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The alkaline hydrothermal separation of cellulose is a crucial step in biofuel generation, wherein black liquor containing lignin and alkali is produced as a by-product. This study explored the reaction mechanism of the residual alkali during the activation process. In this reaction, the impregnated K reagent exhibited unusual behavior owing to its bonding with the lignin structure, which was confirmed by the K 2p peak shift in x-ray photoelectron spectra. This behavior resulted in the formation of a microporous and mesoporous substance with a high surface area of 2146 m2 g−1 without requiring additional chemical reagents. Furthermore, the activated carbon derived from black liquor possessed outstanding properties, allowing its use in supercapacitors. This study demonstrates that giant miscanthus-derived black liquor can be used as an activated carbon precursor for application in electric double-layer capacitors owing to its superior electrochemical capabilities.

Giant miscanthus (GM) is an Asian grass that can produce biomass in high yields per land area. It can be used as a cathode material in lithium sulfur (Li/S) batteries. Giant-miscanthus-derived activated carbon (GMAC) is prepared via carbonization of GM followed by KOH activation. It is prepared with a large amount of KOH, and thus contained more defects but had a highly porous structure and graphitic cluster lattice. GMAC has a large specific surface area of 3327 m2/g and a large total pore volume of 1.86 cm3/g. The pore volume served as a storage space for the retention of polysulfides, thereby inhibiting the shuttle effect. When a GMAC–sulfur composite cathode is tested in a Li/S battery, an initial discharge capacity of 1148 mAh/g can be attained at 0.1 C. In a cyclic charge–discharge experiment at 1 C, discharge capacities of 529 mAh/g and 248 mAh/g are observed in the first and 200th cycles, respectively.

Miscanthus (Geodae-Uksae in Korean, GU) is a promising source of biomass for biosugar production due to its superior mass yield and minimal need for nitrogen fertilizer and herbicides. In this study, the biomass productivity, chemical composition, and physical properties of Miscanthus were investigated for two harvest dates. The total biomass of early harvest GU (EH-GU; 20.1 t DM/ha) was greater than that of the delayed-harvest GU (DH-GU; 18.0 t DM/ha). There was no noticeable difference in the carbohydrate content between the EH-GU and DH-GU, while the lignin content remarkable decreased after pretreatment. The enzymatic conversion rates of GU to biosugar increased after pretreatment, to approximately 86 to 90%. After enzymatic hydrolysis, 381 g and 147 g of glucose and xylose were produced, respectively. Consequently, 528 g of biosugar was obtained from 1 kg of EH-GU. Determining the optimal harvest date of Miscanthus has enabled a more efficient enzymatic hydrolysis and higher biosugar yields.

Pretreatment to improve the enzymatic digestibility of highly crystallized lignocellulosic biomass is essential in biorefinery processes. This study investigates the combination of lignocellulose pretreatment with continuous alkaline single-screw extrusion and ultrasonication for biosugar production. Miscanthus sacchariflorus was used because it is a promising bioenergy crop. The results show that ultrasonication with continuous alkaline pretreatment increased the enzymatic digestibility of carbohydrates and reduced the use of chemicals during pretreatment. An hour of ultrasonication following 0.2 M NaOH (2.25 mol-NaOH/kg-biomass) continuous alkaline pretreatment resulted in a 6.7% increase in total biosugar production (83.1% of theoretical yield), a decrease of up to 26.1% in chemical usage, and a 17.0% increase in lignin removal compared with the case without ultrasonication. The developed method can be considered an effective and eco-friendly approach to the production of bio-based materials.

M. × giganteus, a hybrid of tetraploid M. sacchariflorus and diploid M. sinensis, is a good bioenergy crop because of its high biomass yield and non-invasiveness in non-native countries. However, this species has a single cultivar that was derived from the same clone, and would, therefore, have higher susceptibility to biotic and abiotic stress. To breed M. × giganteus cultivars, we developed an interspecific crossing method and assessed the breeding efficiency of this method. From the hybrid seeds of 14 crossing combinations, we obtained 323 young plants, of which 290 plants became necrotized during the seedling stage. Of the surviving 33 plants, 12 were assumed to be triploid based on their stomatal length, relative fluorescence intensity values, rhizome elongation, and growth habit, which were similar to those of ‘legacy M. × giganteus’ but were different from M. sacchariflorus and M. sinensis. In the first planting year, four plants headed during the first 10 days of October. Pollen grain size in some hybrid plants was not different from that in the fertile, diploid M. sinensis. The percentage of abnormal pollen and the coefficient of variation of pollen size in all hybrid plants and legacy M. × giganteus were different from those in tetraploid M. sacchariflorus and diploid M. sinensis. At 10 days after flowering, ovules were viable in diploid M. sinensis and tetraploid M. sacchariflorus but aborted in the interspecific hybrid and legacy M. × giganteus. Owing to its sterility, the newly bred Miscanthus interspecific hybrid has low invasion potential, posing minimal threat to the native flora, and is, therefore, suitable for cultivation in non-native countries. These results can be applied to future Miscanthus breeding programs designed to secure the genetic diversity of M. × giganteus and to develop a range of Miscanthus cultivars that can produce high biomass yield under diverse biotic and/or abiotic conditions.

Tetralocular type of Brassica rapa has a wide silique, containing more seeds than in the bilocular type. To elucidate physiological and molecular mechanisms underlying seed development of the tetralocular silique, we defined the embryo development of tetralocular B. rapa (‘Sarsyun’) from 10 to 49 days after flowering (DAF) and measured total C, soluble sugars, lipid content, and changes in genome-wide transcript abundance during the seed filling phase. Hexoses transiently accumulated in young seeds at higher levels than sucrose, whereas a high sucrose level was observed in mature seeds. In contrast, the silique wall exhibited high levels of total soluble sugars at 14–35 DAF, but their levels dissipated after 35 DAF. The gradual decrease in total soluble sugars in the silique wall was likely correlated with seed lipid accumulation. Lipid accumulation in seeds began at approximately 21 DAF, reaching the maximum (45% dry matter) at 35–42 DAF. High lipid accumulation between 28 and 35 DAF was strongly correlated with a rapid increase in seed dry weight. In parallel, 34,423 contigs from four different developing seeds (21, 28, 35, and 42 DAF) were analyzed for transcriptional profiling of the developing seeds. Most genes involved in seed photosynthesis and carbohydrate metabolism were highly expressed at 21 or 28 DAF and were subsequently downregulated. The expression of genes coding for oleosins and fatty acid synthesis and elongation markedly increased at 28 DAF through 35 DAF, respectively, remaining high thereafter. The expression of major storage protein genes increased at 28 or 35 DAF. The accumulation of seed storage compounds in tetralocular B. rapa was highly dependent on photoassimilates in seeds and the silique wall. Transcriptional changes and transcript abundances in relation to seed storage compounds differed across seed development stages. Overall, dynamic changes to transcript abundance of most genes in relation to seed storage products occurred between 28 and 35 DAF. We proposed that the tetralocular ovary in B. rapa may be a useful trait for improving seed yield and yield contributing traits in Brassica species.

In enzymatic hydrolysis, high lignocellulose loadings are required to obtain high sugar titers. However, the high solids loadings limit enzymatic hydrolysis. In this study, to overcome this limitation, the promoting and synergistic effects of the accessory agents of hemicellulase (i.e., Cellic HTec2) and polyethylene glycol (PEG) 8000 were investigated in the enzymatic hydrolysis of hydrothermally pretreated empty fruit bunches (EFBs). After the optimal addition of Cellic HTec2 and PEG, high enzymatic digestion of the pretreated EFBs was achieved owing to their synergistic effects, even at high solids loadings. For example, the enzymatic digestibility of pretreated EFBs at a 21.7% (w/v) solids loading with 10 FPU of Cellic CTec2/g glucan reached 72.5% when 2.7 mg of Cellic HTec2/g glucan and 62.5 mg of PEG/g glucan were used as the accessory agents. These results suggested that the optimal addition of accessory agents is effective for the enhanced hydrolysis of lignocellulose using even a commercial cellulase preparation.

Application of rapeseed meal as organic fertilizer improves soil environment and crop productivity by supplying the nutrients. This study aimed to investigate the optimal application levels of rapeseed meal for rice cultivation. Application of rapeseed meal increased the height of rice plants by about 5–10% compared to the control, and its application at a rate of 50, 100, 200, and 300 kg/0.1 ha increased the nitrogen content in rice leaves at 30 days after treatment by 107.3, 110.4, 114.7, and 114.7%, respectively, compared to the control. In treatments with a mixture of chemical fertilizer and rapeseed meal (50, 100, 200, and 300 kg/0.1 ha), the nitrogen content in rice leaves increased by 105.1–107.7% compared to that in the control; there was no significant difference between the treatment with chemical fertilizer only and that with the mixture of chemical fertilizer and rapeseed meal. The chemical properties of soil treated with rapeseed meal at 200 and 300 kg/0.1 ha or with the mixture of 200 kg/0.1 ha rapeseed meal and chemical fertilizer (1/2 level) showed that nitrate and ammonium increased in treated soils as compared to untreated soil. The yield and yield components were positively correlated with the application levels of rapeseed meal and the mixture of rapeseed meal and chemical fertilizer. The application of rapeseed meal at 100–200 kg/0.1 ha is considered optimal, and efficient application of nitrogen is achieved by mixing chemical fertilizer (11 kg/0.1 ha) with rapeseed meal (100–200 kg/0.1 ha).

Even though industrial yeast strains exhibit numerous advantageous traits for the production of bioethanol, their genetic manipulation has been limited. This study demonstrates that an industrial polyploidy Saccharomyces cerevisiae JHS200 can be engineered through Cas9 (CRISPR associated protein 9)-based genome editing. Specifically, we generated auxotrophic mutants and introduced a xylose metabolic pathway into the auxotrophic mutants. As expected, the engineered strain (JX123) enhanced ethanol production from cellulosic hydrolysates as compared to other engineered haploid strains. However, the JX123 strain produced substantial amounts of xylitol as a by-product during xylose fermentation. Hypothesizing that the xylitol accumulation might be caused by intracellular redox imbalance from cofactor difference, the NADH oxidase from Lactococcus lactis was introduced into the JX123 strain. The resulting strain (JX123_noxE) not only produced more ethanol, but also produced xylitol less than the JX123 strain. These results suggest that industrial polyploidy yeast can be modified for producing biofuels and chemicals.

In this study, highly biocompatible three-dimensional hierarchically porous activated carbon from the low-cost silver grass (Miscanthus sacchariflorus) has been fabricated through a facile carbonization approach and tested it as bioanode in microbial fuel cell (MFC) using Escherichia coli as biocatalyst. This silver grass-derived activated carbon (SGAC) exhibited an unprecedented specific surface area of 3027 m2 g−1 with the coexistence of several micro-, meso-, and macropores. The synergistic effect from pore structure (macropores — hosting E. coli to form biofilm and facilitates internal mass transfer; mesopores — favors fast electron transfer; and micropores — promotes nutrient transport to the biofilm) with very high surface area facilitates excellent extracellular electron transfer (EET) between the anode and biofilm which resulted in higher power output of 963 mW cm−2. Based on superior biocompatibility, low cost, environment-friendliness, and facile fabrication, the proposed SGAC bioanode could have a great potential for high-performance and cost-effective sustainable MFCs.

The use of rapeseed (Brassica napus L.) or leaf mustard (Brassica juncea L. Czern) meal or both as organic fertilizer not only improves the soil environment and crop productivity by supplying nutrients but also has nematicidal effects. This study aimed to establish the optimal application levels of rapeseed and leaf mustard meal for stronger nematode control in tomato. Tomato is one of the most important solanaceous crops which is severely damaged by nematodes. At first, meal (120 g of varying mixing ratios of rapeseed and leaf mustard meal) was mixed with sterilized soil (1 kg). The optimal ratio of rapeseed:leaf mustard meal for effective nematode control was 20:100 g/kg of soil. Progoitrin and gluconapin were the most abundant glucosinolates found in rapeseed meal, while sinigrin was the most abundant in leaf mustard meal. The amount of sinigrin increased if the leaf mustard meal proportion increased in the meal mixture. Although the content of sinigrin in optimal ratio mixture of rapeseed and leaf mustard meal is lower than only leaf mustard meal, it is presumed that nematocidal effects of the mixture are better than that of the single component due to the high contents of progoitrin and gluconapin. So, we propose that rapeseed and leaf mustard meal mixture at an appropriate ratio can be used as an environmentally friendly nematocide.

Background With a growing market for functional foods, the nutraceutical properties of hemp sprouts have been investigated in recent studies. However, commercial mass production methods have yet to be developed. This study aimed to identify seed sizes suitable for segregating ripe seeds, which would improve the low germination rate in the high seed densities used in commercial hemp sprout production. Results Seeds ranging in size from 2.80 to 3.3 mm, collected by sieving, were the most suitable for sprouting, based on the distribution rate (74.9%) and germination rate (70.0%) at a low seed density (0.016 grains mm-2 ). Seed segregation by sinking the seeds in 70% ethanol after 2 h or more of water infiltration generated high germination rates of 86.3% to 94.3% at low seed density, compared to a 64.0% germination rate in non-segregated seeds. The hemp seed germination rate decreased geometrically with increasing sowing density. The germination rate with a high seed density (0.29 grains mm-2 ) was increased from 19.9% when seeds were not mixed with sand to 58.7% when mixed with sand in a 3:1 ratio. The sprouting yield significantly increased from 1.64 kg kg-1 when seeds were not mixed with sand to 9.55 kg kg-1 in seeds germinating when mixed with sand. Delta-9-tetrahydrocannabinol was not detected in hemp sprout. Conclusion The production of hemp sprouts may be improved by identifying suitable seed sizes, segregating ripe seeds, and germinating seeds mixed with sand. This can be used in the commercial production of hemp sprouts. The sprouts were also found to be safe and without hallucinogenic effects. © 2020 Society of Chemical Industry.

Miscanthus are perennial rhizomatous grasses and considered as an ideal cellulosic bioenergy crop. Recently, it was reported that Miscanthus was damaged by the larvae of rice stem borer, Chilo suppressalis Walker, one of the most destructive pests of rice in Korea since the 1960s. This study was thus conducted to evaluate the insecticidal effects against rice stem borer in the Miscanthus cultivation fields for two years. The experiment consisted of four chemical agent plots, one environment-friendly agent plot, and untreated plot. Untreated plot showed significantly high damage of 50%, while Buprofezin·Tebufenozide and Carbosulfan·Methoxyfenozide treatment plots showed low damage rate of 2% with low larvae density of 1 and 2.3 larvae m−2, respectively. Damage rates of Tebufenozide, ChlorantraniliproleIndoxacarb, and environment-friendly agent(MatrineWood vinegar solution) were 15, 26, and 18%, respectively, which were lower than that of untreated plot but higher than those of Buprofezin·Tebufenozide and Carbosulfan·Methoxyfenozide. In conclusion, rice insecticides were effective against rice stem borer in Miscanthus field. In particular, the treatments with Buprofezin·Tebufenozide and Carbosulfan·Methoxyfenozide showed excellent control effects with control value of 93.3 and 95.2. However, further studies with different types of insecticides should be carried out for the selection of insecticides with more effective control of rice stem borer.

Process wastewater (black liquor, BL) is one of the critical targets for reducing operational costs in alkaline pretreatment for bioethanol production. However, no previous study has evaluated the recycling or reuse of BL at the pilot scale. Thus, in this study, the feasibility of recycling pretreatment-generated BL for further pretreatment processes was investigated. The pretreatment was conducted with a twin-screw extrusion system under a barrel temperature of 100 °C, 0.6 M NaOH, biomass feeding of 5.5 kg/h, liquid feeding of 33 L/h, screw speed of 80 rpm, and residence time of 8 min. After enzymatic hydrolysis, fermentable glucose was produced at 313.6 g/kg biomass. In the subsequent pretreatment with the first- and second-generated BL, the converted glucose concentrations slightly decreased to 303.0 and 261.1 g /kg biomass, respectively. Notably, glucose yield from the biomass pretreated with the first BL was 96.7% of that treated with 0.6 M NaOH; thus, 69.7% of NaOH could be saved. In addition, the main BL factors contributing to lower pretreatment efficacy and saccharification yield were identified to be high viscosity and high lignin content. Thus, these results on BL recycling at the pilot scale might contribute to the development of new processes for bioethanol production from lignocellulosic biomass.

Lignin nano-/microstructures are widely employed for agricultural drug delivery and heavy metal removal from wastewater, and facile low-cost methods of their large-scale production are therefore highly sought after. Herein, uniform-morphology polydisperse lignin microspheres were directly extracted from black liquor by lowering its pH to4 followed by hydrothermal treatment and featured several lignin-typical characteristics, e.g., functional groups, thermal stability, amorphousness, and monolignol units. It was assumed that lignin rearranged and assembled into microspheres of various size, shape, and uniformity depending on pH, temperature, and hydrothermal treatment time. Lignin microsphere extraction efficiency was estimated as 15.87-21.62 g L

The development of rapeseed cultivars (Brassica napus L.) with high oleic acid and low linolenic acid is highly desirable for food and industrial applications. In this study, the Korean rapeseed cultivar Tamla was used for ethyl methanesulfonate (EMS)-induced mutagenesis and seed oils were screened up to generation M7 for high oleate mutants. Two mutant populations (M7) with an average of approximately 76% oleic acid content were isolated. Yield components between two mutant populations and untreated Tamla plants were not substantially different, although the mutants in the vegetative stage were slightly smaller in size than Tamla. Genomic analyses of six fatty acid desaturase (four FAD2 and two FAD6) genes revealed that the elevated oleic acid content in the mutants is the result of single gene mutations. Changes in DNA sequence were observed in two genes out of six fatty acid desaturase (four FAD2 and two FAD6). FAD2-2 exhibited a 2-bp deletion in the upstream region of the gene in the two mutants, resulting in a severely truncated polypeptide (57 aa instead of 469 aa), while six point mutations in the other gene did not result in changes in the amino acid sequence. Based on these results, FAD2-2, an endoplasmic reticulum (ER) oleic acid desaturase, is affected in the mutants, resulting in a ~ 7% increase in oleic acid content in comparison to untreated Tamla plants. The induced mutants could be utilized for the development of high oleic oil rapeseed varieties and for regulatory studies of lipid metabolism in seed oils.

본 연구는 국내에 자생하는 억새 유전자원의 생육특성을 구명하기 위하여 국내외로부터 1,200 여점의 유전자원을 수집하였으며, 그 중에서 재배연수가 3년 이상인 유전자원 960여점을 대상으로 2013년과 2014년 억새의 주요 생육기간 동안인 맹아일로부터 지엽전개일 및 출수일까지의 생육특성을 분석하였다. 그 결과를 요약하면 다음과 같다. 1. 억새의 맹아가 진행되는 4월초부터 생육말기인 11월까지의 2013년도 평균기온은 $19.1^{\circ}C$ 이었고, 2014년의 평균 기온은 $13.9^{\circ}C$ 로 관측되었다. 평균 강수량 및 누적 강수량은 2013년에 3.8 mm와 921.0 mm 이었으며, 2014년에는 4.5 mm와 1092.5 mm 이었다. 2. 2013년 및 2014년 3월초부터 11월말까지의 지표로부터 10 cm 이내의 평균 토양수분 조사결과, 2013년에는 24.9%이었으며 2014년에는 32.2%로 나타났다. 하지만 2013년에는 3월초부터 8월 20일까지 20.7%의 평균 토양수분을 나타낸 반면, 2014년 동일시기의 평균 토양수분은 31.7%로 나타났다. 3. 수집지역별 억새 유전자원의 맹아일로부터 지엽전개일까지 평균 생육일수를 분석한 결과, 경기지역에서 수집한 억새 유전자원의 평균 생육일수가 가장 짧았으나 남부지역으로 내려갈수록 평균 생육일수가 긴 것을 알 수 있었다. 이러한 경향은 2014년도에서도 동일하게 확인되었으며, 지역별로 유의적인 차이를 보였다. 4. 2년간의 조사결과, 전남지역에서 수집한 물억새 중에서 거대 1호(Miscanthus sacchariflorus cv. Geodae 1) 및 우람억새(M. sacchariflorus cv. Uram)는 지엽전개가 가장 늦은 것으로 조사되었으며 맹아일로부터 소요되는 생육일수가 가장 긴 것으로 나타나, 타 억새종에 비하여 영양생장기간이 긴 것으로 판단된다. 5. 2013년도 맹아일로부터 출수일까지의 생육일수와 2014년도 생육일수와의 상관관계 분석결과, 물억새 유전자원의 경우 상관계수(r)가 0.70으로 나타났으며, 참억새 유전자원은 0.89로 나타나 2년간의 생육일수 사이에 높은 상관관계가 있음을 확인하였다. 6. 2014년에 비하여 2013년도 출수가 지연된 요인으로는 높은 기온, 낮은 강수량 및 토양수분의 영향인 것으로 추측할 수 있으며, 3년 이상 동일조건에서 재배한 억새 유전자원의 생육일수는 수집지역간의 유의적인 차이가 있었으며, 억새 유전자원의 출수특성은 현재 재배지역의 환경적 요인보다 자생지에서 다년간 적응되며 나타난 고유한 유전자형의 영향을 받는다는 것을 추측할 수 있다. 【Miscanthus has been considered as the most promising bioenergy crop for lignocellulosic biomass production. In Korea, M. sacchariflorus and M. sinensis can be found easily in all regions. It is a great advantage to utilize as important species with respect to genetic and cross-breeding programs materials for creation of novel hybrids. For successful breeding programs, it is important to precisely understand the variability of flowering traits among Miscanthus species as breeding parents materials. In this study, flowering traits were observed daily in 960 germplasms of two Miscanthus species (M. sacchariflorus and M. sinensis) for growing seasons over 2 years. The flowering process was divided into three stages. ST (sprouting time) was recorded when first leaf of the plant emerged on soil. FS1 (flowering stage 1) and FS2 (flowering stage 2) were recorded when flag leaf was firstly observed, and 1 cm of panicle was showing on at least one stem, respectively. For 2013 and 2014, the latest germplasms exerted flag leaf, i.e. September 30 (DOY of FS1 164.1) and September 4 (DOY of FS1 141.0) occurred M. sacchariflorus cv. Geodae 1 and M. sacchariflorus cv. Uram collected from Southern Korea (Jeollanam-do), while Miscanthus germplasms collected from northern Korea (Gyeonggi-do) which emerged the earliest flag leaf in July and August, significantly decreased DOY. For DOY from ST to FS2, M. sacchriflorus germplasms ranged from 140 to 190 days, and 110 to 170 days for 2013 and 2014. The highest frequency showed to 160 days for 2013, and 150 days for 2014. In M. sinensis germplasms, the highest frequency showed to 180 days for 2013, and 170 days for 2014. In the results of correlation between the day of years from ST to FS2 for 2013 and 2014, M. sacchriflorus and M. sinensis showed high coefficient of correlation (0.70 and 0.89). It can be supposed that flowering characteristics of Miscanthus are largely affected by the unique phenotypic characteristic of native habitat than environmental factors of the current planted site. This study for flowering traits of Miscanthus may provides an important information in order to expedite the introduction as breeding materials for creation of new hybrid.】

This study firstly provides basic data for selection of cultivatable bioenergy grass in barren reclaimed lands applied with solidified sewage sludge. The experimental plots consisted of a plot containing reclaimed land mixed with solidified sewage sludge (MSS 50), a plot covered by solidified sewage sludge (CSS 100), and an original reclaimed soil plot (ORS). The growth, biomass production of bioenergy grasses and soil chemical properties were investigated in each experimental plot for 5 years. The organic matter (OM) and total nitrogen (T-N) content in both MSS 50 and CSS 100 were considerably higher than those in ORS. In bioenergy grasses, M. sacchariflorus cv. Geodae 1 showed an excellent growth and adaptability on reclaimed land applied with solidified sewage sludge. The application of solidified sewage sludge may provided soil nutrition in the reclaimed land due to the fact that bioenergy crops grew better in soils applied with solidified sewage sludge than in untreated soils, and treated soils had higher OM and T-N content than untreated soils. This study suggests that M. sacchariflorus cv. Geodae 1 is the most suitable biomass feedstock crop for biomass production and that solidified sewage sludge may be used as a soil material for cultivation of bioenergy grass on reclaimed lands.

This study was firstly conducted to investigate changes of vegetation and soil characteristics in reclaimed land applied with solidified sewage sludge for the cultivation of bioenergy crops. Each vegetation survey site was approximately on the inside of each experimental plot that consisted of 50% (A-1), 30% (A-2), 15% (A-3), and 5% (A-4) mixture of solidified sewage sludge, and original reclaimed soil (ORS). After the application of solidified sewage sludge, we monitored the changes of vegetation and soil properties for three years. In first year, soil pH, electrical conductivity (EC) and exchangeable content was 9.4~10.8, , and , respectively, while three years later, it decreased to 8.1~8.4, , and , respectively. These results indicated that several of soil chemical elements which have nagative impacts on the plant growth in the plots of mixtures of solidified sewage sludge, steadily declined as the years go by. The vegetations in each survey site were recorded as 6 families and 12 species in 2014, while the vegetations were not occurred at all survey sites in 2012, and only halophytes as Phragmites australis and Suaeda asparagoides were observed in 2013. Diversity of vegetation, which was calculated by shannon index (H'), increased as the season progressed at each experimental plot applied with solidified sewage sludge. In original reclaimed soil, however, there was showed the high community similarity of vegetation due to the fact that P. australis and S. asparagoides were only occurred for survey periods.

One major obstacle of simultaneous saccharification and fermentation (SSF) is that enzymatic hydrolysis in SSF is conducted at non-optimal temperature. To break through this bottleneck, thermotolerant Saccharomyces cerevisiae strains mbc 1-4 were screened by spot-assay from respiration-deficient mutants induced by ethidium bromide. When four strains placed in liquid medium, the strains exhibited significant increased growth and fermentability at 42 °C in comparison to the host. Consequently, S. cerevisiae mbc 2 was selected to be the most suitable for bioethanol production at 42 °C. Miscanthus was pretreated with 1.5 M NaOH at 150 °C for 30 min in 1 L-vessel. As a result, 42.6% of solids containing 77.9% cellulose were recovered. Next, SSF was conducted with pretreated Miscanthus containing 3% glucan to estimate the fermentability of S. cerevisiae mbc 2 at 42 °C. In results, Ethanol concentration and theoretical ethanol yield by S. cerevisiae mbc 2 in 48 h were 15.3 g/L and 90.1%, respectively, whereas those by the control were 8.3 g/L and 49.3%, respectively. In addition, SSF with increased substrate concentration upto 9% glucan resulted in 86.3% and 82.2% of theoretical ethanol yield, respectively. Thus, our approach for SSF with high solid loading using thermotolerant S. cerevisiae mbc 2 contributes to process and microbial strain development for bioethanol production.

Miscanthus sacchariflorus 'Goedae-Uksae 1' (GU) was developed as an energy crop of high productivity in Korea. For the practical use of GU for bioethanol production, a bench-scale continuous pretreatment system was developed. The reactor performed screw extrusion, soaking and thermochemical pretreatment at the following operating conditions: 3 mm particle size, 22% moisture content, 140 °C reaction temperature, 8 min residence time, 15 g/min biomass feeding and 120 mL/min NaOH input. As a result of minimizing NaOH concentration and enzyme dosage, 90.8±0.49% glucose yield was obtained from 0.5 M NaOH-pretreated GU containing 3% glucan with 10 FPU cellulase/g cellulose at 50 °C for 72 h. The separate hydrolysis and fermentation of 0.5 M NaOH-pretreated GU containing 10% glucan with 10-30 FPU for 102 h produced 43.0-49.6 g/L bioethanol (theoretical yield, 75.8-87.6%). Thus, this study demonstrated that continuous pretreatment using a single screw reactor is effective for bioethanol production from Miscanthus biomass.

The possibility of using additive enzymes to improve the saccharification of lignocellulosic substrates with commercial cellulolytic enzymes was studied. Reed (Phragmites communis) and rice (Oryza sativa) straw powders were pretreated with NaOH/steam via a high-temperature explosion system. The saccharification of untreated reed and rice straw powders by commercial enzymes (Celluclast 1.5 L + Novozym 188) was not significantly increased by the addition of xylanases (Xyn10J, XynX), a cellulase (Cel6H), and a β-1,3-1,4-glucanase (BGlc8H) with broad substrate specificity. The saccharification of the pretreated reed and rice straw powders by the commercial enzymes was increased by 10.4 and 4.8 %, respectively, by the addition of BGlc8H. In the presence of Ca2+ and BGlc8H, the saccharification of the pretreated reed and rice straw powders by the commercial enzymes was increased by 18.5 and 11.7 %, respectively. No such effect of Ca2+ was observed with Xyn10J, XynX, or Cel6H. The results suggest that the enzymatic conversion of lignocellulosic biomass to reducing sugars could be enhanced by certain additive enzymes such as β-1,3-1,4-glucanase, and that the enhancement could further be increased by Ca2+.

The rice stem borer (Chilo suppressalis Walker) was one of the most destructive pest of rice for the 1960s and 1970s in Korea. Recently, it is newly recognized as a potential risk factor to the biomass yield of bioenergy crops. The current research was firstly conducted to investigate overwintering larvae population density and pattern of rice stem borer attacking Miscanthus sacchariflorus cv. Geodae 1 which is referred to as an ideal lignocellulosic bioenergy crop in Korea. Population density of larvae per 1 m 2 in stems and rhizomes at the Miscanthus experimental plots and rates of damage (wormhole, abscission) of M. sacchariflorus cv. Goedae 1 were investigated from October 2012 to March 2013. The population of larvae per 1 m 2 in stems of Miscanthus were 23, 4, 1, and 1 in October, November, December 2012, and January 2013, respectively. Over the same period, the population of larvae in basal stem rots and rhizomes were increased, whereas decreased in stems. Interestingly, the positions of larvae for overwintering in Miscanthus were confirmed to 5~10 cm below the soil surface such as basal stem rot and rhizome, whereas the most common overwintering position known in rice is a part of stem on the ground such as rice straw and rice stubble. It would suggest that the larvae gradually moved to bottom of stems and rhizomes in soil in line with decline in temperature. Moreover, the damage rates of stems per 1 m 2 were up to more than 50% in some places. In conclusion, this might be the first report that rice stem borer could affect the productivity of biomass of Miscanthus in case of mass cultivation. Moreover, it should be necessary to make a decision in insect control management for this bioenergy feedstock and other related crops.

The use of rapeseed (Brassica napus L.) or leaf mustard (Brassica juncea L. Czern) meal or both as organic fertilizer not only improves the soil environment and crop productivity by supplying nutrients but also has nematicidal effects. This study aimed to establish the optimal application levels of rapeseed and leaf mustard meal for stronger nematode control in tomato. Tomato is one of the most important solanaceous crops which is severely damaged by nematodes. At first, meal (120 g of varying mixing ratios of rapeseed and leaf mustard meal) was mixed with sterilized soil (1 kg). The optimal ratio of rapeseed:leaf mustard meal for effective nematode control was 20:100 g/kg of soil. Progoitrin and gluconapin were the most abundant glucosinolates found in rapeseed meal, while sinigrin was the most abundant in leaf mustard meal. The amount of sinigrin increased if the leaf mustard meal proportion increased in the meal mixture. Although the content of sinigrin in optimal ratio mixture of rapeseed and leaf mustard meal is lower than only leaf mustard meal, it is presumed that nematocidal effects of the mixture are better than that of the single component due to the high contents of progoitrin and gluconapin. So, we propose that rapeseed and leaf mustard meal mixture at an appropriate ratio can be used as an environmentally friendly nematocide.

This study investigated the production of bioethanol from Miscanthus using a specially designed twin-screw extruder (designated CHEMET) with sodium hydroxide. Pretreatment parameters were optimized using a response surface methodology and we evaluated the efficiency of pretreatment through the biomass to ethanol ratio (BTER). Optimum pretreatment conditions were 95 °C, 0.4 M sodium hydroxide concentration, 80 rpm twin-screw speed, and flow rate of 120 mL/min. Under these optimum conditions, actual BTER was 66 ± 2%, compared with a theoretical maximum of 67 ± 3%. Simultaneous saccharification and fermentation (SSF) was used to optimize enzyme and biomass dosage, giving a maximized ethanol concentration of 67.0 g/L and an ethanol conversion rate of 88.1% for 25% loading of pretreated Miscanthus with 30 FPU/g glucose of enzyme. The findings contribute to the development of continuous-production methods of obtaining bioethanol from lignocellulosic biomass.

Because of its high biomass productivity and nutrient-use efficiency, Miscanthus spp. have emerged as promising bioenergy crops. Polyploidism in Miscanthus species is important because it allows non-native countries to cultivate sterile types, such as triploid M. × giganteus, in order to prevent ecosystem disturbance. Although M. sacchariflorus and M. sinensis are considered to be native to Korea, China, and Japan, accurate information describing the ploidy levels of these species has not yet been well established. To evaluate rough ploidy levels, 215 accessions of Miscanthus species were estimated by relative fluorescence intensities of DAPI-stained nuclei. After evaluation of rough ploidy levels, 20 plants were randomly selected by species and ploidy levels, and ploidy levels were examined by counting chromosomes, estimating propidium iodide-stained DNA content with flow cytometry, and measuring sizes of stomata and caryopsis. Among the 20 plants examined, 3 were diploid and 6 were tetraploid M. sacchariflorus (4.56 ± 0.01 and 8.90 ± 0.14 pg/2C nuclear DNA content, respectively), while 6 were diploid and 3 were triploid M. sinensis (5.40 ± 0.18 and 8.29 ± 0.33 pg/2C nuclear DNA content, respectively). One plant was a putative triploid M. × giganteus having 7.31 pg/2C nuclear DNA content, which was similar to an M. × giganteus plant from Illinois, USA having 7.23 pg/2C nuclear DNA content. We confirmed the occurrence of diploid and tetraploid M. sacchariflorus and M. sinensis plants as well as a putative triploid M. × giganteus native to Korea. Thus, measurement of the size of stomata and caryopsis allowed prediction of ploidy levels in the field and laboratory.

Miscanthus is referred to as an ideal lignocellulosic bioenergy crop, which can be used to generate heat, power, and fuel, as well as to reduce carbon dioxide emissions. The new Miscanthus sacchariflorus genotype named Geodae-Uksae 1 was recently collected from damp land in southern Korea. This study investigated the growth characteristics of Miscanthus genotypes, and developed a specific, sensitive, and reproducible sequence characterized amplified region (SCAR) marker to distinguish new M. sacchariflorus genotype Geodae-Uksae 1 from other native Miscanthus species in Korea. Growth characteristics such as stem length, stem diameter, and dry weight of Geodae-Uksae 1 were greater than those of normal M. sacchariflorus. The genotypes within Geodae-Uksae 1 were had the highest genetic similarity. A putative 1,800-bp polymorphic sequence specific to Geodae-Uksae 1 was identified with the random amplified polymorphic DNA (RAPD) N8018 primer. The sequence-characterized amplified region (SCAR) primers Geodae 1-F and Geodae 1-R were designed based on the unique RAPD amplicon. The SCAR primers produced a specific 1,799-bp amplicon in authentic Geodae-Uksae 1, whereas no amplification was observed in other Miscanthus species. The SCAR marker could contribute to identify Geodae-Uksae 1 among native Miscanthus species. The new Miscanthus genotype Geodae-Uksae 1 has great potential as an alternative lignocellulosic biomass feedstock for bioenergy productions.

The world demand of renewable bioenergy as an alternative transportation fuel is greatly increasing. Research for bioethanol production is currently being progressed intensively throughout the world. Therefore it will be necessary to develop bioethanol production with cellulosic materials. In this study, the yield of ethanol production was evaluated by simultaneous saccharification and fermentation (SSF) using sodium hydroxide pretreated sorghum sudangrass hybrids. Composition analysis of 11 varieties of sorghum sudangrass hybrids was performed for selection of excellent variety to efficiently produce bioethanol. The content of cellulose, hemicellulose, lignin and ash of these varieties were 32~39%, 19~24%, 17~22% and 6~11%, respectively. Among these varieties, 4 varieties of sorghum sudangrass hybrids were selected for the evaluation of ethanol yield and those were pretreated with 1 M NaOH solution at for 30 min using high temperature explosion system. After pretreatment, samples were neutralized with tap water. It contained 52~57% of cellulose. Simultaneous saccharification and fermentation (SSF) was carried out for 48 h at by Saccharomyces cerevisiae CHY1011 using Green star variety. The yield of ethanol was 92.4% and the amount of ethanol production was estimated at 6206 L/ha.

To determine the possibility of solidified sewage sludge for use as a soil cover material in reclaimed land, the growth of energy crops and soil chemical properties investigated in each experimental plots during 2 years (2010and 2011). The experimental plots consisted of the mixing with solidified sewage sludge plot (SS50), the covering with solidified sewage sludge plot (SS100), and the original re-claimed land plot (ORL) on reclaimed land for the intended landfill in Sudokwon Landfill Site Management Corporation (SLC). Plant height, measured in the second year (2011), was highest in the Geodae 1 grown at plots treated with solidified sewage sludge. The growth of energy crops cul-tivated in both SS50 and SS100 were better than in ORL. The contents of organic matter (OM) and total nitrogen (T-N) at both SS50 and SS100 were considerably higher than that of the ORL over 2 years. However, the soil from ORL showed higher salinity with high contents of exchange-able Na + cation than that of SS50 and SS100 over 2 years. We consider that soil chemical and physical properties on reclaimed land used in this study could be improved by the application of solidified sewage sludge due to following reasons. Firstly, the application of solidified sewage sludge may provide soil nutrients on reclaimed land i.e. the growth of energy crops better than in ORL, resulted in more OM and T-N contents in SS50 and SS100. Secondly, the top layers mixed or covered with solidified sewage sludge on reclaimed land may be prevented the salinity accumulation due to capillary rise to surface soil, and improved the cultivation layer for effectively propagating the rhizomes of energy crops. Thus the solidified sewage sludge may be a great soil cover materials for cultivation of bioenergy crops in reclaimed land.

Optimization of initial total sugar concentration of sweet sorghum juice, aeration time and aeration rate on ethanol production was performed by response surface methodology (RSM). The optimum conditions for ethanol production from concentrated sweet sorghum juice were determined as follows: initial total sugar concentration, 21.2 Brix; aeration time, 7.66h; aeration rate, 1.22 vvm. At the optimum conditions, the maximum ethanol yield was predicted to be 91.65% by model prediction. Similarly, 92.98% of ethanol yield was obtained by verification experiment using optimum conditions after 48 h of fermentation. This result was in agreement with the model prediction.

This study was conducted to improve weeding effect by rice bran farming technique. In the weeding effect experiment by application timing control of rice bran and soybean cake, weeding efficacy was the highest at the treatment of conventional application of rice bran. The treatment of soybean cake with rice bran was unfavorable, but Echinochloa crus-galli occurred little at the treatment of soybean cake at 5 days after transplanting, so it is thought that further study about inhibitor of early E. crus-galli occurrence in soybean cake is necessary. Cultivating weeder was effective at the treatments of rice bran and soybean cake together, of which weed occurrence was more than conventional rice bran, and precise experiments about cultivating weeding time and method will be necessary.Key words: cultivating weeder; rice bran; soybean cake; weeding effect. 서 언 최근 친환경농업에 대한 관심이 높아짐에 따라 농업 환경에 대한 부하를 최소화하려는 노력이 점점 증가하고 있다. 우리나라는 2013년까지 2003년 대비 화학비료와 농약 사용량을 40% 줄인다는 계획 하에 종합병해충 관리시스템 도입과 화학비료 줄이기 및 친환경농업 확대 등 다양한 시책을 시행하고 있다(농촌진흥청 2004). 그 중에서 주목받고 있는 방법 중 하나가 쌀겨농법이다. 이것은 일본에서 유기농 쌀 생산 농가들에 의해서 시작된 농법으로, 유기농의 가장 큰 문제인 잡초제거를 이 농법으로 일정부분 해결할 수도 있다는 점에서 도입하는 농가가 증가하고 있다(농업과학기술원 2005).

In this study, alkaline pretreatment at a bench scale (15-L capacity) was performed to obtain a higher solid residue for the SSF (simultaneous saccharification and fermentation) of Miscanthus sacchariflorus “Goedae-Uksae 1” (GU) under the following conditions: 1 M NaOH concentration, 150 °C, and 60 min residence time. Compositional analysis and scanning electron microscope analysis revealed the pretreatment to be highly effective for achieving delignification and morphological changes. Spiral impellers were used for the rapid liquefaction of pretreated GU into slurry, and no additional nutrients were added to the fermentation mixture to reduce overall process costs. The SSF was subsequently conducted in a laboratory-scale fermenter (5-L capacity) for 108 to 120 h with 12% and 16% glucan containing pretreated GU. Consequently, 62.8 g/L and 81.1 g/L of ethanol were obtained. Based on these data, the theoretical ethanol yields from 1 kg of GU (dry weight base) were estimated at 164.6 to 171.1 g/L.

A CO2-added ammonia explosion pretreatment was performed for bioethanol production from rice straw. The pretreatment conditions, such as ammonia concentration, CO2 loading level, residence time, and temperature were optimized using response surface methodology. The response for optimization was defined as the glucose conversion rate. The optimized pretreatment conditions resulting in maximal glucose yield (93.6 %) were determined as 14.3 % of ammonia concentration, 2.2 MPa of CO2 loading level, 165.1 °C of temperature, and 69.8 min of residence time. Scanning electron microscopy analysis showed that pretreatment of rice straw strongly increased the surface area and pore size, thus increasing enzymatic accessibility for enzymatic saccharification. Finally, an ethanol yield of 97 % was achieved via simultaneous saccharification and fermentation. Thus, the present study suggests that CO2-added ammonia pretreatment is an appropriate process for bioethanol production from rice straw. Electronic supplementary material The online version of this article (doi:10.1007/s00449-014-1165-x) contains supplementary material, which is available to authorized users.

The sequence-characterized amplified region (SCAR) marker for simultaneous identification of Miscanthus sacchariflorus, Miscanthus sinensis, and Miscanthus x giganteus was developed. In this study, it was attempted for the first time to develop the SCAR marker for detecting the molecular phenotypes among Miscanthus species. Randomly amplified polymorphic DNA technique was applied for this study and one fragment which is unique to M. sacchariflorus was identified and then sequenced. Based on the specific fragment, one SCAR primer pair designated as MS62-5F and MS62-5R was designed to amplify an approximately 1,000 bp DNA fragment within the sequenced region. Diagnostic PCR was performed using the primer pair. Using this SCAR marker, approximately 1,000 bp and 1,200 bp DNA fragments were obtained in M. sacchariflorus and M. sinensis, respectively. Moreover, M. x giganteus was obtained both bands at the same time. The result showed that this SCAR marker can clearly distinguish the M. sacchariflorus, M. sinensis, and M. x giganteus, respectively.