; Feltracco Matteo; Kim, Kitae; Barbante Carlo; Gambaro Andrea; Spolaor Andrea Abstract: Iodine and bromine play central roles in polar atmospheric chemistry: iodine influences the atmospheric oxidative capacity and can generate cloud condensation nuclei, while bromine participates in ozone depletion reactions, known as bromine explosions. Here we present a very sensitive analytical method for Br and I speciation by coupling the ion chromatography system (IC) with an inductively coupled plasma sector field mass spectrometer (ICP-SFMS). We achieved sub-picogram-per gram (pg g-1) as limits of detection (LODs) ranging from 0.4 pg g-1 for I-, 0.8 pg g-1 for IO3-, 4 pg g-1 for Br-, and 1 pg g-1 for BrO3-, respectively. These values represent a decrease of up to 30 times compared to the LODs reported in other studies. The method was validated using deep snow samples from the Svalbard Islands, collected at the end of the polar night to quantify various oxidized compounds during their seasonal minimum. In the future, this method could prove useful in the paleoclimatic study of ice cores and snow, as well as in ice chemistry research. 2024-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/14903 Title: Production of Molecular Iodine via a Redox Reaction between Iodate and Organic Compounds in Ice Authors: Kim, Kitae; Kim, Bomi; 안용윤; Tran Khen Duy; Truong Hanh Thi My; Kim Jungwon Abstract: The abiotic mechanism of molecular iodine (I-2) production from iodate (IO3-) remains largely unknown. Here, we demonstrate the production of I-2 in the presence of IO3- and organic compounds in ice. When the solution containing IO3- (100 mu M) and furfuryl alcohol (100 mu M) at pH 3.0 was frozen at -20 degrees C, 13.1 mu M of I-2 was produced with complete degradation of furfuryl alcohol after 20 min. However, there was little change in the IO3- and furfuryl alcohol concentrations in water at 25 degrees C. The production of I-2 in ice is due to the freeze concentration effect, which induces the accumulation of IO3-, furfuryl alcohol, and protons in the ice grain boundaries. This behavior facilitated the production of I-2 via a redox reaction between IO3- and organic compounds. The production of I-2 increased with increasing furfuryl alcohol concentration and decreasing pH. However, freezing temperature had a minor effect on the maximum production of I-2. The production of I-2 is highly dependent on the type of organic compounds. It was higher for organic compounds with higher electron-donating properties. This study suggests a new mechanism for I-2 production, which is helpful for predicting precisely the atmospheric I-2 budget in cold regions. 2023-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/14955 Title: Detoxification of arsenite by iodide in frozen solution Authors: Nguyen Quoc Anh; Kim, Bomi; Chung, Hyun Young; 안용윤; Kim, Kitae Abstract: The oxidation of arsenite (As(III)) to arsenate (As(V)) has received significant attention because it helps mitigate the hazardous and adverse effects of As(III) and subsequently improves the effectiveness of arsenic removal. This study developed an efficient freezing technology for the oxidative transformation of As(III) based on iodide (I- ). For a sample containing a very low concentration of 20 μM As(III) and 200 μM I - frozen at - 20 -C, approximately 19 μM As(V) was formed after reaction for 0.5 h at pH 3. This rapid conversion has never been achieved in previous studies. However, As(V) was not generated in water at 25 -C. The acceleration of the oxidation of As(III) by I - in ice may be attributed to the freeze-concentration effect. During freezing, all components (i.e., As(III), I - , and protons) are highly concentrated in the ice grain boundary regions, resulting in thermodynamically and kinetically favorable conditions for the redox reaction between As(III) and I - . The efficiency of the oxidation of As(III) using I - increased at high I - concentrations and low pH values. The low freezing temperature (below - 20 -C) hindered the oxidative transformation of As(III) by I - . The efficiency of the oxidation of As(III) significantly increased using a fixed initial concentration of I - by subjecting the system to six freezing-melting cycles. The outcomes of this study suggest the possibility of the self-detoxification of As(III) in the natural environment, indicating the potential for developing an eco-friendly method for the treatment of As(III)- contaminated areas in regions with a cold climate. It also demonstrates radical remediation to almost completely remove a very small amount of As(III) that was input in As(III)-contaminated wastewater detoxification, a benchmark that existing methods have been unable to achieve. 2023-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/14918 Title: Heterologous protein production using Psychrobacter sp. PAMC 21119 analyzed with a green fluorescent protein-based reporter system Authors: 이민주; Kim, Bomi; Kim, Kitae; Lee, Jun Hyuck; Do, Hackwon Abstract: Insolubility and low expression are typical bottlenecks in the production of proteins for studying their function and structure using X-ray crystallography or nuclear magnetic resonance spectroscopy. Cold-active enzymes from polar microorganisms have unique structural features that render them unstable and thermolabile, and are responsible for decreased protein yield in heterologous expression systems. To address these challenges, we developed a heterologous protein expression system using a psychrophilic organism, Psychrobacter sp. PAMC 21119, as a protein expression host with its own promoter. We screened 11 promoters and evaluated their strength using quantitative real-time polymerase chain reaction and a reporter system harboring the SfGFP gene. The highest expression was achieved using promoters RH96_RS13655 (P21119_20930) and RH96_RS15090 (P21119_23410), regardless of the temperature used. The p20930 strain exhibited a maximum expression level 19.6-fold higher than that of its control at 20 °C and produced approximately 0.5 mg of protein per gram of dry cell weight. To our knowledge, this is the first report of a low-temperature recombinant protein expression system developed using Psychrobacter sp. that can be used to express various difficult-to-express and cold-active proteins. 2023-01-01T00:00:00Z