發(fā)布時(shí)間：2018-09-01 16:43

【摘要】：甘蔗渣是甘蔗制糖的三大副產(chǎn)物之一,目前主要用于燃燒和造紙,利用率較低。甘蔗渣具有價(jià)格便宜、數(shù)量龐大、成分穩(wěn)定和來源集中等特點(diǎn),用于生產(chǎn)反芻動(dòng)物粗飼料具有極大的前景。然而,由于甘蔗渣中木質(zhì)素含量過高,且木質(zhì)素可與纖維素和半纖維素會(huì)形成致密木質(zhì)纖維結(jié)構(gòu),導(dǎo)致微生物和酶利用率低,不宜直接應(yīng)用于生產(chǎn)高品質(zhì)粗飼料。故本研究以甘蔗渣為原料,利用氫氧化鈉/尿素預(yù)處理,降低木質(zhì)素含量和提高其可發(fā)酵性。隨后,通過青貯方式對(duì)預(yù)處理后甘蔗渣進(jìn)行發(fā)酵,并探索添加劑及調(diào)制條件對(duì)青貯品質(zhì)的影響。通過對(duì)比單一氫氧化鈉和氫氧化鈉/尿素兩種方法對(duì)甘蔗渣的預(yù)處理效果,實(shí)驗(yàn)結(jié)果表明兩種方法均對(duì)降解木質(zhì)素和提高酶解率有顯著作用。其中氫氧化鈉/尿素混合預(yù)處理木質(zhì)素降解率為61.83%,纖維素酶解率為72.68%。通過響應(yīng)面試驗(yàn)優(yōu)化得到氫氧化鈉/尿素降解甘蔗渣的最佳條件為:尿素濃度為10.50%、氫氧化鈉濃度為4.44%、預(yù)處理時(shí)間為6.3 h、處理溫度為60℃。以此條件進(jìn)行預(yù)處理后的甘蔗渣木質(zhì)素降低了 62.45%,纖維素提升了 65.27%,酶解后還原糖量為0.518 g/g(相對(duì)于甘蔗渣)。向預(yù)處理后的甘蔗渣中添加乳酸菌及纖維素酶,以提高青貯品質(zhì),結(jié)果表明:添加乳酸菌或纖維素酶均有利于提高青貯效果。二者混合添加的試驗(yàn)組青貯后pH降低至4.27,乳酸含量、可溶性糖含量和干物質(zhì)粗蛋白含量分別提高了 56.52%、61.15%和42.22%,氨態(tài)氮/粗蛋白(NH3/TN)、中性洗滌纖維(NDF)和酸性洗滌纖維(ADF)分別下降了 26.89%、12.08%和 5.04%。通過正交試驗(yàn)對(duì)不同調(diào)制條件下甘蔗渣青貯飼料品質(zhì)和營(yíng)養(yǎng)成分指標(biāo)進(jìn)行了分析,得出因素影響作用大小依次為:甘蔗渣水分含量粉碎粒徑糖蜜添加量,并由此得到的最佳調(diào)制條件為:甘蔗渣含水量60%-65%、粉碎粒徑為2.36 mm、糖蜜添加量為9%。在此條件下得到的青貯飼料pH值為4.22,乳酸/總酸為66.41%,NH3/TN為4.81%,干物質(zhì)中粗蛋白含量為3.60%,NDF 和 ADF 分別為 68.21%和 56.07%。
[Abstract]:Bagasse is one of the three by-products of sugarcane sugar making, which is mainly used in burning and papermaking. Bagasse has the characteristics of low price, large quantity, stable composition and concentrated source, so it has great prospect in producing ruminant forage. However, because the lignin content in bagasse is too high and lignin can form dense wood fiber structure with cellulose and hemicellulose, the utilization ratio of microorganism and enzyme is low, so it is not suitable to be directly used in the production of high quality crude feed. Therefore, using bagasse as raw material, sodium hydroxide / urea pretreatment was used to reduce lignin content and improve its fermentability. After that, bagasse was fermented by silage, and the effects of additives and modulation conditions on the quality of the silage were explored. The pretreatment effects of single sodium hydroxide and sodium hydroxide / urea on bagasse were compared. The results showed that both methods had significant effects on lignin degradation and enzymatic hydrolysis. The lignin degradation rate was 61.83% and the cellulolysis rate was 72.68% after mixed pretreatment with sodium hydroxide / urea. The optimum conditions for the degradation of bagasse with sodium hydroxide / urea were obtained by response surface test: urea concentration was 10.50, sodium hydroxide concentration was 4.44, pretreatment time was 6.3 h, treatment temperature was 60 鈩，

本文編號(hào)：2217773