• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.135-144
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• 2016

Due to the high price volatility and environmental concern of petroleum, biofuels such as bioethanol produced from lignocellulosic biomass have attracted much attention. It is also expected that the amount of lignin residue generated from pretreatment of lignocellulosic biomass will increase as the volume of cellulosic bioethanol increases. Lignin is a natural aromatic polymer and has very complex chemical structures with chemical functional groups. Chemical modification of lignin such as oxypropylation and epoxidation has also been applied to the production of value-added bioplastics such as polyurethane and polyester with enhanced thermal and mechanical properties. In addition, lignin can be used for carbon fiber production in automobile industries. This review highlights recent progresses in utilizations and chemical modifications of lignin for the production of bioplastics, resins, and carbon fiber.

• Journal of Microbiology and Biotechnology
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• v.31 no.3
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• pp.387-397
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• 2021

There is growing interest in the production of microalgae-based, high-value by-products as an emerging green biotechnology. However, a cultivation platform for Oocystis sp. has yet to be established. We therefore examined the effects of bacterial culture additions on the growth and production of valuable compounds of the microalgal strain Oocystis sp. KNUA044, isolated from a locally adapted region in Korea. The strain grew only in the presence of a clear supernatant of Sphingomonas sp. KNU100 culture solution and generated 28.57 mg/l/d of biomass productivity. Protein content (43.9 wt%) was approximately two-fold higher than carbohydrate content (29.4 wt%) and lipid content (13.9 wt%). Oocystis sp. KNUA044 produced the monosaccharide fucose (33 ㎍/mg and 0.94 mg/l/d), reported here for the first time. Fatty acid profiling showed high accumulation (over 60%) of polyunsaturated fatty acids (PUFAs) compared to saturated (29.4%) and monounsaturated fatty acids (9.9%) under the same culture conditions. Of these PUFAs, the algal strain produced the highest concentration of linolenic acid (C18:3 ω3; 40.2%) in the omega-3 family and generated eicosapentaenoic acid (C20:5 ω3; 6.0%), also known as EPA. Based on these results, we suggest that the application of Sphingomonas sp. KNU100 for strain-dependent cultivation of Oocystis sp. KNUA044 holds future promise as a bioprocess capable of increasing algal biomass and high-value bioactive by-products, including fucose and PUFAs such as linolenic acid and EPA.

• Korean Journal of Agricultural Science
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• v.49 no.2
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• pp.317-330
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• 2022

Recently, the policy regarding climate change in Korea and overseas has been to promote the utilization of forest biomass to achieve net zero emissions. In addition, with the implementation of the unused forest biomass system in 2018, the size of the Korean market for manufacturing wood pellets and wood chips using unused forest biomass is rapidly expanding. Therefore, it is necessary to estimate the total amount of unused forest biomass that can be used as an energy source and to identify the capacity that can be continuously produced annually. In this study, we estimated the actual forest area that can be produced of logging residue and the potential amount of unused forest biomass resources based on GT (green ton). Using a forest functions classification map (1 : 25,000), 5th digital forest type map (1 : 25,000), and digital elevation model (DEM), the forest area with a slope of 30° or less and mountain ridges of 70% or less was estimated based on production forest and IV age class or more. The total forest area where unused forest biomass can be produced was estimated to be 1,453,047 ha. Based on GT, the total amount of unused forest biomass potential resources in Korea was estimated to be 117,741,436 tons. By forest type, coniferous forests were estimated to be 48,513,580 tons (41.2%), broad-leaved forests 27,419,391 tons (23.3%), and mixed forests 41,808,465 tons (35.5%). Data from this research analysis can be used as basic data to estimate commercial use of unused forest biomass.

• Journal of the Korean Wood Science and Technology
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• v.43 no.5
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• pp.578-590
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• 2015

The present study examines the influence of slurry composting and biofiltration liquid fertilizer (SCBLF) treatment on the biomass characteristics of yellow poplar, and the optimization of organosolv pretreatment for sugar production. After SCBLF treatment, total exchangeable cation contents of yellow poplar was increased from $3.1g\;kg^{-1}$ to $4.4g\;kg^{-1}$, and as a result, biomass production of yellow poplar was also enhanced by 82.3%. Organosolv pretreatment was conducted with three independent variables: 1) reaction temperature: $133.2^{\circ}C$ to $166.8^{\circ}C$; 2) acid concentration: 0.2% to 1.8%; and 3) reaction time: 1.6 min to 18.4 min. Reaction temperature was the most significant variable in water insoluble solid (WIS) recovery rate. High overall sugar yield was attained from pretreatment conditions approximately 50% of WIS recovery rate, and the highest overall glucose yield (44.0%) was achieved from pretreatment at $140^{\circ}C$ with 1.5% acid concentration for 5 min. Consequently, 21.1% of glucose and 5.8% of xylose were produced from the organosolv pretreatment of SCBLF-treated 8-year-old yellow poplar.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.7
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• pp.1010-1016
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• 2000

Effect on the bio-mass and nutrient yield of Lemna perpusilla Torry was studied at two nutrient loading frequencies. Six polythene sinks ($6{\times}2{\times}0.5m^{3}$ area) randomly allocated to two treatments having three sinks in each treatment. Each sink containing $6{\times}2{\times}0.35m^{3}$ water body, was changed either daily with 12.6 kg anaerobically fermented cattle manure (effluent) or with 76 kg efluent at six-day interval. Media Kjeldhal-N (40 vs. 36 mg/L; p>0.05) and $NH_3$-N (9 vs 7 mg/L; p<0.05) concentration were higher in daily charged sinks than those charged at six-day interval. However, temperature ($28.48{^{\circ}C}\;vs.\;28.60{^{\circ}C}$) and pH (6.82 vs. 6.84) were sinilar in both groups of sinks. Biomass (93 vs. $80g/m^{2}/d$) and crude protein (1.24 vs. $1.11g/m^{2}/d$) yield were non-significantly (p>0.05) higher in the daily charged than 6-d interval charged ponds. However, dry matter (4.52 vs. 4.15%), organic matter (83 vs. 84%), crude protein (31.4 va. 29.6%) and organic carbon (47 vs. 47%) content were similar in both daily and 6-d interval charged ponds. There were no apparent relationships between the crude protein content of Lemna and the media Kjeldhal-N or $NH_3$-N concentration apparently due to saturated level of nutrient (N in particular). It was concluded that with the level of effluent used for two treatments, nutrient-loading frequency had no significant effect on the biomass and protein yield of Lemna. Technique described here can be used for year-round duckweed production from fermented cattle manure for feeding poultry/fish in smallholder production system.

• Journal of Applied Biological Chemistry
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• v.60 no.4
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• pp.333-338
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• 2017

Cellulosic alcohol fermentation has recently gained more attention in the production of ethanol, butanol, and 2,3-butanediol. However, it was revealed that the process had several hurdles, such as, an expensive cost for biomass decomposition to yield fermentable sugars and a production of byproduct lignin. As an alternative for the process through biomass saccharification, the alcohol production through syngas from biomass has been studied. In this study, we reviewed acetogen and its central metabolic pathway, Wood-Ljungdahl route, capable of utilizing syngas. Furthermore, the metabolic engineering strategies of acetogen for bio-alcohol production from syngas was also reviewed with a brief perspective.

• Applied Chemistry for Engineering
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• v.24 no.6
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• pp.579-586
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• 2013

The shortage of fossil fuel and problem of greenhouse gas exhaustion drive the production of biopolymer in a environment-friendly manner. Polyurethane is a polymer formed by reacting an isocyanate (-NCO) with a polyol (-OH) to form urethane link (-NHCOO-). Polyurethane is one of the most widely used polymers in automobile, construction and chemical industries. Two monomers for the polymerization of polyurethane, polyols and isocyanates, can be produced from renewable biomass such as plant oil, cellulose, lignin and etc. Biopolyol production from plant oil has already been implemented in commercial-scale production. In this paper, recent progresses on bio-based approaches on the production of biopolyols, bio-isocyanates and bio-substituent or isocyanate from bio-feedstock are reviewed alongside polymerization and characterization of biopolyurethane for industrial applications.

• Korean Journal of Medicinal Crop Science
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• v.20 no.6
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• pp.479-486
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• 2012

The production of adventitious roots derived from root explant of Echinacea angustifolia and its secondary metabolite content were assessed in different types and levels of auxin. The induction of adventitious roots from root explant cultured in Murashige and Skoog solid medium supplemented with 1.0 mg/L indole -3-butyric acid (IBA) attained highest as 20.87 mg fresh weight and 3.07 mg dry weight per culture but root suspension culture at the same concentration of IBA enhanced biomass production as 3.07 g fresh weight and 0.38 g per culture after 4 weeks in culture. 3.0 mg/L ${\alpha}$-naphthalene acetic acid (NAA) treatment had similar effect on root biomass production as 3.07 g fresh weight and 0.38 g per culture with liquid suspension culture, whereas adventitious roots exposed to over 3.0-5.0 mg/L IBA or 5.0 mg/L NAA were less responsive by reducing the number of adventitious roots and/or changing root morphology such as short and thick. The content of secondary metabolites such as phenolic, flavonoids and total caffeic acid in adventitious roots cultured on MS medium supplemented with 1.0 mg/L IBA were attained highest as 27.20, 9.60. 10.67 mg/g dry weight, respectively. Overall, the best production of root biomass and secondary metabolites were given by 1.0 mg/L IBA.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.3
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• pp.99-106
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• 2016

Our aim was to identify the potential of reed stalk as a raw materials for biomass pellet production. Compared to woody biomass, reed stalk contained significant levels of ash. The holocellulose content of reed stalk was similar to that of larch, but the lignin content of reed stalk was lower than that of larch. In the elemental analysis, chlorine content of reed stalk was much higher than that of larch, and satisfied only the mixed biomass pellet B of European non-woody pellet standards(EN 14961-6). In quantitative analysis of the ash, heavy metals contents of reed stalk satisfied European non-woody pellet standards. Higher heating value of oven-dried reed stalk pellet was slightly lower than that of larch wood pellet. The durability of reed stalk pellet was lower than that of larch wood pellet. The results of this study indicate that reed stalk might be used as a raw material of mixed biomass pellet B.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.4
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• pp.445-451
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• 2012

We developed an age-based spawner-recruit model incorporating environmental variables to forecast stock biomass and recruits of pelagic fish in this study. We applied the model to the Tsushima stock of jack mackerel, which is shared by Korea and Japan. The stock biomass of jack mackerel (Trachurus japonicus) around Korean waters ranged from 141 thousand metric tons (mt) and 728 thousand mt and recruits ranged from 27 thousand mt to 283 thousand mt. We hind-casted the stock biomass to evaluate the model performance and robustness for the period of 1987~2009. It was found that the model has been useful to forecast stock biomass and recruits for the period of the lifespan of fish species. The model is also capable of forecasting the long-term period, assuming a certain climatic regime.