發(fā)布時(shí)間：2018-03-10 20:54

  本文選題：微生物脂肪酶　切入點(diǎn)：解脂耶氏酵母　出處：《上海應(yīng)用技術(shù)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：微生物脂肪酶具有較高的水解、酯化和轉(zhuǎn)酯活力,在脂合成、生物柴油制備和對(duì)映體拆分等領(lǐng)域應(yīng)用十分廣泛。因其穩(wěn)定性差等不良因素,微生物脂肪酶在飼料工業(yè)中的應(yīng)用范圍較窄。本實(shí)驗(yàn)室成功構(gòu)建一種新型解脂耶氏酵母脂肪酶,然后在適宜保護(hù)劑的作用下,獲得了具有較高穩(wěn)定性的脂肪酶制劑。本文研究了四種不同來(lái)源微生物脂肪酶的酶學(xué)性質(zhì)對(duì)比,同時(shí)在動(dòng)物試驗(yàn)中,研究了解脂耶氏酵母脂肪酶在肉雞飼養(yǎng)過(guò)程中的添加效果,對(duì)肉雞生長(zhǎng)性能、脂質(zhì)代謝及其安全性進(jìn)行了全面評(píng)估。主要研究工作和結(jié)果摘要如下:1.對(duì)解脂耶氏酵母脂肪酶(YLL)與皺褶假絲酵母脂肪酶(CRL)、梳棉狀嗜熱絲胞菌脂肪酶(TLL)和米根霉脂肪酶(ROL)進(jìn)行對(duì)比,得到4種不同來(lái)源的脂肪酶在最適溫度、pH,熱穩(wěn)定性及pH穩(wěn)定性的差異。進(jìn)而對(duì)YLL的底物特異性及動(dòng)力學(xué)參數(shù)進(jìn)行了探究。YLL的最適溫度為40℃,在30℃和40℃孵育2小時(shí)后,YLL具有最佳的穩(wěn)定性,殘余酶活分別為85%和80%左右;在pH 2-9范圍內(nèi)比較了四種不同脂肪酶的穩(wěn)定性,YLL在低pH下展現(xiàn)了最佳的穩(wěn)定性,在pH 5的條件下孵育2小時(shí)后,殘余酶活均在50%以上。YLL的最適底物為對(duì)硝基苯酚棕櫚酸酯(C16),對(duì)長(zhǎng)鏈單甘酯(C14、C16、C18)有較好的水解效果。2.考察了 YLL體外水解大豆油的最佳條件,測(cè)定不同時(shí)間梯度下的水解率。水解大豆油的最佳反應(yīng)條件為:反應(yīng)時(shí)間6h、溫度40℃、加酶量600 U、水油比3: 1。添加保護(hù)劑噴霧干燥獲得兩種YLL劑型,并在體外模擬動(dòng)物內(nèi)消化環(huán)境,對(duì)產(chǎn)生的酶解產(chǎn)物進(jìn)行定性定量分析。兩種劑型展現(xiàn)了較好的穩(wěn)定性,在孵育2 h后分別具有55%和48%的殘余酶活,其中,劑型A(YLL+20%脫脂奶粉)具有最佳的穩(wěn)定性。并以肉雞大豆油飼料為底物,添加相同酶活力單位的YLL上清液和YLL劑型,反應(yīng)6 h后,利用氣相色譜儀檢測(cè)飼料油脂中關(guān)鍵脂肪酸的含量,發(fā)現(xiàn)YLL劑型相比于游離酶展現(xiàn)了較高的水解率,其中,對(duì)于脂肪酸C18: 2,劑型A達(dá)到65%的水解率,劑型B達(dá)到58%的水解率。3.開(kāi)展了解脂耶氏酵母脂肪酶在白羽肉雞中的飼養(yǎng)效果研究�？疾炝嗽诎子鹑怆u的日糧中添加解脂耶氏酵母脂肪酶,對(duì)生長(zhǎng)性能和血液生化指標(biāo)的影響,并對(duì)腸道微生物菌群的變化進(jìn)行了研究。結(jié)果顯示添加脂肪酶顯著降低了料重比(FCR, P0.05),提高了血清中甘油三酯的含量(P0.05)。4.還開(kāi)展了脂肪酶及單細(xì)胞蛋白添加劑對(duì)肉雞飼用安全性的全面評(píng)估。結(jié)果顯示單獨(dú)添加酵母菌和脂肪酶以及混合添加酵母菌和脂肪酶的5組與對(duì)照組相比,屠宰率、全凈膛率、胸肌率、腿肌率、腹脂率、內(nèi)臟指數(shù)、空腸長(zhǎng)度指數(shù)均無(wú)顯著差異,展現(xiàn)了良好的飼用安全性。
[Abstract]:Microbial lipase has high hydrolysis, esterification and transesterification activity. It is widely used in lipid synthesis, biodiesel preparation and enantiomeric resolution. Microbial lipase was used in feed industry in a narrow range. A novel lipase was successfully constructed in this laboratory, and then it was used as a protective agent. A stable lipase preparation was obtained. The enzymatic properties of four different microbial lipases were studied. In animal experiments, the effects of lipase addition by yeasts in broiler breeding were studied. To the growth performance of broilers, A comprehensive evaluation of lipid metabolism and its safety was carried out. The main research work and results were summarized as follows: 1. Lipase of YLL) and CRLL, TLL) and Rhizopus oryzae Lipase of Candida crassifolia, TLL) and Rhizopus oryzae. For comparison, The difference of pH, thermal stability and pH stability of lipases from four different sources was obtained. The substrate specificity and kinetic parameters of YLL were investigated. The optimum temperature of lipase was 40 鈩，

本文編號(hào)：1595039