木质纤维素的酶水解

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1、木质纤维素的酶水解Biologicalconversionofcellulosicbiomasstofuelsandchemicalsoffersthehighyieldstoproductsvitaltoeconomicsuccessandthepotentialforverylowcosts.Enzymatichydrolysisthatconvertslignocellulosicbiomasstofermentablesugarsmaybethemostcomplexstepinthisprocessduetosubstrate-related

2、andenzyme-relatedeffectsandtheirinteractions.Althoughenzymatichydrolysisoffersthepotentialforhigheryields,higherselectivity,lowerenergycostsandmilderoperatingconditionsthanchemicalprocesses,themechanismofenzymatichydrolysisandtherelationshipbetweenthesubstratestructureandfunctio

3、nofvariousglycosylhydrolasecomponentsisnotwellunderstood.Consequently,limitedsuccesshasbeenrealizedinmaximizingsugaryieldsatverylowcost.Thisreviewhighlightsliteratureontheimpactofkeysubstrateandenzymefeaturesthatinfluenceperformance,tobetterunderstandfundamentalstrategiestoadvan

4、ceenzymatichydrolysisofcellulosicbiomassforbiologicalconversiontofuelsandchemicals.Topicsaresummarizedfromapracticalpointofviewincludingcharacteristicsofcellulose(e.g.,crystallinity,degreeofpolymerizationandaccessiblesurfacearea)andsolubleandinsolublebiomasscomponents(e.g.,oligo

5、mericxylanandlignin)releasedinpretreatment,andtheireffectsontheeffectivenessofenzymatichydrolysis.Wefurtherdiscussthediversity,stabilityandactivityofindividualenzymesandtheirsynergisticeffectsindeconstructingcomplexlignocellulosicbiomass.Advancedtechnologiestodiscoverandcharacte

6、rizenovelenzymesandtoimproveenzymecharacteristicsbymutagenesis,post-translationalmodificationandover-expressionofselectedenzymesandmodificationsinlignocellulosicbiomassarealsodiscussed.基于酶水解技术基础上的纤维素乙醇生产技术是20世纪80年代生物质技术的主要研究领域，自从20世纪70年代“能源危机”之后，美国能源部一直积极支持规模以上乙醇生产，并建立独立部门用于管理和支

7、持这项工作。21虽然通过纤维素酶水解纤维素生物质产生的生物燃料和化学产品提供了更高的收益率，较高的选择性，降低能源成本以及相对化学过程更温和的操作条件等，但是这种技术在那个时代依然被判定为高风险行业[1]。然而新兴生物技术为纤维素乙醇生产成本降低并使其更具有竞争性提供了重要的保证。改进的稀酸预处理方法和二战时期发现的纤维素酶生产菌Trichodermareesei是20世纪80年代纤维素乙醇历史性成本降低的主要原因[2-4]。RutgersUniversity通过经典突变技术和菌种选育获得了来源于野生型T.reeseiQM9414的著名纤维素生产菌株T

8、richodermareeseiRut30[5]。杰能科公司的纤维素酶150L非常高效是因为β