• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.3
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• pp.186-195
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• 2018

A field study was conducted over a 3-year period from 2014 to 2016 in the central plain area, Suwon, Korea, 1) to compare the biomass production between machine-transplanted and water-broadcast seeded silage rice and 2) to elucidate the growth factors that affect the difference in biomass production between the two cultivation practices. The heading date for the water-broadcast seeded silage rice was September 11-18, which was delayed by 11-17 days when compared to that for the machine-transplanted silage rice. On average, water-broadcast seeded silage rice had a shorter plant height, more panicles per area, and a greater biomass production because of the increased straw dry weight. However, the difference in dry weight of each plant organ between the two cultivation practices exhibited yearly variation. When the data were pooled across experimental years, cultivation practices, and varieties, biomass production was highly positively correlated with straw dry weight but not with panicle dry weight. When the ratio of water-broadcast seeding to machine-transplanting was analyzed, total dry weight and straw dry weight were positively associated with each other, whereas no relationship was found between total dry weight and panicle dry weight. Despite that water-broadcast seeded silage rice produced more panicles per area than machine-transplanted silage rice, the two cultivation practices had a similar dry weight per culm. Therefore, we conclude that the silage rice from the water-broadcast seeding, compared to the machine-transplanting, produced more biomass because of the combination of the increased panicle number per area and a similar dry weight per culm. These results suggest that silage rice could be produced through water-broadcast seeding to increase biomass production with low labor and cost input.

• New & Renewable Energy
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• v.19 no.4
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• pp.11-19
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• 2023

Levulinic acid (LA) derived from cellulosic biomass, serves a crucial intermediate that can be used in various chemical conversions. This study focused on optimizing the production of LA using two types of pretreated rice husk (de-ashed and delignificated cellulosic biomass) in a batch reaction system through catalytic conversion with sulfuric acid. To determine the optimal conditions, the conversions of glucose and α-cellulose were examined to compare the effects of pretreatment on the rice husk. The experimental parameters covered a broad spectrum, including temperatures ranging from 140℃ to 200℃, a reaction time was up to 600 minutes, and a substrate to catalyst (acid solution) ratio of 100 g/L. The highest LA yield was 44.8%, achieved from de-ashed rice husk with 3.0 wt.% of sulfuric acid at 180℃ and with a reaction time of 180 minutes. In the case of the delignificated rice husk, a LA yield of 43.6% was obtained with 3.0 wt.% of sulfuric acid at 200℃ and with reaction time of 30 minutes.

• Journal of Animal Science and Technology
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• v.60 no.11
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• pp.26.1-26.9
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• 2018

Background: This experiment aimed at assessing polyphenol-rich plant biomass to use in complete feed making for the feeding of ruminants. Methods: An in vitro ruminal evaluation of complete blocks (CFB) with (Acacia nilotica, Ziziphus nummularia leaves) and without (Vigna sinensis hay) polyphenol rich plant leaves was conducted by applying Menke's in vitro gas production (IVGP) technique. A total of six substrates, viz. three forages and three CFBs were subjected to in vitro ruminal fermentation in glass syringes to assess gas and methane production, substrate degradability, and rumen fermentation metabolites. Results: Total polyphenol content (g/Kg) was 163 in A. nilotica compared to 52.5 in Z. nummularia with a contrasting difference in tannin fractions, higher hydrolysable tannins (HT) in the former (140.1 vs 2.8) and higher condensed (CT) tannins in the later (28.3 vs 7.9). The potential gas production was lower with a higher lag phase (L) in CT containing Z. nummularia and the component feed block. A. nilotica alone and as a constituent of CFB produced higher total gas but with lower methane while the partitioning factor (PF) was higher in Z. nummularia and its CFB. Substrate digestibility (both DM and OM) was lower (P < 0.001) in Z. nummularia compared to other forages and CFBs. The fermentation metabolites showed a different pattern for forages and their CFBs. The forages showed higher TCA precipitable N and lower acetate: propionate ratio in Z. nummularia while the related trend was found in CFB with V. sinensis. Total volatile fatty acid concentration was higher (P < 0.001) in A. nilotica leaves than V. sinensis hay and Z. nummularia leaves. It has implication on widening the forage resources and providing opportunity to use forage biomass rich in polyphenolic constituents in judicious proportion for reducing methane and enhancing green livestock production. Conclusion: Above all, higher substrate degradability, propionate production, lower methanogenesis in CFB with A. nilotica leaves may be considered useful. Nevertheless, CFB with Z. nummularia also proved its usefulness with higher TCA precipitable N and PF. It has implication on widening the forage resources and providing opportunity to use polyphenol-rich forage biomass for reducing methane and enhancing green livestock production.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.1
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• pp.54-61
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• 2007

The influences of pH were investigated for anaerobic hydrogen gas production under the constant pH condition ranged from pH 3 to 10. Carbon dioxide and hydrogen gas were main components of the gas but methane was not detected in the produced gas when sucrose was added in enrichment medium. When the modified Gompartz equation was applied for the statistical analysis of experimental data, a hydrogen production potential and maximum gas production rate at pH 5 were 1,182 mL and 112.46 mL/g dry wt biomass/hr. The hydrogen conversion ratio was 22.56%. The butyrate/acetate ratios at pH 5 and pH 6 are 1.63 and 0.38. Higher butyrate/acetate ratio produced more hydrogen gas generation. The Haldane equation model was used to find the optimum pH and fitted well with the experimental data$(r^2=0.98)$. The optimum pH and specific hydrogen production were 5.5 and 119.61 mL/g VSS/h.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.2
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• pp.125-132
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• 2011

This paper describes current status and future prospects of the mass production of microalgae biomass. Microalgae have attracted considerable attention since they not only effectively fix $CO_2$ gas during their metabolic process but also have the great potential to be utilized for producing valuable substances as a kind of efficient light-harvesting cell factories. In this review, we outline various types of photobioreactors employed for mass production of biomass by culturing microalgae in a well controlled way and give an overview about the present state of affairs, both domestic and international, in the field of the microalgal culturing technologies.

• Journal of Microbiology and Biotechnology
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• v.20 no.3
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• pp.525-531
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• 2010

This work was aimed at utilizing rice bran as a substrate for $\beta$-carotene production by Rhodotorula glutinis DM 28 under optimized conditions of solid-state fermentation. The biomass and $\beta$-carotene content of Rhodotorula glutinis DM 28 grown on rice bran as a sole substrate under solid-state fermentation were 54 g/kg rice bran and 1.65 mg/kg rice bran, respectively. Its biomass and $\beta$-carotene content, however, could be improved by 60% and 30%, respectively, using the Central Composite Design for the optimization of its cultivation conditions. The optimized conditions obtained were a pH of 5, a moisture content of 70% (w/w), and a carbon-to-nitrogen ratio of 4. Under these conditions, rice bran containing R. glutinis DM 28 had nutritional values of $\beta$-carotene, protein, and fat higher than those of rice bran alone. Yeast-grown rice bran could be suitable, therefore, to use as a $\beta$-carotene-enriched supplement in animal feeds.

• Korean Journal of Microbiology
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• v.21 no.3
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• pp.163-169
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• 1983

Effects of temperature on the gorwth characteristics and the chemical composition of pseudomonas cells grown under glucose-or methanol-utilizing continuous culture were studied. In a glucose-utilizing continuous culture, optimum dilution rate, agitation, pH, and temperature, for the higher biomass yield were $0.45hr^-$, 7000rpm, pH 7.5, and $30^{\circ}C$, respectively. But in a methanol-utilizing continuous culture, they were $0.125hr^-$, 600rpm, pH 8, and $30^{\circ}C$, respectively. In methanol-utilizing continuous culture, the maximum production rate of the cells was 1.48g, dry wt./1/hr at a dilution rate of $0.45hr^-$, and the cell yield was 0.46g. dry wt./g. glucose. In the methanol-utilizaing continuous culture, the maximum production rate of the cells was 0.33 7g. dry wt./1/hr. at a dilution rate of $0.125hr^-$ and the cell yield was 0.44g dry cell/g. methanol. The contents of protein of the cells increase with the increase ingrowing temperature (from 15 to $30^{\circ}C$), more or less, while the contents of RNA nad carbohydrate of the cells decreased. However, DNA contents of cells growth under the various temperature ranges didn't change. As the temeprature of cultivation rises at a constant dilution rate, the efficiency of RNA in protein synthesis was increased, showing the decreases in the ratio of RNA to protein.

• Journal of Korean Society of Forest Science
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• v.70 no.1
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• pp.91-102
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• 1985

Growth and biomass production of natural stands of Quercus variabilis in relation to tree density were studied to obtain basic guide lines for future tending operation. Two natural stands of Quercus variabilis located at 900m (A stand: 6,600trees/ha, $15.84m^2/ha$, $\frac{19}{17-20}$) and 800m (B stand: 4,300trees/ha, $16.65m^2/ha$, $\frac{20}{17-21}$) elevation in Sancheong, Kyongnam Province were selected for the comparative study and following results were obtained through a sample plot method. After diameter of individual trees in the sample plots was measured, twelve average trees from each diameter class were cut felled to measure dry weight of $W_S$, $W_B$, $W_L$, $W_{Ba}$, and standing biomass and biomass production rates by a allometrior regressions related to $D^2H$. Vertical distribution of leaves along the stems indicated that photosynthesis was carried out 2.2m above the ground in Stand A and 1.2m in Stand B. Maximum photosynthesis was located 4.2m and 6.2m above the ground in Stand A and B, respectively. Leaf area index was 4.25ha/ha for Stand A, and 3.89ha/ha for Stand B. Above-ground standing biomass was 49.51 ton/ha for Stand A and 59.20 ton/ha and net annual production was 6.75 ton/ha/yr. for Stand A and 8.99 ton/ha/yr. for Stand B. The ratio of net annual production to standing biomass was 17.5% for Stand A and 16.7% for Stand B. Net assimilation rate was 2.75kg/kg/yr. for Stand A and 3.58kg/kg/yr. for Stand B. Stem wood production rate was 1.46kg/kg/yr. for Stand A and 2.09kg/kg/yr. for Stand B. Bark production rate was 0.60 kg/kg/yr. for Stand A and 0.34kg/kg/yr. for Stand B. Above data indicated that Stand B utilized growing spaces and sites more efficiently than Stand A. It is concluded chat productivity of natural stands of Quercus variabilis can be enhanced through optimization of basal areas and number of tree per hectare and that sound management of natural oak stands should be based on systematic sampling of the area for periodic productivity estimation.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.509.2-509
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• 1986

Owing to the growing interest in the production of fuels and chemicals from biomass the well-know butanol-acetone fermentation as carried out by Clostridium acetobutylicum has been intensely studied again in recent years. Several solvent-yielding fermentation processes were established which are operated by using batch cultures or continuous cultures. 1 could be shown that under conditions of phosphate limitation an asporogenous mutant of C. acetobutylicum establishes itself in a chemostat which produces the solvents continuously. Attempts have been made to change the butanol/acetone ratio in favor of butanol production. A corresponding shift of the product spectrum can be achieved by carbon monoxide addition to the head space of the fermentation (B.H. Kim et al., App. Envioron. Microbiol. 48, 764-770 1984) or by iron limitation. Progress has been made in understanding the mechanism underlying the shift from acid to solvent prodcction. Experimental results are in agreement with the view that intracellular accumulation of acetic and butyric acid results in a shortage of phosphate and coenzyme A. This shortage may serve then as signal for the synthesis of the enzymes involved in the formation of acetone and butanol.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.168-168
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• 2022

According to the 5th Climate Change Report, global average temperature in 2081~2100 will increase 1.8℃ based on RCP 4.5 and 3.7℃ based on RCP 8.5 from the current climate value (IPCC Working Group I AR5). As temperature is expected to increase due to global warming and the intensity and frequency of rainfall are expected to increase, damage to crops is expected, and countermeasures must be taken. This study intends to evaluate rice growth in terms of nitrogen utilization efficiency according to future climate change conditions. In this experiment, Oryza sativa cv. Shindongjin were planted at the SPAR facility of the NICS in Wanju-gun, Jeollabuk-do on June 10, and were planted and grown according to the standard cultivation method. Cultivation conditions are high temperature, high CO₂ (current temperature+4.7℃·CO₂ 800ppm), high temperature (current temperature+4.7℃·CO₂ 400ppm), current climate (current tempreture·CO₂ 400 ppm). Nitrogen was varied as 0, 9, 18 kg/10a. The N content and C/N ratio of all rice leaves, stems, and seeds increased at high temperature, and the N content and C/N ratio decreased under high temperature and high CO₂ conditions com pared to high temperature. Compared to the current climate, NUE increases by about 8% under high temperature and high CO₂ conditions and by about 2% under high temperature conditions. This seems to be because the increase in temperature and CO₂ induced the increase in biomass. ANUE related to yield decreased by about 70% compared to the current climate under high temperature conditions, and decreased by about 45% at high temperature and high CO₂, showing a tendency to decrease compared to high temperature. This appears to be due to reduced fertility and poor ripening due to high temperature stress. However, as the nitrogen increased, the number of ears and the number of grains increased, slightly offsetting the production reduction factor.