Breakdown of Corn Fiber by a Metagenomic Ferulolyl Esterase in Combination with Glycosyl Hydrolases

A feruloyl esterase (FAE-C6) gene of 957 bp was isolated from rumen microbial metagenome, subcloned into pET32b vector, and expressed in Escherichia coli. The enzyme purified in active form, consisted of 319 amino acid residues, with a molecular weight of 43.7 based on SDS-PAGE. Homology modeling showed that the FAE contained the catalytic triad composed of Ser154-Asp263His295 and a classical Gly-X-Ser154-X-Gly nucleophile motif commonly found in esterases. The FAE-C6 was characterized using corn fiber as substrate. Its combining action with glycoside hydrolases (C, X, A) individually and in various combinations was studied with focus on the difference in the effects on FA and sugar release. Glycoside hydrolases with endo-xylanase included in the enzyme mixture showed significant impact on increasing the FA yield. For the release of sugar, FAE enhanced the yield in all hydrolase combinations moderately and endo-xylanase was not the key factor in the enzyme formulation.

Development of Kaolin and Glass Fiber Reinforced Composites for Thermal Insulating Panels

In our modern world, where conserving energy is highly valued, thermal insulation panels play a crucial role in reducing heat transfer between two spaces, surfaces, or materials. They are used to enhance the energy efficiency of various industrial applications by minimizing heat loss and temperature control. These panels function as silent protectors, aiding in reducing energy consumption and making things more sustainable and better for the environment. This is where composite materials come in;they are known for their lightweight nature, high strength-to-weight ratio, and excellent thermal insulation properties and have gained significant attention. Researchers are actively engaged in various studies aimed at enhancing these materials further. This research project focuses on the development of kaolin and glass fiber-reinforced composites for thermally insulating panels, to which natural strengthening materials like corn husk and bamboo fibers are added. The aim is to create cost-effective and efficient composite materials for thermal insulation applications by incorporating these components with a binder consisting of potassium silicate, hydroxide, and distilled water. This project involves conducting compression tests, bending tests, impact tests, thermal conductivity measurements, and microscopic analysis to evaluate the mechanical and thermal properties of the developed composites. The profound impact of these engineered composites on thermal insulation panels stands to revolutionize energy conservation efforts, offering a potent avenue to minimize heat loss and enhance overall energy efficiency across an array of industrial sectors.

Replacement of Forage Fiber Sources with Dried Distillers Grains with Solubles and Corn Germ Meal in Holstein Calf Diets

This study was carried out to determine the effect of replacement of forage fiber sources from alfalfa and Leymus chinensis with nonforage fiber sources（NFFS） from dried distillers grains with solubles and corn germ meal on calves growth, rumen development and blood parameters. 48 female and 12 male calves（（110.55±15.36） kg of body weight and 12 wk of age） were assigned randomly to four dietary treatments（15 calves/treatment） in a completely randomized design. Experimental diets were： 0% NFFS（control）, 9% NFFS（group 1）, 18% NFFS（group 2）, 27% NFFS（group 3）, and contained equivalent neutral detergent fiber and total digestible nutrients, respectively. The dry matter intake was similar among diets, averaging 3.33 kg d-1, and no differences were detected for body weight, withers height, body length and heart girth. In addition, the development of rumen, reticulum, omasum and abomasum also were similar among diets. Dry matter, crude protein, and neutral detergent fiber digestibilities increased with the increasing levels of NFFS in the experimental diets, but had no significant effect. Blood urea nitrogen, total protein and glubulin were not affected by the dietary treatment, but group 3 resulted in the highest（P〈0.05） concentrations of glucose and the lowest（P〈0.05） concentrations of triglycerides and albumin. In conclusion, dried distillers grains with solubles（DDGS） and corn germ meal（CGM） were available and alternative fiber sources for Holstein calf diets.

Effects of NaOH Treatment on Fiber, Crude Protein and Soluble Sugar Content of Corn Straw

[Objective] The paper was to study the effects of different levels of NaOH on fiber, crude protein and soluble sugar content of cornstraw. [Method] Four treatments were designed in the test, namely control group, group 1, group2 and group 3, which were added with 0, 2%, 3%and 4% NaOH according to the dry weight of corn straw, and the moisture of corn straw after treatment was 45%. After being treated at room tem-perature for 48 h, sensory evaluation and nutrient composition analysis were performed for each group, and the contents of neutral detergent fiber（NDF）, acid detergent fiber （ADF）, crude protein （CP） and soluble sugar （SS） were measured. [Result] With the increasing addition level of NaOH,the content of NDF and ADF decreased gradually, and significant differences were observed between group 3 （adding 4% NaOH） and control group（P〈0.05）. There was no significant difference in CP content among treatment groups（P〉0.05）; the SS content gradually increased, and there weresignificant differences between treatment groups and control group （P〈0.05）. [Conclusion] 4% NaOH reduced the fiber content and increased thesoluble sugar content of corn straw.

玉米须不溶性膳食纤维分析及其对面包品质和消化特性的影响研究

首先分析玉米须不溶性膳食纤维(corn silk insoluble dietary fiber,CSIDF)的组分和物理特性,再研究其添加量及粒径对面包比容、色泽、质构、孔隙度、感官等品质和消化特性的影响。结果表明,其主要含80.64%膳食纤维和10.15%蛋白质,以及少量的灰分和脂肪,主要由50.41%纤维素和28.80%半纤维素组成,具有良好的持水、持油和膨胀特性,且粒径越大,3种特性越好;添加玉米须不溶性膳食纤维后面包比容减小,色泽加深,硬度增大,孔隙度降低,不同CSIDF添加量及粒径间存在差异,面包品质与CSIDF添加量及粒径基本呈现负相关,综合分析确定粒径最小的D_(1)(平均粒径为24.91μm)最适宜添加,其添加量为3%时较合适;体外消化试验表明,CSIDF可以通过降低面包中RDS含量、提高SDS和RS含量来延缓淀粉的消化吸收,维持血糖稳定。

一种新型纤维素基包装材料的研制与应用设计

针对生物可降解包装材料的高成本、性能低等问题,制备一种以黄麻纤维、粘胶纤维和聚乳酸玉米纤维为主要原料的的纤维素基包装材料,并对其力学性能进行探究。结果表明,热压处理有利于增强纤维抱合性,从而增加材料的稳定性;黄麻/粘胶/玉米纤维最佳配比方案为50∶35∶15,此时,制备的复合包装材料的纵向断裂强力为212.35 N,横向断裂强力为126.78 N,纵向撕破强力为29.26 N,横向撕破强力为13.06 N,顶破强力为77.61 N。试验制备的黄麻/粘胶/玉米纤维素基包装材料不仅成本低、绿色环保,还具备较好的力学性能,能作为一种生物可降解包装材料应用于实际生活中。

玉米秸秆-轮胎钢丝混杂纤维混凝土的抗压性能和抗冻性能研究

通过在混凝土中添加不同掺量的玉米秸秆纤维和轮胎刚丝纤维,分析了玉米秸秆纤维和废旧轮胎钢丝纤维的掺量对混凝土7 d和28 d的立方体抗压强度的影响,同时也进行了抗冻性试验。研究表明:在适量的纤维掺量下,玉米秸秆纤维和轮胎钢丝纤维对混凝土7 d和28 d的立方体抗压强度都具有提升效果,最优组掺量为0.6%的玉米秸秆纤维,1.0%的轮胎钢丝纤维,抗压强度分别比基准组提高了8.78%和15.92%;两种纤维的掺入也提高了混凝土的抗冻性,最优组较基准组在冻融循环25、50、75次时的损失率分别降低3.63%、4.46%、7.31%。

半纤维素对玉米秸秆皮Lyocell纤维性能的影响

探讨了半纤维素对Lyocell纤维制备时溶浆过程以及纺丝过程的影响,研究了半纤维素对Lyocell纤维的力学、抗原纤化和染色等性能的影响。试验可知:使用市售质量分数50%的NMMO溶剂在90℃温度下即可完全溶解玉米秸秆皮浆粕;半纤维素含量较高的玉米秸秆皮浆粕的流动性更好,制成的Lyocell纤维的染色性能和抗原纤化性能更好,断裂伸长率较大,结晶度较小。

Continuous succinic acid production from corn fiber hydrolysate by immobilized Actinobacillus succinogenes in a hollow fiber membrane packed‑bed biofilm reactor

Succinic acid is one of the most useful intermediate chemicals that can be produced in a biorefinery approach.In this study,Actinobacillus succinogenes was immobilized to produce succinic acid using non-detoxified corn fiber hydrolysate(CFH)and a control mimicking the sugars in CFH.Tests were carried out in a hollow fiber membrane packed-bed biofilm reactor(HFM–PBR)operated in a continuous mode.Under steady-state conditions,the bioconversion process was characterized in terms of sugar consumption,succinic acid and other organic acid production.Steady states were obtained at dilution rates of 0.025,0.05,0.075,0.1,0.2,and 0.3 h^(-1).The optimal results were achieved at the dilution rate of 0.05 h^(-1)and recirculation rate of 50 ml/min with a maximum succinic acid concentration,yield and productivity of 31.1 g/L,0.61 g/g and 1.56 g/L h,respectively,when control was used.Succinic acid concentration,yield and productivity of 23.4 g/L,0.51 g/g and 1.17 g/L h,respectively,were obtained when CFH was used.Productivity in the HFM–PBR was between 1.3 and 1.9 times higher than productivities for succinic acid production from CFH stated in the literature.The results demonstrated that immobilized A.succinogenes has the potential for effective conversion of an inexpensive biomass feedstock to succinic acid.Furthermore,the process has the potential to serve as a means for value-added chemical biomanufacturing in an integrated corn biorefinery.

基于热膨胀微球发泡的废纸纤维/淀粉复合发泡材料性能的研究

本研究以玉米淀粉(CS)和数字印刷废纸纤维(DPWPF)为基材,热膨胀微球(EHM204)为发泡剂,采用加热烘焙方式制备DPWPF/CS复合发泡材料,研究了DPWPF含量对DPWPF/CS复合发泡材料各项性能的影响。结果表明,在DPWPF/CS复合发泡材料的制备中,EHM204可作为发泡剂,适量DPWPF的加入,能够改善淀粉基发泡材料的力学性能,当DPWPF含量为15%(相对于CS质量)时,制备的发泡材料的综合性能最佳,密度为0.66 g/cm^(3),发泡率为70%,硬度为70.00 HC,弹性比能为14.25×10^(4)J/m^(3),缓冲系数为4.21,回弹率达95.1%。

复合酶改性玉米皮可溶性膳食纤维的工艺优化及理化特性分析

为探究玉米皮可溶性膳食纤维(Soluble Dietary Fiber,SDF)最佳提取工艺及功能特性。本研究以玉米加工副产物玉米皮为原料,采用复合酶法改性提取玉米皮可溶性膳食纤维,通过单因素实验和响应面优化确定最佳工艺参数并对其理化性质进行了研究。结果表明,当纤维素酶添加量为1.5%、木聚糖酶添加量为1%、酶解温度为55℃、酶解时间为150 min时,玉米皮SDF得率达到的最高值为16.64%±0.21%,其溶解度为87.63%±0.43%,持水力为2.87±0.16 g/g,持油力为2.30±0.12 g/g,葡萄糖吸附力为5.32±0.12 mmol/g,体外模拟胃环境(pH2.0)、肠环境(pH7.0)下胆固醇吸附性分别为11.74±0.15、42.93±0.08 mg/g,胆酸钠吸附性分别为15.43±0.17、50.67±0.10 mg/g。研究结果可为玉米皮可溶性膳食纤维的开发利用提供理论参考。

玉米植株不同部位的青贮特征及其品质提升策略

玉米因其高产量、高干物质、高纤维、高淀粉、高代谢能和适宜青贮的特点,近年来在其适栽区域作为发展草食畜牧业的青贮饲料愈发受到重视。玉米秸秆富含纤维,籽粒富含淀粉,高纤维和高能量兼具的营养特性让全株玉米成为从谷物密集要肉奶逐步转向饲草密集要肉奶的首选栽培饲用作物。同时,其植株各部位可分别青贮的特性使得玉米青贮独树一帜。本文基于秸秆青贮、果穗青贮、高湿玉米青贮、籽粒复水青贮、全株玉米青贮的近期研究进展,论述玉米不同部位的青贮特征和应用场景,并总结玉米纤维与淀粉消化率的主要影响因素及其提升策略,进而展望中国玉米青贮的未来发展方向。

复合酶法玉米苞叶纤维脱胶工艺研究

为拓展玉米苞叶的精深加工、提升玉米苞叶纤维的应用价值,采用复合酶对玉米苞叶脱胶,以质量损失率和残胶率为响应值,探究木聚糖酶、果胶酶和漆酶组成的复合酶系对玉米苞叶脱胶的最佳工艺。采用光学显微镜观察胶质的脱除和纤维表面的形态。研究结果表明:复合酶最佳脱胶条件为:木聚糖酶0.2 g/L、果胶酶0.3 g/L、漆酶0.1 g/L,酶处理时间为48 h,pH值为4.6,料液比为1∶50,酶处理温度为45℃;在此条件下,玉米苞叶纤维的质量损失率为45.52%,残胶率为50.22%;复合酶脱胶后的玉米苞叶纤维表面较为光滑平整,纤维上没有胶杂质黏附。

玉米秸秆膳食纤维改性工艺优化及其功能特性评价

为提高玉米秸秆中可溶性膳食纤维含量(SDF),改善其功能特性,本研究在碱蒸汽处理的基础上,采用单因素和响应面设计优化酶解条件对SDF提取率的影响。通过扫描电镜(SEM)、持水力(WHC)、持油力(OHC)、溶胀力(WSC)、溶解性(WS)和葡萄糖吸附能力(GAC)的测定对比分析玉米秸秆、改性玉米秸秆、SDF和IDF的形态结构及理化特性。结果表明:最佳酶解条件为纤维素酶添加量15 FPU/g秸秆、酶解时间16 h,改性玉米秸秆中SDF含量达到9.94%,与未改性玉米秸秆相比提高285.27%。通过SEM观察,改性玉米秸秆和IDF的裂缝较多;SDF表面光滑,无明显裂缝。与未改性玉米秸秆相比,经碱蒸汽-酶法改性后玉米秸秆的WHC、OHC、WSC、WS、GAC分别提高了147.87%、134.95%、27.89%、62.44%和166.67%(P<0.05)。由此可见,碱蒸汽-酶法可以有效改性玉米秸秆膳食纤维,改性后其SDF提取率及综合特性得到明显提升。

玉米秸秆浆粕溶剂法纺丝技术

为探究玉米秸秆的应用,采用无氧蒸煮法将玉米秸秆茎皮粉末制成玉米秸秆浆粕,再以N-甲基吗啉-N-氧化物(NMMO)为溶剂溶解玉米秸秆浆粕制成纺丝液,最后将纺丝液纺制成玉米秸秆Lyocell纤维。采用流变仪对纺丝液进行了测试,试验表明:纺丝液为假塑性非牛顿流体。采用强伸度仪、X射线衍射仪、扫描电镜等表征了玉米秸秆Lyocell纤维的力学性能、结构和表观形态,并将其与传统的木浆Lyocell纤维进行比较,结果显示:玉米秸秆Lyocell纤维的拉伸强度达到行业标准,断裂伸长率低于行业标准;玉米秸秆Lyocell纤维的结晶度要比木浆Lyocell纤维的低5.4%;玉米秸秆Lyocell纤维表面光滑,无沟槽等缺陷,其外观与木浆Lyocell纤维的基本一样。

玉米秸秆不同部位化学组成及纤维形态分析

本研究以玉米秸秆皮、髓、叶、鞘部位为研究对象,通过多种手段对玉米秸秆不同部位的化学组分及纤维形态进行分析研究。研究结果表明,玉米秸秆全秆纤维束含量为51.19%,杂细胞含量高。其中,玉米秸秆皮中纤维束含量最多,占全秆纤维束的47.96%,α-纤维素含量为36.99%;叶和鞘纤维束含量占比分别为22.33%、23.65%;髓纤维束含量最少,为6.06%;秸秆皮纤维数均长度为1.17 mm,长宽比最大,为80.41,髓部纤维最短,对全秆纤维贡献率最低。

玉米粉和纤维复合酶对柠条锦鸡儿青贮品质的影响

试验旨在探究添加玉米粉和纤维复合酶对柠条锦鸡儿青贮品质的影响。以盛花期柠条锦鸡儿为青贮原料,采用单因素试验设计,共设置4组,分别为无添加的对照组(CK组)、添加10%玉米粉组(C组)、添加0.05%纤维复合酶组(F组)及添加10%玉米粉+0.05%纤维复合酶组(CF组),每组6个重复。青贮60 d,测定柠条锦鸡儿青贮的养分含量和发酵品质。结果显示,与CK组相比,C组青贮饲料的粗蛋白质和可溶性碳水化合物的含量均显著升高(P<0.05),C组和F组青贮饲料的中性洗涤纤维含量显著低于CK组(P<0.05),C组、F组和CF组青贮饲料的酸性洗涤纤维的含量均显著低于CK组(P<0.05),其中C组的中性洗涤纤维和酸性洗涤纤维含量最低,分别为52.64%及37.64%。C组、F组和CF组青贮饲料的相对饲喂价值均显著高于CK组(P<0.05),C组和CF组青贮饲料的总可消化养分极显著高于CK组(P<0.05)。与CK组相比,F组和CF组青贮饲料的pH值显著降低(P<0.05),乳酸含量显著提高(P<0.05);C组、F组、CF组青贮饲料的氨态氮/总氮、丙酸含量显著降低(P<0.05),C组的氨态氮/总氮、丙酸含量均为最低,分别为1.38%及0.66%;C组、F组和CF组青贮饲料的乳酸菌数量显著高于CK组(P<0.05),酵母菌数量显著低于对照组(P<0.05),各组均未检测到霉菌。各组青贮饲料V-Score评价等级均为良好,评分排序为C组>F组>CF组>CK组。研究表明,添加玉米粉和纤维复合酶可以改善柠条锦鸡儿的营养成分和发酵品质,单独添加10%的玉米粉对改善柠条锦鸡儿青贮品质的效果较好。

复合菌种发酵玉米秸秆的效果评定及筛选

试验以不同复合菌种发酵后的玉米秸秆作为发酵底物,进行瘤胃体外发酵试验并测定相关指标,结合各指标以筛选出最优的复合菌种。试验分为对照组(CON)、黑曲霉菌+地衣芽孢杆菌组(HD)、地衣芽孢杆菌+黄孢原毛平革菌组(DB)、黑曲霉菌+黄孢原毛平革菌组(HB),每个处理组3个重复,于室温下密封发酵21 d后开袋取样,通过感官鉴定和发酵指标评定,并采用瘤胃体外发酵方法,测定产气参数、发酵参数和体外消化率等指标,评价不同复合菌种对玉米秸秆的发酵效果。结果表明,HB、DB组的粗纤维、中性洗涤纤维、酸性洗涤纤维含量均显著低于CON组(P<0.05)。HB组合中酸性木聚糖酶、β-葡萄糖苷酶的活性较CON组显著提高(P<0.05)且高于其他各组。DB组合中外切β-1,4-葡聚糖酶、滤纸酶的活性较CON组显著提高(P<0.05)且高于其他各组。在瘤胃体外发酵试验中,DB组的产气量显著高于CON、HB组(P<0.05)。3个试验组的总挥发性脂肪酸含量显著高于CON组(P<0.05),其中DB组显著高于其他组(P<0.05)。DB组的酸性洗涤纤维体外消化率显著高于CON组(P<0.05),3个试验组的干物质体外消化率、粗蛋白体外消化率、中性洗涤纤维体外消化率均显著高于CON组(P<0.05),且DB组的中性洗涤纤维体外消化率显著高于其他组(P<0.05)。综上,本试验选用的复合菌种发酵均可不同程度提高玉米秸秆中各营养物质消化率和粗纤维降解率,综合分析,以玉米秸秆中接种5%地衣芽孢杆菌+5%黄孢原毛平革菌组合最优。

多菌种固态发酵玉米皮制备菌体蛋白饲料

以发酵和淀粉制糖工业产生的高粗纤维含量玉米皮为原料,通过多菌种固态发酵,降低玉米皮中粗纤维含量,增加发酵产物中蛋白含量,制备菌体蛋白生物发酵饲料。根据底物特点和产物目标选择适宜菌种进行发酵组合,采用单因素试验设计探究菌种比例、接种量、发酵方式、糖蜜含量及氮源种类对发酵产物中粗蛋白、真蛋白和粗纤维的影响。结果表明:最佳菌种比例为枯草芽孢杆菌CGMCC 1.7417∶枯草芽孢杆菌CICC 10090∶酿酒酵母CICC 32236∶产朊假丝酵母CGMCC 2.2878等于1∶1∶2∶2;种子液接种量为15%;最佳发酵方式为浅盘发酵;最佳糖蜜含量为10°Brix;最佳氮源种类为硫酸铵。玉米皮经多菌种固态发酵后,粗蛋白含量为21.38%,提升率32.47%;真蛋白含量为10.77%,提升率50.42%;粗纤维含量为17.78%,降低率14.19%。

复合菌剂对玉米秸秆发酵品质的影响

试验旨在筛选适用于微贮玉米秸秆的最佳益生菌组合。选取6种菌剂(地衣芽孢杆菌、枯草芽孢杆菌、粪肠球菌、凝结芽孢杆菌、酒酵母和米曲霉)设置A组至H组8个菌种组合。枯草芽孢杆菌、地衣芽孢杆菌、凝结芽孢杆菌、粪肠球菌在秸秆中的添加量为0.275%,酿酒酵母和米曲霉的添加量分别为0.05%、0.005%,对照组为不添加任何菌剂的I组。发酵10d后测定各组秸秆的营养成分。结果显示:与I组相比,不同菌种组合能够显著降低发酵玉米秸秆pH值和中性洗涤纤维(NDF)含量(P<0.05),效果最好的是E组。研究表明,不同菌种组合能够有效提高玉米秸秆饲料品质。