LI ZHIXIA

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application/pdf博士学位論文の要旨及び審査結果の要旨 (Summary of Thesis(DR))2084800 bytesothe

LI, ZHIXIA

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Application of Superheated Steam forUtilization of Japanese Cedar Resources著者 LI ZHIXIA号 5学位授与番号 83URL http://hdl.handle.net/10097/37992LI ZHIXIA氏　　　　　　　名　李　志　霞授　与t　学　位　博士(学術)学　位　記　番　号　学術(環)博第83号学位授与年月　日　平成20年3月25日学位授与の根拠法規　学位規則第4条第1項研究科,専攻の名称　東北大学大学院環境科学研究科(博士課程)環境科学専攻　　ノ学位論文題　目　Application of Superheated Steam for Utilization of員員委教査導審文持論Japanese Cedar Resources(過熱水蒸気処理によるスギ資源の有効利用に関する研究)東北大学教授　井奥　洪二主査　東北大学教授　井奥　洪二　東北大学教授　石田　秀輝東北大学教授　井上　千弘　東北大学教授　笠井　憲雪(医学系研究科)東北大学准教授　吉成　浩一(薬学研究科)論文　内　容要　旨Cedaristhe largest tree species in Japan, accounts for 18% (4520 kha) artificial forestinthe country･Althoughcedar forest has contributed to maintaining the relevant ecological (including biological diversity),economic,and social氏mction,the large-scale cedar forest has brought some worries based on environment forJapanese, for example,the nationwide cedarPollen allergen and forest devastation and soil erosion caused by a lotof landslidesincedarforests whenthey meet heavy rainstorm. A lot of thined woodand discard wood have notbeen in use. To relievethe environmentalrisks and to enl1anCe economic profit of cedar forests, other effectiveutilizations of cedar resources besides as the resources for energy or woodindustry are desired. The volatileorganic chemicals (essential oil) inthe cedarhave been reported to have various bioactivities such asantifungal,antimite,antitermiticand antimosquito, onthe other hand,these chemicalsinduce P4501dependent microsomalenzyme in laboratoryanimals, andthus limitthe application of cedar woodchips as beddings for laboratoryanimals.Asshownin Figure 1, superheated steam(SHS) is a high-en血alpy, low-density watervapor phase, and provides advantagesincluding Increased heat transfer, an oxygen-kee circumstance, accelerated drying rate andimproved energy efficiency. Therefore, SHSunder血e mild conditions (below 200 oC) isinferred to be effective medium for enhancingthe extraction of organic substances　frombiomass. By now, only a few works have been2育A≡ar〃P ?5 ?Olid 優｢ﾒ?_ tC.P SVC uquld 鳴??B??;SHS -97-Sew-　Supercriticat Waterub-CW･ Subc州ical WaterSHSI Superheated SteamSVPC- Saturated VaporProssuro Gun/○100  200    374     HP- High PressureTempe,atu,. (｡C)　3忘. "諾cTa7;opienr.atureFigure 1 Water phase diagramdone fbr血e use of SHS- as an extraction medium. In this thesis, SHS has been developed as a novel extractiontechnique to utilize cedar resources. One is to extractthe useful organic substancesfromfresh cedar leaves, andanother is to Lconvert cedar woodchips into a safe bedding material for laboratory animals by removlngthosevolatile harmful organic compounds from woodchips. Therefore,this thesis consists of the followlng PartS･In chapter I, the research backgrounds were described. The aim and research method applied in this studywere presented･　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　ノIn chapter II, the extraction properties or SHS were invest1gated comprehensively. Firstly, a novelcontinuous extraction apparatus was developed. Then, extraction properties of SHS were investigated bydeterminingthe oil yield kom cedar leaves under various temperature-pressure conditions. Extraction mechanismwas investigated in detail based onthe analysis of the heat transfer properties of SHSand the effects of watercontent in materials.Asa result, SHS isolated a higher oil yield than th早t Obtained by conventional steamdistillation. Increaslng temperature and pressure were found to improve the oil yield effectively. Analysis ofextraction mechanism has revealed two points: i) because of its high heat transfer efficiency, SHS cantransferthemore energy to a low-temperature material by condensation of water atthe surface of materials; ii) because of thelarge heat capacity, water content contained in materials would absorb heat &om extraction medium,and transfermore energy tothose organic moleculesaround it leading to assistance of the extraction of those organicsubstances. Driving force derived斤om evaporation of intrinsic waterand diffusion of oil itself promote theextraction orthe essential oil in SHS.In chapter III, because sesquiterpenes were thought to be the dominant compounds responsible for variousbioactivities of essential oil of cedar, in也is chapter, we developed血e utilization or SHS on仇e selectiveextraction of sesquiterpenes &om cedarleaves. In addition, to explore the utilization of the extracts obtained bySHS,theirantimicrobial activities were examined by disk-diffusion method. The properties of SHS on selectiveextraction of organic substances were compared withthose with hexane and methanol.Asa result,the followlngShave been demonstrated: increaslng temperature and pressure of steamare favorable to improvethe yields ofsesquiterpenes･ A temperature more than 150　0Cenhanced the extraction of diterpenes signincantly. Theextractions of some larger molecular-weight compounds(diterpenesand alkanes)and polar organic compounds(ester and carboxylic acid) have been accelerated byincreaslng Steam Pressure. For selective extraction ofsesquiterpenes, a condition of 120-150　0C intemperature　and 0.2-0.3　MPa in pressure wasdemonstrated to be effective. Compared to hexaneextraction and methanol extraction, SHS exhibitedselectivity　on extraction of sesquiterpenes　andsesquiterpene alcohols. Compared to organic solventextracts, SHS extracts showed high antimicrobialFigure 2 Determination of grow血Iinhibiting har°of two m croorganisms by cedar extracts (SHSOl~2:SHS extracts obtained at 170 oC and 120 oC; HEO:h xane extracts; MEO: methanol extracts.ー98-activity･ SHS is proved to be a promising method for selective extraction of some special active compoundsagainstthe grow仇offungi, bacteria and mycetes.In chapter IV･ We developed the application of SHS as an extraction technique to convert cedar shaving intoa kind of safe bedding for laboratory animals･ In details, the optimumtreatment condition was investigated, fornot only effective removal of those harmful compounds for laboratory animals (volatile sesquiterpenes andaromatic hydrocarbons) &om cedar bedding, also protecting and improving the properties of woody structure. And血en, a large-scale practical apparatus was developed･ As a result, the optimal conditions f♭r the improvement orcedarbedding were 140 oC, 0135 MPa and for 60min･ Under this condition,the total essential oil in cedar beddingcanbe effectively extracted by over 50%,andthose volatile compounds such as sesquiterpene and naphathalene-derived aromatics can be almost removed･ AIso･under this condition SHS treatment increased the adsorption9aPaCity of the cedar bedding for ammonia gas･ Therefore,the improved cedar bedding is expected to improve thehousing･ environment by lowenng the ammonia concentration･ These results indicated that the improvement ofcedar bedding provides the possibility orthe use of cedar beddings as laborat叩animal bedding.In chapter V, because cytochrome P450s enzymes (P450) play an important roleindetoxification ofxenochemicals includingtherapeutic drugs, countless toxins and carcinogens, in this chapter, we examined theeffects of single oral administration of essential oil of Japanese cedar bedding (EOJC), as well as the effects of theimproved cedar beddingsfrom which partial EOJC had been removed, on the P450 enzyme systems inmice. Inaddition, the effects of the improved cedar bedding on the growth and reproductive properties of animals wereexamined血ough a long-te- (17 weeks) housing experiment and a 6-week housing experiment of mice. EOJCwas collected during SHS processlng Ofcedar bedding and was administeredorally to mice･ Between血ys 1 and 2 a洗eradministration, hepatic P450s weresigniflCantly induced as showninFigure3･ Histopathological examination showedthe oral administration of essential oilcaused lesion to hepatocytes and gastricmucosa of mice･ The houslng Studyor mice indicated that丘esh cedarbeddings increased　血e levels ofthese P450s in mouse liver, whereasmice housed in the improved cedarbedding showed significantly lowerlevels of P450S, indicating that SHS00　00　00　008642(%)Ie^aru!at0Jd0*　　　　　　　*　　　　　　　　**■』lr -Cn51 2　4　8　　　CO51 2　4　8　　　Cu51 2　4　8　　　CQ51 2　4　8CYP3As CYPI As cYp2E 1 CYP2CsFigure　3　Hepatic P450　protein levels in mice a洗er oraladministration of EOJC. Male mice were treated with EOJC(2000mgn'g)and killed at 0.5, I, 2, 4,and 8 days. The value forcontrol mice (C) was set at lO0%. Data represent the mean土S.D.(n - 5). ～ P < 0.05, vs. control mice.effectively removed those harmful organic compounds (volatile sesquiterpenes and naphthalene-derived aromatics)for animals from bedding･ The housing study showed that SHS processing of-99-bedding did not bring slgnificant effects on the body weight, blood, the litter size at birth andweaning in mice, indicating no or minimal effTect on the growth and reproductive capacity of mice･The improved cedar bedding was showed to be a kind of safTe bedding for animal experiments togaln reliable data.In chapter VI, a summary based･ on results and discussions from the previouschapters isノprovided･ Superheated steam has been demonstrated to be an effective teclmiquefor the isolation ofessential oil &om plants. Superheated steam processlng Promoted the utilization of cedar resourcesand recycling cedar wastes, suggesting that supe血eated steam is a promlSlng method on improvlngand recycling biomass wastes.-100-論文審査結果の要旨水は､従来から反応媒体として研究されてきたが､過熱水蒸気についての既往の研究は多くなく､その性質ならびに応用できる範囲は未だによく分かっていない｡過熱水蒸気とは､臨界点より低い温度､飽和蒸気圧未満の低圧力領域の水蒸気を指す｡この温度圧力領域の水蒸気は､密度が低く､誘電率､イオン積も常温の水より低いという特徴を有し､有機反古を促進する反応場を与えると考えられている.本論文は､スギの葉､端材や廃材を資源化することを研究目的としたものである｡過熱水蒸気を利用ヒてスギ資源から有価物質の抽出を行い､さらにスギ廃材を改質して実験動物用の床敷材としての有効利用を試みており､全6章で構成されている｡第-章"htmduction"では､スギ資源の活用が期待されている社会背景および反応媒体としての過熱水蒸気の特性を述べた｡第二章"Properhes ofsuperheated steamasanextraction medium''では､過熱水蒸気による流通型抽出装置を開発し､スギの葉を対象として､過熱水蒸気の抽出特性を調べた｡一反応条件として温度一水蒸気分圧を制御し次の結果を得た｡すなわち､窒素あるいは飽和水蒸気による抽出と比較し､過熱水蒸気では対流伝熱および凝縮伝熱によって有機物質の抽出が促進されることを明らかにした｡第三章"Apphcadon of superheated steamto selective extraction of orgmic compunds血)m cedarleavesand utili2ntion of extracts"では､過熱水蒸気によるスギの葉からの有機物の選択的抽出を行った｡過熱水蒸気は､有機溶媒と比較してセスキテルペンおよびセスキテルペンアルコール類の抽出に有効であることを示した｡セスキテルペン類は各種の生物活性に関与していると考えられており､注目すべき物質である｡微生物学的見地から､スギの菓からの抽出物の生物活性成分の定性分析を行い､さらに､過熱水蒸気抽出物の優れた抗菌性を発見した｡第四章"lmpmvement ofcedarbedding by usingthe superheated steamprtxess"では､スギの実験動物床敷としての応用を提案し､過熱水蒸気処理の大型実用機によってスギ材の改質を行った｡床敷に必要と考えられる木質構造を破壊することなく､実験動物の代謝に影響する揮雛のセスキテ/レペン類や芳香族炭化水素を選択的に抽出し除去することを試みた｡その結果､過熱水蒸気処理によりスギ材からセスキテ/レヾン､ナフタリン誘導体を効率的に除去し､床敷材に応用可能な程度にまで品質を向上させることができた｡第五章``Effbcts of the improved cedar bedding on laboratory animals''では､過熱水蒸気処理によって改質して得られたスギ床敷材について､実際の実験動物に対する使用の可能性を実験動物-与える影響を調べることによって検討した｡具体的には､マウスの成長､繁殖､臓器組織構造､血液性状､肝臓酵素誘導特性などに及ぼす影響を調べた｡その結果､改質したスギ床敷はマウスの成長を妨げず､安全な床敷材として飼育に利用することが可能であることが確認された｡第六章"Sumary"では､第二章から第五章までの内容を要約し､本論文を次のように総括した｡すなわち､ 200℃以下の過熱水蒸気を用いた反応は､環境に対する負荷が低く､低コスト･低エネルギーといった利点があるとし､過熱水蒸気は環境保全の理念に合致した技術であると述べている｡次に､日本全国で過多とされるスギ材の活用を目指し､小動物用の床敷材-の応用が可能であることを示している｡また､過熱水蒸気によるバイオマス未利用資源の有効活用についても言及している｡以上のように､本論文は､過熱水蒸気を用いてバイオマスの有効利用を検討し､応用展開の一例を示したものである｡その研究内容は､工学･医学･薬学という多方面から学際的にアプローチしたものであり､今後の環境科学の発展に寄与するところが大きい｡よって､本論文は博士(学術)の学位論文として合格と認める｡-101-

Application of Superheated Steam for Utilization of Japanese Cedar Resources

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過熱水蒸気処理によるスギ資源の有効利用に関する研究

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