• Asian-Australasian Journal of Animal Sciences
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• v.23 no.5
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• pp.680-692
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• 2010

This paper gives an overview of the availability, nutritive quality, and possible strategies to improve the utilization of rice straw as a feed ingredient for ruminants. Approximately 80% of the rice in the world is grown by small-scale farmers in developing countries, including South East Asia. The large amount of rice straw as a by-product of the rice production is mainly used as a source of feed for ruminant livestock. Rice straw is rich in polysaccharides and has a high lignin and silica content, limiting voluntary intake and reducing degradability by ruminal microorganisms. Several methods to improve the utilization of rice straw by ruminants have been investigated in the past. However, some physical treatments are not practical because of the requirement for machinery or treatments are not economical feasible for the farmers. Chemical treatments, such as NaOH, $NH_3$ or urea, currently seem to be more practical for onfarm use. Alternative treatments to improve the nutritive value of rice straw are the use of ligninolytic fungi (white-rot fungi), with their extracellular ligninolytic enzymes, or specific enzymes degrading cellulose and/or hemicellulose. The use of fungi or enzyme treatments is expected to be a more practical and environmental-friendly approach for enhancing the nutritive value of rice straw and can be costeffective in the future. Using fungi and enzymes might be combined with the more classical chemical or physical treatments. However, available data on using fungi and enzymes for improving the quality of rice straw are relatively scarce.

• Journal of the Korean Wood Science and Technology
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• v.24 no.4
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• pp.74-81
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• 1996

리그닌분해능(分解能)이 높은 균주(菌株)로 선발(選拔)된 Coriolus versicolor-13 (CV-13), LKY-7 및 LKY-12세 균주(菌株)에 대하여 균체외(菌體外) laccase 생산(生産)을 검토(檢討)하였다. Glucose-peptone broth에서 균체외(菌體外) laccase활성(活性)은 CV-13의 경우 3일 이상배양후(以上培養後)에 나타났고 LKY-7과 LKY-12균주(菌株)의 laccase 활성(活性)은 배양(培養) 2일째에 검출(檢出)되었다. 탄소원(炭素源)으로서는 maltose가 glucose와 비슷한 laccase 생산효과(生産效果)를 나타냈고 질소원(窒素源)으로서는 유기태질소(有機態窒素)가 무기태(無機態) 질소(窒素)보다 효과적(效果的)이었다. Laccase 유도물질(誘導物質)로서는 2,5-Xylidine이 가장 우수하였으며 1mM 이하(以下)의 농도(濃度)에서는 유도효과(誘導效果)가 크게 나타났으나 1.5mM 이상(以上)의 농도(濃度)에서는 laccase생산(生産)이 억제(抑制)되었고, 균사생장(菌絲生長) 초기(初期)에 첨가(添加)하는 것이 효과적(效果的)으로 나타났다. SDS-PAGE 후, CV-13 균주(菌株)의 균체외(菌體外) 단백질(蛋白質)에서는 약 69, 66, 25, 23, 19kDa 크기의 laccase band가 5개 나타났고 LKY-7 균주(菌株)에서는 27kDa과 19kDa 크기의 2개 band가, LKY-12 균주(菌株)에서는 22, 20, 17kDa 크기의 laccase band가 3개 나타났다.

• Journal of Microbiology and Biotechnology
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• v.16 no.2
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• pp.226-231
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• 2006

Several white-rot fungi are able to produce extracellular lignin-degrading enzymes such as manganese peroxidase (MnP), lignin peroxidase (LiP), and laccase. In order to enhance the production of laccase and MnP using Trametes versicolor KCTC 16781 in suspension culture, the effects of major medium ingredients, such as carbon and nitrogen sources, on the production of the enzymes were investigated. The decolorization mechanism in terms of biodegradation and biosorption was also investigated. Among the carbon sources used, glucose showed the highest potential for the production of laccase and MnP. Ammonium tartrate was a good nitrogen source for the enzyme production. No significant difference in the laccase production was observed, when glucose concentration was varied between 5 g/l and 30 g/l. As the concentration of nitrogen source increased, a lower MnP activity was observed. The optimal C/N ratio was 25 for the production of laccase and MnP. When the concentrations of glucose and ammonium tartrate were simultaneously increased, the laccase and MnP activities increased dramatically. The maximum laccase and MnP activities were 33.7 U/ml at 72 h and 475 U/ml at 96 h, respectively, in the optimal condition. In this condition, over 90% decolorization efficiency was observed.

• Korean Journal of Microbiology
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• v.44 no.1
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• pp.10-13
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• 2008

Endocrine disrupting chemicals (EDCs) are hard to be degraded in nature, and are also accumulated in diverse organisms. They finally give negative effects to human through the food web. White rot fungi which have lignin-degrading enzymes have high potentials for degradation of recalcitrant compounds, and a white rot fungus, Phlebia tremellosa, isolated in Korea show good degrading activity against the endocrine disrupting phthalates. We have isolated a laccase cDNA which was involved in the degradation of EDCs, and constructed a laccase expression vector to use in the genetic transformation of P. tremellosa. The expression vector was stably integrated into the chromosomal DNAs and showed increased laccase activity in transformants. One of transformants showed not only increased degradation of several EDCs but also faster estrogenic decreasing activities generated by the EDCs.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.2
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• pp.83-90
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• 1997

An unbleached hardwood kraft pulp was bleached in vitro with partially purified manganese peroxidase (MnP) from the fungus Phanerochaete sordida YK-624 without the addition of MnSO$_4$ in the presence of oxalate, malonate or gluconate known as manganese chelator, When the pulp was treated without the addition of MnSO$_4$, the pulp brightness increased by about 10 points in the presence of 2 mM oxalate, but the brightness did not significantly increase in the presence of 50 mM malonate. Residual MnP activity decreased faster during the bleaching with MnP without MnSO$_4$ in the presence of malonate than in the presence of oxalate. Oxalate reduced MnO$_2$ which already existed in the pulp or was produced from $Mn^{2+}$ by oxidation with MnP and thus supplied $Mn^{2+}$ to the MnP system. Thus, bleaching of hardwood kraft pulp with MnP, using manganese originally existing in the pulp, became possible in the presence of oxalate, a good manganese chelator and reducing reagent. Properties of partially purified MnPs from liquid cultures of white rot fungi, Ganoderma sp. YK-505, Phanerochaete sordida YK-624 and Phanerochaete chrysosporium were compared. MnP from Ganoderma sp. YK-505 was superior to MnPs from P. sordida YK-624 and P. chrysosporium in stabilities against high temperature and high concentration of $H_2O$$_2$. The MnP from Ganoderma sp. YK-505 differed in pH-activity profile from other MnPs. These data suggest that MnP from Ganoderma sp. YK-505 has different structure from those of other fungi. Bleaching of hardwood kraft pulp using the MnP from ganoderma sp. YK-505 is now in progress.

• Journal of the Korean Wood Science and Technology
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• v.34 no.4
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• pp.46-53
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• 2006

This study was to screen white-rot fungi possesing strong lignin degrading enzymes, glucose-1 oxidase (GOD), laccase (LAC) and Mn-peroxidase (MnP), based on their decolorization activity of Remazol Brilliant Blue R (RBBR). In the midst of 20 tested fungi, 9 isolates were shown 4 kinds of activities such as RBBR decolorization, GOD, LAC and MnP. Relatively high active strains were identified as Phlebia radiata, Trametes versicolor, Abortiporus biennis, Gleophyllum odoratum and Cerrena unicolor. In particular, T. versicolor, G. odoratum, and C. unicolor, which have high activities of LAC, were used to confirm the optimal temperature and pH and to evaluate the effect of inducer, 2,5-xylidine on their LAC activity. The optimum temperatures for mycelial growth were $28^{\circ}C$ for T. versicolor and G. odoratum, and $25^{\circ}C$ for C. unicolor. The optimum pH for mycelial growth was 5.5. Three strains showed the increase of LAC enzyme activity by the addition of 2,5-xylidine. T. versicolor had the highest LAC activity of $22,700nkat/{\ell}$, corresponding to 11.3 times, G. odoratum $15,400nkat/{\ell}$, 9 times and C. unicolor $17,330nkat/{\ell}$, 5.5 times higher than those of the control.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.4
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• pp.18-27
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• 1998

Biopulping is defined as the treatment of wood chips with lignin-degrading fungi prior to pulping. Fungal pretreatment prior to mechanical pulping reduces electrical energy requirements during refining or increases mill throughput, improves paper strength, reduces the pitch content, and reduces the environmental impact of pulping. Our recent work involved scaling up the biopulping process towards the industrial level, investigating both the engineering and economic feasibility. We envision the process to be done in either a chip-pile or silo-based system for which several factors need to be considered: the degree of decontamination, a hospitable environment for the fungus, and the overall process economics. Currently, treatment of the chips with low-pressure steam is sufficient for decontamination and a simple, forced ventilation system maintains the proper temperature, humidity, and moisture conditions, thus promoting uniform growth of the fungus. The pilot-scale trial resulted in the successful treatment of 4 tons of wood chips (dry weight basis) with results comparable to those on a laboratory. Larger, 40-ton trials were also successful, with energy savings and paper properties comparable with the laboratory scale. The overall economics of the process also look very favorable and can result in significant annual savings to the mill. Although the current research has focused on biopulping for mechanical pulping, it is also beneficial for sulfite chemical pulping and some applications to recycled fiber have been investigated.

• Journal of Mushroom
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• v.10 no.2
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• pp.74-82
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• 2012

Sixty strains of Pleurotus ostreatus, white-rot fungi, were screened for production ability of their lignocellulolytic enzymes to selectively wood degradation. That results were shown that all of screened strains were produced lignocellulolytic enzymes on 2nd screening liquid culture medium. However, cellulase activity of selected six strains of P. ostreatus was low in avicel-yeast-peptone liquid culture medium. In the case of xylan degrading enzyme, No. 6 and No. 38 strains produced a xylanase(above 1.0U/ml) and a 1,4-${\beta}$-xylosidase (above 0.15 U/ml). Examination of the ligninolytic enzyme profiles of selected thirteen strains of the P. ostreatus, in the presence of Remazol Brilliant Blue R(RBBR), were observed that laccase(Lac) activity were earlier reached maximum level(0.8-2.0 U/ml) and then Mn-dependent peroxidase (MnP) were reached maximum level(0.5-1.5 U/ml) in glucose-yeast-peptone(GYP) medium. On the other hand, activity of lignin peroxidase(LiP) was not detected in this medium. I selected the No. 42 strain of P. ostreatus produced high levels of Mn-dependent peroxidase and laccase based on the screening method.

• Journal of Korea Foresty Energy
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• v.23 no.2
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• pp.21-28
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• 2004

Three different strains of Lentinula edodes, Sanlim 5-Ho, Sanlim 6-Ho and Nongki 3-Ho, were cultured in the sawdust media of Mongolian oak(Quercu mongolica Fisch) for 90 days under dark and light conditions(each 30 days) and fruiting period(30 days). Weight loss of sawdust media was determined after fungal cultures and the contents of ergosterol in fungal mycelia were quantified by HPLC analysis followed by solvent extraction. Compared with the two other fungal strains$(8\%)$, weight loss of Sanlim 5-Ho was slightly lowered to $7\%$. The level of ergosterol content, a parameter for fungal growth, was continuously enhanced in Sanlim 5-Ho for dark and light incubation periods. However, Sanlim 6-Ho and Nongki 3-Ho recorded the maximized fungal growth under light condition. In fruiting periods the ergosterol contents were lowered in the three strains. Intra- and extracellular enzymes during cultural and fruiting periods were also characterized. The activity of Mn-peroxidase and laccase, which are characteristics enzymes for white rot fungi as lignin degrading enzymes, were determined as a high level overall the periods. As cellulose degrading indicators, the activity of CMCase, avicelase, xylanase and glucanase were detectable in initial incubation period.

• Journal of Korea Foresty Energy
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• v.24 no.2
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• pp.1-9
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• 2005

After manufacturing fermentation system for degrading pig manure using environmentally friendly technique, performance of the system and characteristics of wood chips and pig manure fermented in the system were analyzed. Results from this study shows that proper fermentation temperature($55{\sim}60^{\circ}C$) reached 3days after the system started and degradation rate, which expresses fermentation performance of system, was $180{\iota}$/day. Even as progressing the fermentation of wood chips and pig manure mixture, the amount of extractives drawn out by alkali, and alcohol-benzene and lignin content was not varied. However, ash content in wood was increased. The inorganic compounds in pig manure seem to be transferred into wood chip. On the other hand holocellulose contents in wood were decreased a little. Holocellulose seems to be consumed as the second carbon source in fermentation process. Results through analysis of inorganic- and heavy metal elements contents in wood chips and pig manure fermented in long term process shows that inorganic elements($Ca^{2+},\;Mg^{2+},\;K^+,\;Na^+$ etc.) contents were increased with fermentation time and heavy metal elements(Cd, As, Cu etc.) which cause environmental pollution were not detected. Number of microorganisms including bacteria, actinomycetes, and fungi, the number of C.F.U(Colony Forming Unit) was increased while temperature in fermentation system was abruptly increased.