甘蔗渣制备青贮饲料的研究
发布时间：2018-09-01 16:43
【摘要】：甘蔗渣是甘蔗制糖的三大副产物之一,目前主要用于燃烧和造纸,利用率较低。甘蔗渣具有价格便宜、数量庞大、成分稳定和来源集中等特点,用于生产反刍动物粗饲料具有极大的前景。然而,由于甘蔗渣中木质素含量过高,且木质素可与纤维素和半纤维素会形成致密木质纤维结构,导致微生物和酶利用率低,不宜直接应用于生产高品质粗饲料。故本研究以甘蔗渣为原料,利用氢氧化钠/尿素预处理,降低木质素含量和提高其可发酵性。随后,通过青贮方式对预处理后甘蔗渣进行发酵,并探索添加剂及调制条件对青贮品质的影响。通过对比单一氢氧化钠和氢氧化钠/尿素两种方法对甘蔗渣的预处理效果,实验结果表明两种方法均对降解木质素和提高酶解率有显著作用。其中氢氧化钠/尿素混合预处理木质素降解率为61.83%,纤维素酶解率为72.68%。通过响应面试验优化得到氢氧化钠/尿素降解甘蔗渣的最佳条件为:尿素浓度为10.50%、氢氧化钠浓度为4.44%、预处理时间为6.3 h、处理温度为60℃。以此条件进行预处理后的甘蔗渣木质素降低了 62.45%,纤维素提升了 65.27%,酶解后还原糖量为0.518 g/g(相对于甘蔗渣)。向预处理后的甘蔗渣中添加乳酸菌及纤维素酶,以提高青贮品质,结果表明:添加乳酸菌或纤维素酶均有利于提高青贮效果。二者混合添加的试验组青贮后pH降低至4.27,乳酸含量、可溶性糖含量和干物质粗蛋白含量分别提高了 56.52%、61.15%和42.22%,氨态氮/粗蛋白(NH3/TN)、中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)分别下降了 26.89%、12.08%和 5.04%。通过正交试验对不同调制条件下甘蔗渣青贮饲料品质和营养成分指标进行了分析,得出因素影响作用大小依次为:甘蔗渣水分含量粉碎粒径糖蜜添加量,并由此得到的最佳调制条件为:甘蔗渣含水量60%-65%、粉碎粒径为2.36 mm、糖蜜添加量为9%。在此条件下得到的青贮饲料pH值为4.22,乳酸/总酸为66.41%,NH3/TN为4.81%,干物质中粗蛋白含量为3.60%,NDF 和 ADF 分别为 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，
本文编号：2217773
[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，
本文编号：2217773
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