Phygen Research Institute

Daejeon, South Korea

Phygen Research Institute

Daejeon, South Korea
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Patel S.K.S.,Konkuk University | Mardina P.,Konkuk University | Kim D.,Phygen Research Institute | Kim S.-Y.,Shin Ansan University | And 3 more authors.
Bioresource Technology | Year: 2016

Raw biogas can be an alternative feedstock to pure methane (CH4) for methanol production. In this investigation, we evaluated the methanol production potential of Methylosinus sporium from raw biogas originated from an anaerobic digester. Furthermore, the roles of different gases in methanol production were investigated using synthetic gas mixtures of CH4, carbon dioxide (CO2), and hydrogen (H2). Maximum methanol production was 5.13, 4.35, 6.28, 7.16, 0.38, and 0.36 mM from raw biogas, CH4:CO2, CH4:H2, CH4:CO2:H2, CO2, and CO2:H2, respectively. Supplementation of H2 into raw biogas increased methanol production up to 3.5-fold. Additionally, covalent immobilization of M. sporium on chitosan resulted in higher methanol production from raw biogas. This study provides a suitable approach to improve methanol production using low cost raw biogas as a feed containing high concentrations of H2S (0.13%). To our knowledge, this is the first report on methanol production from raw biogas, using immobilized cells of methanotrophs. © 2016 Elsevier Ltd.

Jeya M.,Konkuk University | Kalyani D.,Konkuk University | Dhiman S.S.,Konkuk University | Kim H.,Korea University | And 4 more authors.
Bioresource Technology | Year: 2012

Enzymatic saccharification of woody biomasses was performed using glycoside hydrolases from Stereum hirsutum, a newly isolated fungal strain found to secrete efficient glycoside hydrolases. The strain showed the highest β-glucosidase, cellobiohydrolase, endoglucanase, endoxylanase, laccase, and filter paper activity of 10.3, 1.7, 10.3, 29.9, 0.12, and 0.58. U/ml, respectively. Among the various biomasses tested for saccharification, pine biomass produced maximum reducing sugar. Response surface methodology was used to optimize the hydrolysis of pine biomass to achieve the highest level of sugars. The parameters including enzyme, substrate concentration, temperature and pH were found to be critical for the conversion of pine biomass into sugars. Maximum saccharification of 49.7% (435. mg/g-substrate) was obtained after 96. h of hydrolysis. A close agreement between the experimental results and the model predictions was achieved. S. hirsutum could be a good choice for the production of reducing sugars from cellulosic biomasses. © 2012 Elsevier Ltd.

Singh R.K.,Konkuk University | Tiwari M.K.,Konkuk University | Kim D.,Phygen Research Institute | Kang Y.C.,Konkuk University | And 2 more authors.
Applied Microbiology and Biotechnology | Year: 2013

An endo-1,4-β-xylanase gene, xylcg, was cloned from Chaetomium globosum and successfully expressed in Escherichia coli. The complete gene of 675 bp was amplified, cloned into the pET 28(a) vector, and expressed. The optimal conditions for the highest activity of the purified recombinant XylCg were observed at a temperature of 40 C and pH of 5.5. Using oat-spelt xylan, the determined K m, V max, and k cat/K m values were 0.243 mg ml-1, 4,530 U mg-1 protein, and 7,640 ml s-1 mg-1, respectively. A homology model and sequence analysis of XylCg, along with the biochemical properties, confirmed that XylCg belongs to the GH11 family. Rice straw pretreated with XylCg showed 30 % higher conversion yield than the rice straw pretreated with a commercial xylanase. Although xylanases have been characterized from fungal and bacterial sources, C. globosum XylCg is distinguished from other xylanases by its high catalytic efficiency and its effectiveness in the pretreatment of lignocellulosic biomass. © 2012 Springer-Verlag Berlin Heidelberg.

Ramachandran P.,Konkuk University | Kim T.-S.,Konkuk University | Dhiman S.S.,Konkuk University | Li J.,Konkuk University | And 5 more authors.
Bioprocess and Biosystems Engineering | Year: 2015

Lignocellulases from Armillariagemina and Pholiotaadiposa are efficient in hydrolyzing aspen and poplar biomass, respectively. In the present study, lignocellulosic enzymes obtained from a fungal consortium comprising P. adiposa and A. gemina were used for the saccharification of sunflower stalks. Sunflower stalks were thermochemically pretreated using 2 % NaOH at 50 °C for 24 h. The saccharification process parameters including substrate concentration, enzyme loading, pH, and temperature were optimized using response surface methodology to improve the saccharification yield. The highest enzymatic hydrolysis (84.3 %) was obtained using the following conditions: enzyme loading 10 FPU/g-substrate, substrate 5.5 %, temperature 50 °C, and pH 4.5. The hydrolysis yield obtained using the enzymes from the fungal consortium was equivalent to that obtained using a mixture of commercial enzymes Celluclast and Novozyme β-glucosidase. Addition of up to 500 ppm of heavy metal ions (As, Cu, Fe, Mn, Ni, Pb, and Zn) during saccharification did not significantly affect the saccharification yield. Thus, the biomass grown for phytoremediation of heavy metals can be used for the production of reducing sugars followed by ethanol fermentation. © 2015 Springer-Verlag Berlin Heidelberg

Dhiman S.S.,Konkuk University | Selvaraj C.,Konkuk University | Li J.,Konkuk University | Singh R.,Konkuk University | And 6 more authors.
Fuel | Year: 2016

This study evaluates the phytoremediation potential of canola biomass, which was grown on soils contaminated by several metals. The increase in metal concentration was measured in different parts of the growing biomass. Nearly 95 mg zinc/kg soil of the zinc supplied to the soil accumulated within the roots of canola. To test the suitability of the canola biomass for bioethanol production, a saccharification was performed after phytoextraction of metals. Armillaria gemina and Pholiota adiposa were co-cultured to obtain a highly active lignocellulase cocktail. Saccharification yields (SY) of 71.8% and 74.4% were obtained with biomass contaminated with nickel and copper, respectively. Under similar conditions, Celluclast® 1.5 L in combination with commercial β-glucosidase resulted in a SY of 73.4%. Fermentation using the hydrolysate of canola biomass used in the phytoremediation yielded 68.9% of bioethanol. To our knowledge, this is the first study where canola biomass used for phytoremediation was tested for bioethanol production through saccharification. © 2016 Elsevier Ltd.

Jagtap S.S.,Konkuk University | Woo S.M.,Phygen Research Institute | Kim T.-S.,Konkuk University | Dhiman S.S.,Konkuk University | And 2 more authors.
Fuel | Year: 2014

In this study, we aimed to identify plant species capable of remediating diesel-contaminated soil and to convert their biomass to bioethanol. Three plant species (Pinus densiflora, Populus tomentiglandulosa, and Thuja orientalis) were grown on an area of soil contaminated with 6000 mg/kg of diesel to assess the effects of addition of a microbial consortium and fertilizer on remediation efficacy. Diesel-contaminated soil resulted in reduced plant biomass for most of the tested plants. However, in diesel-contaminated P. densiflora pots containing the microbial consortium, shoot biomass was greater than that in pots treated with diesel alone. Additionally, fertilizer application was found to be the most important factor for efficient diesel degradation. Plant biomass in diesel-contaminated soil was pretreated and used as a substrate for hydrolysis using lignocellulases from Armillaria gemina, a newly isolated fungal strain. The strain showed the highest β-glucosidase (15 U/mL), cellobiohydrolase (34 U/mL), endoglucanase (146 U/mL), endoxylanase (1270 U/mL), laccase (0.16 U/mL), mannanase (57 U/mL), lignin peroxidase (0.31 U/mL) and filter paper (1.72 U/mL) activities. The highest saccharification yield was obtained with P. densiflora (52%). The A. gemina enzymes hydrolyzed the woody biomass used for phytoremediation and resulted in a high level of reducing sugar (375 mg/g-substrate). © 2013 Elsevier Ltd. All rights reserved.

Ramachandran P.,Konkuk University | Zhao Z.,Konkuk University | Singh R.,Konkuk University | Dhiman S.S.,Konkuk University | And 4 more authors.
Bioprocess and Biosystems Engineering | Year: 2014

A highly efficient β-1,4-mannanase-secreting strain, Pholiota adiposa SKU0714, was isolated and identified on the basis of its morphological features and sequence analysis of internal transcribed spacer rDNA. P. adiposa β-1,4-mannanase was purified to homogeneity from P. adiposa culture supernatants by one-step chromatography on a Sephacryl gel filtration column. P. adiposa β-1,4-mannanase showed the highest activity toward locust bean gum (V max = 1,990 U/mg protein, K m = 0.12 mg/mL) ever reported. Its internal amino acid sequence showed homology with hydrolases from the glycoside hydrolase family 5 (GH5), indicating that the enzyme is a member of the GH5 family. The saccharification of commercial mannanase and P. adiposa β-1,4-mannanase-pretreated rice straw by Celluclast 1.5L (Novozymes) was compared. In comparison with the commercial Novo Mannaway® (113 mg/g-substrate), P. adiposa β-1,4-mannanase-pretreated rice straw released more reducing sugars (141 mg/g-substrate). These properties make P. adiposa β-1,4-mannanase a good candidate as a new commercial β-1,4-mannanase to improve biomass pretreatment. © 2014 Springer-Verlag.

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