膨化玉米秸秆发酵饲料对肉羊育肥效果的影响

为研究膨化玉米秸秆发酵饲料对肉羊育肥的效果,选取杂交绵羊(南非美利奴羊×东北细毛羊)16只,随机分为2组,每组8只,每只为一个重复。对照组以干玉米秸秆为粗饲料来源,试验组以膨化玉米秸秆发酵饲料为粗饲料来源,两组精料相同,每天每只1 000 g。日粮均以先精后粗的方式饲喂。试验共计90 d。试验结束后每组随机选择3只羊进行屠宰。结果表明:(1)试验组干物质采食量比对照组提高20%(P<0.05),净增重比对照组提高14.16%(P>0.05);(2)试验组羊血液中总蛋白含量显著高于对照组(P<0.05),而尿素氮含量显著低于对照组(P<0.05),其他血液指标两组间未见显著性差异(P>0.05);(3)试验组瘤胃食靡中的滤纸酶活性和果胶酶活性均显著高于对照组(P<0.05),木聚糖酶活性两组间未见显著性差异(P>0.05)。     

玉米秸秆与废弃白菜混贮料的发酵特性及其乳酸菌分离鉴定

将玉米秸秆(Zea mays)与废弃白菜(Brassica pekinensis)进行不同比例(玉米秸秆与废弃白菜鲜质量比分别为29∶19、27∶21、25∶23、23∶25、21∶27和19∶29)混合青贮,研究二者混贮60d时的化学组分和发酵品质,筛选出发酵品质最好的混贮比例,并对最优混贮料中的乳酸菌进行分离鉴定。结果表明,所有混贮组的pH值均显著低于玉米秸秆单贮组(P0.05),说明混合青贮品质优于单独青贮。混贮组中ME5组品质最佳,pH值和氨态氮/总氮显著低于其他混贮组(除ME4组外,P0.05),乳酸含量显著高于其他混贮组(除ME1组外,P0.05)。从ME5组中分离得到12株乳酸菌。分别为1株短乳杆菌(Lactobacillus brevis)、3株植物乳杆菌(Lactobacillus plantarum)、7株戊糖片球菌(Pediococcus pentosaceus)和1株肠道肠球菌(Enterococcus hirae)。ME5组中乳杆菌属和片球菌属为优势属,且以同型发酵乳酸菌为主。     

秸秆还田深度对土壤团聚体组成及有机碳含量的影响

为探究玉米秸秆还田至不同深度后对土壤团聚体及有机碳含量的影响,采用田间微区试验,将秸秆磨碎后分别还田至0～10、10～20、20～30、30～40 cm 4个深度土层,同时设置不还田对照,共计5个处理,连续种植玉米两年后采集土壤样品,采用湿筛法将团聚体分为>2、2～0.25、<0.25 mm共3个粒级,测定了土壤及团聚...     

响应面法优化玉米秸秆酶水解条件的研究

针对玉米秸秆制取燃料乙醇过程中玉米秸秆酶水解效率低的问题,利用响应面法对玉米秸秆酶水解条件进行优化。首先通过两水平Plackett-Burman试验中8个因素,筛选出3个对还原糖产率影响最大的因素(酶浓度、温度和固液比),再通过最陡爬坡试验确定其最优区域,然后通过Box-Behnken设计和响应面法进一步确定因素间相互关系和以还原糖最大产率为目标的最优条件。结果表明:酶浓度和固液比、温度和固液比间的交互作用对酶水解的影响显著,还原糖最大产率(42.97%)的最优条件为酶浓度55.45U.g-1,酶比例2∶1,温度44.39℃,pH值5.0,固液比1∶10.3,转速140r.min-1,酶解时间72h,Mg2+浓度0.01%。     

Identification of lactic acid bacteria isolated from corn stovers

One hundred and twenty‐six strains were isolated from corn stover in Henan Province, China, of which 105 isolates were considered to be lactic acid bacteria (LAB) according to Gram‐positive, catalase‐negative and mainly metabolic lactic acid product. Analysis of the 16S ribosomal DNA sequence of 21 representative strains was used to confirm the presence of the predominant groups and to determine the phylogenetic affiliation of isolates. The sequences from the various LAB isolates showed high degrees of similarity to those of the GenBank type strains between 99.4% and 100%. The prevalent LAB, predominantly Lactobacillus (85.6%), consisted of L. plantarum (33.3%), L. pentosus (28.6%) and L. brevis (23.7%). Other LAB species as Leuconostoc lactis (4.8%), Weissella cibaria (4.8%) and Enterococcus mundtii (4.8%) also presented in corn stover. The present study is the first to fully document corn stover‐associated LAB involved in the silage fermentation. The identification results revealed LAB composition inhabiting corn stover and enabling the future design of appropriate inoculants aimed at improving the fermentation quality of silage.     

低温产甲烷菌群对玉米秸秆低温厌氧消化的生物强化作用

为研究产甲烷菌群对秸秆低温厌氧消化的生物强化作用,试研究将长期驯化的低温产甲烷菌群投加至秸秆厌氧消化体系中,对比不同添加剂量(3%、6%、9%、12%、15%和18%)对低温(20℃)批式厌氧消化性能的影响。对产甲烷性能、中间代谢产物进行统计学和动力学分析,评价生物强化效果,确定最佳剂量,结合微生物群落分析揭示生物强化作用机制,结果表明：生物强化可促进秸秆低温厌氧消化,提高甲烷率1.27～2.24倍,促进乙酸和丙酸的降解,避免酸抑制,相比对照组缩短厌氧消化时间(T₈₀)12～19d;动力学分析表明：生物强化可缩短厌氧消化的延滞期;统计学分析表明：强化甲烷产量的最佳剂量为12%,单位质量菌群强化甲烷产量的最佳剂量为6%;微生物群落分析显示生物强化促进低温厌氧消化的主要原因是提高了产甲烷菌Methanothrix和Methanosarcina相对丰度。     

水热-乙醇提取处理玉米秸秆促进酶解效率

针对水热预处理不能明显移除木质素、木质素在较高温条件下从细胞壁中分解游离并重新聚合的特点, 采用水热-乙醇提取处理玉米秸秆, 与水热预处理的效果进行了对比, 并对乙醇过程进行了优化。结果表明:水热-乙醇提取能够移除部分木质素, 提高预处理后固体中纤维素含量以及纤维素的酶解效率, 水热-乙醇提取后秸秆的木质素移除率随水热预处理温度的增加而增大。乙醇提取的较优工艺条件是液固比25、室温、120 r·min^-1,提取10 h.经210 ℃、20 min预处理的秸秆再经乙醇提取后, 酸不溶木质素含量由30.5%下降为18.2%,纤维素含量由62.2%提高到73.6%,酶解率为93.2%(15 FPU·g^-1纤维素),酶解时间由48 h缩短至24 h.     

不同添加剂对不带穗玉米秸秆青贮发酵品质的影响

本试验主要探讨了糖蜜、植物乳杆菌和甲酸3种添加剂对不带穗玉米秸秆青贮发酵品质的影响。试验设对照组、糖蜜、植物乳杆菌和甲酸4个处理组。在发酵第1、3、7、15、30和60天分别开罐取样进行检测分析。结果表明,与对照组相比,3种添加剂都增大了不带穗玉米秸秆青贮发酵末期的pH和干物质含量,都提高了发酵过程中乳酸与乙酸的生成比例,但3种添加剂并没有提高玉米秸秆青贮饲料干物质消化率。     

玉米秸青贮和晒干过程中化学成分变化及碳水化合物组分发酵动力学

采用曲线相减法测定了鲜样、青贮和晒干处理玉米秸的碳水化合物组分变化及发酵动力学,以提供应用CNCPS模型的方法。结果表明:与鲜样相比,青贮和晒干处理均显著增加了中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)含量(P<0.01);青贮极显著增加了全样和组分B2的最大理论产气量(P<0.01),晒干则极显著增加了组分B2的最大理论产气量(P<0.01),但青贮和晒干使得组分A和组分B1的最大理论产气量极显著降低(P<0.01);青贮和晒干极显著降低了全样的产气速率(P<0.01),并极显著增加了全样的产气延滞期(P<0.01),但对组分A、组分B1和组分B2的产气速率及产气延滞期均无显著影响(P>0.05)。     

Cell morphology and chemical characteristics of corn stover fractions

This paper investigated cell morphology, chemical components, lignin distribution and inorganic elements distribution of corn stover fractions. Corn stover fractions, classified as stalk rind, stalk pith and leaf, had different tissues, cell morphology and chemical compositions. Corn stalk rind had good fiber morphological characteristics for papermaking, while stalk pith, having short fibers and high contents of parenchyma and vessel, was not suitable for papermaking. Stalk rind had the highest lignin and cellulose content but the lowest hemicellulose content among all the fractions. The major ash-forming elements in corn stover fractions were potassium, chlorine, silica, calcium, magnesium and sulfur. Potassium and chlorine took more than 86% of total inorganic elements in stalk rind while silica content was much higher in leaf and stalk pith than that in stalk rind. Perivascular sclerenchyma and subepidermal sclerenchyma of stalk rind were more lignified than the other tissues. The highest lignin concentration existed in cell middle lamella and corner. All corn stover fractions could be good biorefinery feedstock based on their main chemical compositions, though they are obviously heterogeneous in aspects of cell morphology and chemical characteristics.