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1、廣西農(nóng)業(yè)科學(xué)2010,41(7):637-641GuangxiA咖culturalSciences·637·降解生淀粉真菌的篩選、鑒定及其產(chǎn)生淀粉酶的性質(zhì)研究林海娟1’2,冼亮1.2,段承杰1一,劉君梁-一,馮家勛·,2.(1廣西大學(xué)生命科學(xué)與技術(shù)學(xué)院,南寧530005;2廣西亞熱帶生物資源保護(hù)利用重點(diǎn)實(shí)驗(yàn)室,南寧530005)摘要:以生木薯粉為唯一碳源,對(duì)收集的土壤樣品懸浮液進(jìn)行培養(yǎng)、12/l(I溶液染色,經(jīng)搖瓶復(fù)篩和菌株發(fā)酵上清液BSDE活力測(cè)定,篩選出10株RSDE活力較高的真菌;)td'RSDE活力最高的真菌菌株I一31進(jìn)行形態(tài)學(xué)觀察和ITS(Internaltrans
2、cribedspacer)序列分析,將其鑒定為青霉屬。對(duì)青霉l一3l的酶學(xué)性質(zhì)進(jìn)行測(cè)定,結(jié)果發(fā)現(xiàn)其RSDE對(duì)生木薯淀粉的最適作用pH和溫度分別為5.0和55。C;分別以玉米和大米為底物時(shí),其RSDE的生淀粉分解活力比(RDA)較高,為59.O%和58.8%;青霉l一31RSDE對(duì)生木薯粉的吸附率約為37.O%。HPLC檢測(cè)發(fā)現(xiàn),以該菌株RSDE水解生木薯粉4h,僅釋放出葡萄糖,說明青霉1—31產(chǎn)生的RSDE主要為生淀粉糖化酶。電鏡觀察結(jié)果發(fā)現(xiàn),經(jīng)青霉1—31RSDE處理,可使生木薯粉顆粒光滑完整的表面變得粗糙,形成無數(shù)小坑,說明青霉1—31RSDE對(duì)生淀粉具有較強(qiáng)的水解作用。因
3、此,青霉l一31RSDE在各種生淀粉如木薯、玉米、大米和馬鈴薯生淀粉等加工業(yè)中具有一定的應(yīng)用潛力。關(guān)鍵詞:生淀粉酶;青霉;篩選;降解;酶性質(zhì)中圖分類號(hào):Q949.31文獻(xiàn)標(biāo)識(shí)碼:A文章編號(hào):1002—8161(2010)07—0637—05Screeningandidentificationofrawstarchhydrolyzingfungalstrainsandcharacteristicsoftheirrawstarch-degradingenzymeLINHai-juanl一,XIANLian91一,DUANCheng-jiel一,LIUJun-lian91一,F(xiàn)ENG
4、Jia-xunl,2‘(1CollegeofLifeScienceandTechnology,GuangxiUniversity,Nanning530005,China;2GuangxiKeyLal)0ratoryofSubtropicalBioresourceConservationandUtilization,Nanning530005,China)Abstract:Thesuspensionsofcollectedsoilsampleswereculturedinisolatedplatesbyusingrawstarchassolecarbonsource,andsta
5、inedbyICKIsolutionafterculturingfor5days.Thestrainwithsignificanthydrolyzingzonewasisolatedandpurified.Tenfungalstrainswitllhigherrawstarch-degradingenzyme(RSDE)activitytorawcassavastarchwerescreenedandRSDEactivityWagdeterminedinfermentedsupernatant.Among10strains,afungalstrain1—31showinghig
6、herRSDEactivityWasidentifiedonthebasisofmorphologicalobservationandinternaltranscribedspacer(ITS)regionsequenceanalysis,asaPcnicilliumsp.TheRSDEofPenicillium1-31showedmaximumactivityatpH5.0and50℃.Thevaluesofrawstarch-degrsdingability(RDA)oftheRSDEwemabout59.0and58.8%whenC01andricewereusedast
7、hesubstrate,respectively.TheadsorptionrateofRSDEinPenicil]ium1-31toraWcassavastarchWasabout37.O%.HPLCanalysisrevealedthattheBSDEcouldreleasegluco艙onlyfromrawcassavastarchin4hours.indicatingthattheRSDEfromPenicillium叩.1-31Wasmainlyrawstarch-degradin