Publications by authors named "HoYong Kim"

Lignin nanoparticles (LNPs) exhibit application potential in fields such as ultraviolet (UV) shielding, antioxidant materials, and water purification owing to their versatile chemical structure. However effective, nontoxic solvent-based strategies to synthesize LNPs with diverse morphologies have not been reported. This study presents a continuous biorefinery method to produce monodisperse LNPs with diverse morphologies from isopropanol-solubilized lignin (IPA-lignin).

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Lignin-based supports for metal nanoparticles (NPs) have attracted significant attention due to their abundant functional groups that facilitate NPs loading. However, many studies involve a two-step process: fabricating lignin particles and then reducing metal ions to NPs using physical energy consumption or chemical reduction. A one-step in-situ reduction method for NP synthesis on carrier surfaces, eliminating energy consumption, is needed for environmentally friendly and sustainable approach.

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We propose a closed-loop pretreatment process, wherein volatiles produced during steam explosion pretreatment were recovered and reintroduced as acid catalysts into the pretreatment system. The volatiles were separated through a drastic decompression process followed by a steam explosion process and recovered as a liquified catalyst (LFC) through a heat exchanger. The LFC effectively served as an acid catalyst for hemicellulose hydrolysis, significantly decreasing residence time from 90 min to 30 min to achieve 80 % conversion yield at 170 °C.

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The intricate structure of lignin, characterized by a mix of hydrophilic components and hydrophobic structures from its aliphatic and aromatic constituents, poses challenges in creating monodisperse particles. This is due to the need for precise modulation of self-assembly kinetics. Herein, we explore a correlation between the substructure of lignin and its capacity for self-assembly.

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Pseudomonas putida is a promising strain for lignin valorisation. However, there is a dearth of stable and efficient systems for secreting enzymes to enhance the process. Therefore, a novel secretion system for recombinant lignin-depolymerising peroxidase was developed.

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Unlabelled: Here we have proposed fuzzy portfolio selection model using stochastic correlation (FPSMSC) to overcome limitations both in fuzzy and stochastic world. The newly proposed model not only gets harmonious efficient frontier, but also considers the future movement of stock prices based on fuzzy expertise knowledge. The investment weights of the model have been optimized based on the monthly return data of 18 stocks listed in S&P500 from October 2011 to September 2015.

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Lignin has potential as a substitute for natural antioxidants in cosmetics and food industries due to its radical scavenging ability and price competitiveness. The antioxidant activity of lignin depends on its structural properties, and they accordingly have synergy with natural antioxidants. Based on the structural characteristics, the antioxidant activity of ethanol organosolv lignin (EOL) and synergy with myricetin were investigated.

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In this study, the physicochemical properties of torrefied biomass (larch and yellow poplar) were investigated based on torrefaction temperature. The effect of torrefied biomass on the hydrophobicity and mechanical properties of a polylactic acid (PLA) composites was evaluated. Hemicellulose was removed from the biomass during torrefaction, whereas the cellulose and lignin contents increased slightly.

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Commonly, lignin macromolecules have limitations in application to the thermoplastics industries due to poor dispersibility and interfacial compatibility within ligno-bioplastics. In this study, the dispersibility and interfacial compatibility of ethanol organosolv lignin (EOL) in PLA-based ligno-bioplastic were improved by enhancing the thermoplasticity via oxypropylation. Further, three types of EOLs extracted from different severity conditions were applied to investigate the effect of the structural characteristics of EOLs on the changes in the thermal properties.

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This study assesses the economic performance of a biorefinery producing xylo-oligosaccharides (XOS) from miscanthus by autohydrolysis and purification based on a rigorous model developed in ASPEN Plus. Varied biorefinery capacities (50-250 oven dry metric ton (ODMT)/day) and three XOS content levels (80%, 90%, 95%) are analyzed. The XOS minimum selling price (XOS MSP) is varied between $3,430-$7,500, $4,030-$8,970, and $4,840-$10,640 per metric ton (MT) for 80%, 90%, and 95% content, respectively.

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Endo-1,4-β-xylanase is one of the most important enzymes employed in biorefineries for obtaining fermentable sugars from hemicellulosic components. Herein, we aimed to improve the catalytic performance of Bacillus circulans xylanase (Bcx) using a structure-guided rational design. A systematic analysis of flexible motions revealed that the R49 component of Bcx (i) constrains the global conformational changes essential for substrate binding and (ii) is involved in modulating flexible motion.

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is known as attractive biomass, and it has been utilized for eucalyptus oil, furniture, and pulp and paper production that causes a significant amount of byproducts. Liquid hot water treatment depending on combined severity factor (CSF) was subjected to isolate hemicellulose fraction from and to produce xylooligosaccharides (XOS). The xylan extraction ratio based on the initial xylan content of the feedstock was maximized up to 77.

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Advances in scientific technology in the early twentieth century have facilitated the development of synthetic plastics that are lightweight, rigid, and can be easily molded into a desirable shape without changing their material properties. Thus, plastics become ubiquitous and indispensable materials that are used in various manufacturing sectors, including clothing, automotive, medical, and electronic industries. However, strong physical durability and chemical stability of synthetic plastics, most of which are produced from fossil fuels, hinder their complete degradation when they are improperly discarded after use.

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Sucrose utilization has been established in Escherichia coli strains by expression of Mannheimia succiniciproducens β-fructofuranosidase (SacC), which hydrolyzes sucrose into glucose and fructose. Recombinant E. coli strains that can utilize sucrose were examined for their abilities to produce poly(3-hydroxybutyrate) [P(3HB)] and poly(3-hydroxybutyrate-co-lactate) [P(3HB-co-LA)] from sucrose.

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We investigate minimal control power (MCP) for controlled dense coding defined by the channel capacity. We obtain MCPs for extended three-qubit Greenberger-Horne-Zeilinger (GHZ) states and generalized three-qubit W states. Among those GHZ states, the standard GHZ state is found to maximize the MCP and so does the standard W state among the W-type states.

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The main purpose of this study was to investigate the glucan conversion rate after enzymatic hydrolysis depending on the treatment methods and conditions with changes in the chemical composition of treated solid fraction of Jabon Merah. The glucan conversion rate (17.4%) was not significantly improved after liquid hot water treatment (1st step) even though most of the hemicellulose was dissolved into liquid hydrolysate.

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Recent techno-economic studies of proposed lignocellulosic biorefineries have concluded that creating value from lignin will assist realization of biomass utilization into valuable fuels, chemicals, and materials due to co-valorization and the new revenues beyond carbohydrates. The pretreatment step within a biorefinery process is essential for recovering carbohydrates, but different techniques and intensities have a variety of effects on lignin. Acidic and alkaline pretreatments have been shown to produce diverse lignins based on delignification chemistry.

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The aims of this study were to extract pectin from rapeseed cake (RSC) by enzymatic hydrolysis using commercial enzymes (Celluclast and Alcalase) and to investigate the effects of different reaction conditions, such as enzymatic hydrolysis time, enzyme-RSC ratio, and Celluclast-Alcalase ratio, on the degradation of RSC and pectin yield. RSC was treated using a combined extraction process that consisted of a fat removal process, enzymatic hydrolysis, and isopropanol/ethanol precipitation. After the fat removal process and enzymatic hydrolysis, defatted-RSC was suitably decomposed, and the loss of liberated reducing sugars was minimized when the hydrolysis condition reached a hydrolysis time of 270 min or an enzyme-RSC ratio of 1:50.

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The aim of this study was to investigate the effects of different acid pretreatments on the hydrolysis of biomass and ethanol production. Maleic, oxalic, and sulfuric acids were used individually as catalysts. The fermentable sugar concentration in hydrolysate was high at more than 30 g/L, which obtained at the dicarboxylic acid pretreatment.

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This study examined the interrelation between the biodegradation of polychlorinated biphenyls (PCBs) by Ceriporia sp. ZLY-2010 and its fungal enzyme systems. The degradation rates of Aroclor 1254 and 1260 were 29.

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In this study, rapeseed cake (RSC) was used as a source of pectins due to its high carbohydrate content. Different combinations of treatments were applied to investigate the effect of combination processes on the extraction of pectin from RSC. The treatments chosen for combination were a fat removal process (FRP) (solvent extraction using an alcohol-benzene mixture), a chemical treatment (CT) (hydrolysis using 1% hydrochloric acid), and an enzymatic hydrolysis (EH).

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Okara, an organic waste product obtained from soy milk production, was used with copper chloride or sodium borate to formulate new wood preservatives as a substitute for expensive wood preservatives, such as copper-azole-based preservatives and ammoniacal copper quaternary. Before formulating the preservatives, okara was hydrolyzed by enzymes (cellulase, pectinase, and protease) to augment penetration and fix the biocide salts of the preservatives into wood blocks. The preservatives were injected into wood blocks by vacuum pressure to measure the treatability of the preservatives.

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Enzymatic saccharification of lignocellulosic biomass was performed using culture filtrates of brown rot fungi including Gloeophyllum sepiarium, Fomitopsis pinicola, and Laetiporus sulphureus. Biological treatment with white rot fungi was used as pretreatment prior to enzymatic saccharification. Endoglucanase, beta-glucosidase, xylanase and cellobiohydrolase activities were determined from concentrated culture filtrates of the brown rot fungi.

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The aim of this study was to determine the iron status of infants who consumed porridge cooked in water with added ferrous sulphate. A total of 234 infants, aged 6-12 months, were recruited from 36 nurseries in the Democratic Peoples Republic of Korea (DPRK North Korea) and randomly divided into iron (Fe) and placebo groups. At baseline, almost half the children had Hb<110 g/L and no significant differences between the two groups were found with regard to hemoglobin concentration and anemia prevalence.

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