Kim J.-Y.,Seoul National University |
Oh S.,Seoul National University |
Hwang H.,Seoul National University |
Moon Y.-H.,Bioenergy Crop Research Center |
Choi J.W.,Seoul National University
Energy | Year: 2014
Liquid bio-oils were produced from miscanthus (Miscanthus sacchariflorus) by fast pyrolysis at various temperature ranges (350-500 °C) with a short residence time and their physicochemical properties were determined to evaluate the potentials for biofuel utilization. Before operating fast pyrolysis, miscanthus was subjected to ICP-ES (inductively coupled plasma emission spectrometer) analysis and TGA (thermogravimetric analysis). It was learned that miscanthus was thermally unstable due to large amounts of inorganic constituents including potassium (5643.8 ppm), calcium (711.0 ppm) and magnesium (1403.1 ppm). With fast pyrolysis, the yield of bio-oil gradually decreased with increasing temperature and residence time. The maximum yield of bio-oil was ca. 58.9 wt% at 350 °C with a residence time of 1.9 s. The HHV (higher heating value) of bio-oil was determined up to 18.0 MJ/kg produced at 400 °C with a residence time of 1.9 s. The water content of bio-oil was ranged from 21.1 to 56.9 wt%. GC/MS (gas chromatography/mass spectrometry) analysis showed that bio-oil was mostly composed of carbohydrate derivatives and lignin derivatives. 1-(Acetyloxy)-2-butanone, furfural, dihydro-methy-furanone and levoglucosan were the predominant low molecular weight compounds that originated from carbohydrate and those from lignin were guaiacol 4-vinylphenol and syringol. © 2014 Elsevier Ltd. All rights reserved.
Kang K.E.,Changhae Ethanol Co. |
Han M.,Changhae Ethanol Co. |
Moon S.-K.,Changhae Ethanol Co. |
Kang H.-W.,Changhae Ethanol Co. |
And 3 more authors.
Fuel | Year: 2013
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. © 2013 Elsevier Ltd. All rights reserved.
Kim D.U.,Sunchon National University |
Kim H.J.,Sunchon National University |
Jeong Y.S.,Sunchon National University |
Na H.B.,Sunchon National University |
And 6 more authors.
Journal of the Korean Society for Applied Biological Chemistry | Year: 2015
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+. © 2015, The Korean Society for Applied Biological Chemistry.
Lee H.M.,Pusan National University |
Park Y.H.,Pusan National University |
Jun T.-H.,Pusan National University |
Kwon S.W.,Pusan National University |
And 8 more authors.
Plant OMICS | Year: 2015
Sweet potato (Ipomoea batatas L. Lam) is one of the most commercially important crops worldwide and still the major food source in many developing countries. In order to accelerate the marker-assisted selection for sweet potato breeding, development and optimal use of easy-to-use and sequence-specific genetic markers, are required. Here, we analyzed 200 pairs of the random amplified polymorphic DNA (RAPD) markers to uncover the polymorphisms in sweet potato and subsequently developed 13 pairs of sequence-characterized amplified region (SCAR) markers. In contrast to the random amplification of RAPD markers, the newly-developed SCAR markers revealed lower ratio of polymorphisms, but showed higher repeatability, user-friendly and were sequence-specific. Furthermore, we employed these markers to exploit the genetic diversity of 27 Korean sweet potato cultivars, which could be distinguished and grouped. Overall, these results show that the newly-developed and sequence-specific SCAR markers could be used for marker-assisted selection (MAS) for breeding for elite sweet potato varieties in South Korea.
Lee S.J.,Pusan National University |
Kim J.Y.,Pusan National University |
Kim Y.C.,Pusan National University |
Ha T.J.,South Korean National Institute of Animal Science |
And 5 more authors.
Journal of Horticultural Science and Biotechnology | Year: 2013
This study was conducted to develop biomarkers to identify 26 cultivars of Korean sweet potato (Ipomoea batatas L. Lam) using omics-based methods. Random amplification of polymorphic DNA (RAPD) markers revealed that 75 random 10-mer primers generated 50 polymorphic RAPD markers from the 28 Korean sweet potato cultivars. Six sweet potato cultivars were selected for further analysis by proteomic and metabolomic approaches based on their flesh colour (two each having cream, orange, or purple flesh) and by a dendrogram generated using the polymorphic RAPD bands. Changes in the proteomes of these six sweet potato cultivars were investigated by two-dimensional gel electrophoresis (2-DGE) coupled with matrix-assisted, laser desorption/ionisation tandem time-of-flight mass spectrometry (MALDI-TOF/TOF MS) analysis. Overall, ten protein spots were expressed differentially between the six cultivars and identified by MALDI-TOF/TOF MS. Among these, an ATP-dependent zinc metalloprotease and the chaperone protein, ClpC1, accumulated specifically in the cultivars 'Singeonmi' and 'Jami', respectively. Furthermore, metabolomic analysis, using reversed-phase high performance liquid chromatography (HPLC) coupled with liquid chromatography-electrospray ionisation mass spectrometry (LC-ESI-MS), revealed that four polyphenolic compounds accumulated differentially in the six sweet potato cultivars. Members of the caffeoylquinic acid family were detected at the highest levels in 'Juhwangmi'. These results suggest that the proteins and metabolites that accumulate differentially may be used as biomarkers to identify Korean sweet potato cultivars.