• The Korean Journal of Ecology
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• 제1권2호
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• pp.57-65
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• 1977

The biomass and net production of alder and oak trees was estimated by allometric method. The productivity of the two stands of alder and oak was obviously different judging from the rate of photosynthesis productive structure and vertical distribution of light. The amounts of net photosynthesis under the saturated light were 2.31, 1.42mg $CO_2/dm^2\cdot$hr. in the sun and shade leaves of alder tree and 1.58, 0.84mg $CO_2/dm^2\cdot$hr in that of the oak, respectively. Total annual respiration loss calculated from the respiration measured at $25^{\circ}C$ and the mean air temperature from every 10 days were 13.56ton/ha.yr in the alder stand and 19.83 ton/ha.yr in the oak. The productive structure and the vertical distribution of light in the stand were assumedly more effective to produce dry matter in the oak stand than in the alder. The biiomasses measured in 1975 and 1976 were 51.51 and 56.82 ton/ha in the alder stand and 73.35, 86.77 ton/ha in the oak one, respectively. Annual net production and gross production were 8.56 and 22.12 ton/ha.yr in the alder stand but those were 17.90 and 37.74 ton/ha.yr in the oak stand. The ratios of respiration to gross procution (R/Pg) were prespectively 0.61 and 0.53 inthe alder and oak stands. Efficiencies of solar energy utilizaztion of net production during the growing season(May-Oct.) were 0.67 and 1.40% and those of gross production were 1.72 and 2.94% in the alder and oak stands respectively.

• Elastomers and Composites
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• 제56권3호
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• pp.136-151
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• 2021

Biomass lignin, a waste produced during the paper and bio-ethanol production process, is a cheap material that is available in large quantities. Thus, the interest in the valorization of biomass lignin has been increasing in industrial and academic areas. Over the years, lignin has been predominantly burnt as fuel to run pulping plants. However, less than 2% of the available lignin has been utilized for producing specialty chemicals, such as dispersants, adhesives, surfactants, and other value-added products. The development of value-added lignin-derived co-products should help make second generation biorefineries and the paper industry more profitable by valorizing lignin. Another possible approach towards value-added applications is using lignin as a component in plastics. However, blending lignin with polymers is not simple because the polarity of lignin molecules results in strong self-interactions. Therefore, achieving in-depth insights on lignin characteristics and structure will help in accelerating the development of lignin-based products. Considering the multipurpose characteristics of lignin for producing value-added products, this review will shed light on the potential applications of lignin and lignin-based derivatives on polymeric composite production. Moreover, the challenges in lignin valorization will be addressed.

• Journal of Microbiology and Biotechnology
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• 제28권4호
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• pp.571-578
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• 2018

Biofuel production using lignocellulosic biomass is gaining attention because it can be substituted for fossil fuels without competing with edible resources. However, because Saccharomyces cerevisiae does not have a ${\text\tiny{D}}$-xylose metabolic pathway, oxidoreductase or isomerase pathways must be introduced to utilize ${\text\tiny{D}}$-xylose from lignocellulosic biomass in S. cerevisiae. To elucidate the biochemical properties of xylose isomerase (XI) from Piromyces sp. E2 (PsXI), we determine its crystal structure in complex with substrate mimic glycerol. An amino-acid sequence comparison with other reported XIs and relative activity measurements using five kinds of divalent metal ions confirmed that PsXI belongs to class II XIs. Moreover kinetic analysis of PsXI was also performed using $Mn^{2+}$, the preferred divalent metal ion for PsXI. In addition, the substrate-binding mode of PsXI could be predicted with the substrate mimic glycerol bound to the active site. These studies may provide structural information to enhance ${\text\tiny{D}}$-xylose utilization for biofuel production.

• Korean Chemical Engineering Research
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• 제54권4호
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• pp.519-526
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• 2016

Biomass derived jet fuel is proven as a potential alternative for the currently used fossil oriented energy. The efficient production of jet fuel precursor with special molecular structure is prerequisite in producing biomass derived jet fuel. We synthesized a new jet fuel precursor containing branched $C_{15}$ framework by aldol condensation of furfural (FA) and ethyl levulinate (EL), where the latter of two could be easily produced from lignocellulose by acid catalyzed processes. The highest yield of 56% for target jet fuel precursor could be obtained at the optimal reaction condition (molar ratio of FA/EL of 2, 323 K, 50 min) by using KOH as catalyst. The chemical structure of $C_{15}$ precursor was specified as (3E, 5E)-6-(furan-2-yl)-3-(furan-2-ylmethylene)-4-oxohex-5-enoic acid ($F_2E$). For stabilization, this yellowish solid precursor was hydrogenated at low temperature to obtain C=C bonds saturated product, and the chemical structure was proposed as 4-oxo-6-(tetrahydrofuran-2-yl)-3-(tetrahydrofuran-2-yl)-methyl hexanoic acid ($H-F_2E$). The successful synthesis of the new jet fuel precursors showed the significance that branched jet fuel could be potentially produced from biomass derived FA and EL via fewer steps.

• 한국수산과학회지
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• 제36권4호
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• pp.389-401
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• 2003

The changes in structure and abundance of taxon or species groups in the East Sea ecosystem were compared between pre- and post-Climatic Regime Shift (CRS) occurred in the mid 1970s using an ECOPATH model. Although the East Sea ecosystem consisted of primary producers, primary consumers, secondary consumers and terminal consumers most species groups were classified as secondary consumers. The mean trophic level between pre- and post-CRS increased from 3.09 during the pre-CRS period to 3.28 during the post-CRS period. Total biomass of the species groups in the East Sea ecosystem increased by $9\%$ due to the CRS, and total catch increased by $48\%.$ The most significant differences between pre- and post-CRS models occurred at the mid/high trophic levels occupied by fishes and cephalopods. Relative contribution of the different species groups to the total energy flow was calculated for the trophic level III. As a result, the status by the dominant species in the East Sea ecosystem shifted from cephalopods to walleye pollock due to the CRS. Relative contribution of 5 species, which were commercially important, such as Pacific saury, Pacific sardine, filefish, walleye pollock and sandfish in trophic level III, were also changed due to the CRS. Finally, the CRS turned out to cause large variations in biomass and catch of fisheries resources as well as the status and role of the major species.

• Journal of the Korean Wood Science and Technology
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• 제34권4호
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• pp.66-75
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• 2006

충북 월악산 북동 사면 지역(해발 380 m)에서 24년생 잣나무 인공림의 바이오매스와 에너지량을 조사한 결과, 잣나무림의 바이오매스는 줄기부 26.6 ton/ha, 수피부 4.3 ton/ha, 1년생 가지 0.2 ton/ha, 가지부 8.6 ton/ha, 고사지 1.5 ton/ha, 당년생 잎 1.3 ton/ha, 전년생 잎 6.1 ton/ha로서 고사지를 제외한 지상부 전체는 47.0 ton/ha으로 나타났다. 또한 연간 순생산량은 줄기부 3.0 ton/ha/yr, 수피부 0.4 ton/ha/yr, 1년생 가지 0.2 ton/ha/yr, 가지부 1.1 ton/ha/yr, 당년생 잎 1.3 ton/ha/yr이며, 지상부 합계는 6.0 ton/ha/yr로 추정되었다. 이것을 열 에너지량으로 환산하면 지상부 전체의 에너지량은 1,028 GJ/ha, 연간 에너지 고정량(지상부)은 133 GJ/ha/yr로 나타났다. 한편, 잣나무림의 엽면적 지수는 20.2로 나타났다.

• Journal of Plant Biology
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• 제28권2호
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• pp.119-126
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• 1985

Sargassum confusum을 대상으로 동해안 오호리 지역에서 1983년 3월 부더 1984년 4월까지 이 종의 생장 및 일차생산력을 조사하였다. S. confusum은 2월에 생장하기 시작하여 여름에 최대생장을 나타낸 후 빠른 속도로 쇠퇴하는 생육주기를 가진다. 생식활동은 6월에 주로 이루어 진다. 이러한 생장양상은 수온과 밀접한 관제를 갖는다. 최대성장율은 5월의 1.3cm/day이며 최대길이는 8월의 120cm이다. 산소명암병법으로 측정된 S. confusum의 일순생산력은 6월에 11.2 gC/dry wt/day이며 이를 기초로 추정한 연생산력은 745 gC/$m^2$/yr이다. 한편 현존량의 변화에만 의존하여 추정된 연생산력은 745 gC/$m^2$/yr로서 탈락에 의한 손실이 약 60%에 달하고 있다.

• 임산에너지
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• 제17권1호
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• pp.1-7
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• 1998

충북 월악산 지역 24년생 낙엽송 조림지의 생산력을 조사하기 위해 8본의 표본목을 벌목하여 부위별(줄기, 가지, 잎)로 생중량을 측정하고 생산구조를 조사한 결과를 요약하면 다음과 같다. (1) 낙엽송의 광합성부는 지상 13m에서 시작되며, 수관의 최대광합성층은 15-16m에서 나타났다. (2) 지상부의 현존량은 줄기 160.75ton/ha(86.3%), 가지 18.42ton/ha(9.9%), 잎 7.08ton/ha(3.8%)이었고 전체 지상부의 현존량은 186.25ton/ha이었다. (3) 연순생산량은 줄기 10.17ton/ha/yr, 가지 1.47ton/ha/yr, 잎 0.54ton/ha/yr이었으며, 전체 순생산량은 12.17ton/ha/yr로 나타났다. 순생산량에서 전체에 대한 각 기관별 비율은 줄기 83.5%, 가지 12.0%, 잎 4.5%로서 가지와 잎의 부위가 낮은 비율을 보이고 있었다.

• Ocean and Polar Research
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• 제33권4호
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• pp.457-472
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• 2011

To elucidate the trophic role of heterotrophic nano- and microplankton (HNMP), we investigated their biomass, community structure, and herbivory in three different water masses, namely, south of Polar Front (SPF), Polar Front Zone (PFZ), the Sub-Antarcitc Front (SAF) in the Drake Passage in the Southern Ocean, during the austral summer in 2002. We observed a spatial difference in the relative importance of the dominant HNMP community in these water masses. Ciliates accounted for 34.7% of the total biomass on an average in the SPF where the concentration of chlorophyll-a was low with the dominance of pico- and nanophytoplankton. Moreover, the importance of ciliates declined from the SPF to the SAF. In contrast, heterotrophic dinoflagellates (HDFs) were the most dominant grazers in the PFZ where the concentration of chlorophyll-a was high with the dominance of net phytoplankton. HNMP biomass ranged from 321.9 to 751.4 $mgCm^{-2}$ and was highest in the PFZ and lowest in the SPF. This result implies that the spatial dynamic of HNMP biomass and community was significantly influenced by the composition and concentration of phytoplankton as a food source. On an average, 75.6%, 94.5%, and 78.9% of the phytoplankton production were consumed by HNMP in the SPF, PFZ, and SAF, respectively. The proportion of phytoplankton grazed by HNMP was largely determined by the composition and biomass of HNMP, as well as the composition of phytoplankton. However, the herbivory of HNMP was one of the most important loss processes affecting the biomass and composition of phytoplankton particularly in the PFZ. Our results suggest that the bulk of the photosynthetically fixed carbon was likely reprocessed by HNMP rather than contributing to the vertical flux in Drake Passage during the austral summer in 2002.

• 한국환경복원기술학회지
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• 제10권5호
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• pp.20-30
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• 2007

Environmental Conservation Value Assessment Map (ECVAM) is the class map to divide the national land into conservation areas and development areas based on legal and ecological assessment criteria. It contributes to enhancements of the efficiency and the scientificity when framing a policy in various fields including the environment. However, it is impossible to understand the multiphase vegetation structure as data on judging the national forest class in ECVAM are restricted to areal information of Ecological Nature Status, Degree of Green Naturality and Forest Map. This point drops the reliability of ECVAM. Therefore we constructed vegetation information using LiDAR (Light Detection And Raging) technology. We generated Biomass Class Maps as final results of this study, to introduce the new forest assessment criterion in ECVAM that alternates or makes up for existing forest assessment criteria. And then, we compared these with Forest Map and Landsat TM NDVI image. As a result, biomass classes are generally higher than stand age classes and DBH classes of Vegetation Map, and lower than NDVI of Landsat TM image because of the difference of time on data construction. However distributions between these classes are mostly similar. Therefore we estimates that it is possible to apply the biomass item to the new forest assessment criterion of ECVAM. The introduction of the biomass in ECVAM makes it useful to detect the vegetation succession, to adjust the class of the changed zone since the production of Vegetation Map and to rectify the class error of Vegetation Map because variations on tree heights, forest area, gaps between trees, vegetation vitality and so on are acquired as interim findings in process of computing biomass.