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.

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.

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.

Corn Husk Fiber Preparation and Morphology with Alkali Treatment

The corn husks were usually discarded as useless materials,after alkali treatment from which the corn husk fiber was obtained. The corn husk fiber included half degumming corn husk bundle fiber and corn husk single fiber. This study found that corn husk single fiber was a kind of cellulose fiber,and was obtained with the fully alkali treatment technique,the process of which was NaOH concentration 0.15 g/mL,temperature at 80℃,and reaction time about 2.5 h. The morphologies of corn husk single fibers presented nature convolutions along with the fiber axis. They were closed at both ends,and they had a pentagram cavity and oval-shaped crosssection. They were flat shape,the fineness of the fibers was close to cotton fiber,and the mechanical properties of the fibers were similar to hemp fiber. So the corn husk fibers could be predicted that they could be used in textile industry because their properties were very close to cotton fiber or flax fiber.

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.

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%。

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。

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。

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%。

一种麦秸纤维替代木粉制备的景观用复材特性研究

为提高园林景观建筑材料的环保性、强度和耐水性等,试验以麦秸纤维代替传统木粉,并加入剑麻纤维,制备了一种木塑复合材料(WPC),并对其性能进行研究。试验结果表明,麦秸纤维可以代替木粉制备WPC,制备出的WPC力学性能相差不大;剑麻纤维的掺入,可以提升WPC的力学性能和耐水性;当掺20 phr麦秸纤维、5 phr长度5 mm的剑麻纤维时,试验制备的WPC材料弯曲、拉伸强度分别达到53.6、16.8 MPa,弯曲弹性模量为4200 MPa,吸水率低于7%,材料具备较好的强度性能,韧性和耐水性良好。试验制备的木塑复合材料综合性能良好,可以作为园林景观建筑材料实际应用。

利用近红外光谱测定玉米非淀粉组分中纤维素及半纤维素含量

玉米非淀粉组分是可再生的生物质资源,为实现玉米皮渣中纤维素及半纤维含量的快速检测,该研究以偏最小二乘法(PLS)建立数学模型,探讨一阶导数及二阶导数平滑等预处理对建模的影响,建立玉米皮渣中纤维素及半纤维素近红外分析模型。研究结果表明,纤维素模型的定标集和验证集相关系数为0.9806和0.9799,定标集标准偏差(SEE)与验证集标准偏差(SEP)分别为0.296323和0.307204;半纤维素模型的定标集和验证集相关系数分别为0.9732和0.9005,SEE与SEP分别为0.773057和0.798132。近红外光谱技术可快速、准确分析玉米皮渣纤维素及半纤维素的含量,可为玉米非淀粉组分高附加值利用提供理论依据。

纤维素酶法提取玉米麸皮多糖的工艺条件优化

玉米麸皮是玉米湿法加工的主要副产物,是良好的食用、药用植物多糖来源。以未脱脂玉米麸皮为原料,将经酶法去除淀粉和蛋白质后的皮渣采用复合纤维素酶法浸提玉米麸皮多糖(ECP),通过响应面法优化确定了酶法提取最佳工艺条件为:木聚糖酶∶复合纤维素酶=1∶1,加酶量1.5%(对底物),p H 4.1,底物浓度5g/100m L,酶解时间5h,酶解温度55℃,多糖得率为27.25%。玉米麸皮多糖主要组分的相对分子量为1720、911KDa,含有一定量的蛋白质和酸性糖以及微量的阿魏酸。

玉米膳食纤维在冰淇淋中应用的研究

本研究采用高压蒸煮法和挤压法对玉米膳食纤维进行处理,并对不同处理方法的玉米膳食纤维在冰淇淋中的应用特性进行了研究,通过正交试验分析,确定了适于加入冰淇淋中的玉米膳食纤维种类及其在冰淇淋中的最佳用量。试验结果表明:冰淇淋中添加6%的经挤压处理的玉米膳食纤维效果理想,且不增加冰淇淋稳定剂的用量。此时冰淇淋口感滑润细腻,膨胀率为98%,抗融性最好。

超临界CO_2萃取玉米皮纤维脂类物质的研究

采用超临界CO2流体萃取技术脱除玉米皮纤维中脂类物质。通过正交试验方法确定超临界CO2流体萃取的最佳工艺条件为:萃取压力30MPa、萃取温度45℃、萃取时间60min、CO2流量23L/h,脂类物质提取率为5.06%。萃取脂类物质后所得玉米皮纤维颜色乳白,风味纯正,脂肪含量低于0.3%,可作为低热量高膳食纤维食品的添加剂。

玉米膳食纤维在饼干中应用的研究

将玉米深加工副产物玉米皮经适当处理制得高品质膳食纤维,并用于高膳食纤维饼干的生产。通过正交试验,对影响高膳食纤维饼干品质的主要因素进行分析,确定了高膳食纤维饼干的最佳工艺及配方。结果表明:膳食纤维的处理方法对产品感官品质的影响最大,其次是膳食纤维粒度、膳食纤维用量、添加剂用量。玉米纤维经挤出处理,粒度为0.147mm,添加量为16%,疏松剂和乳化剂用量分别为0.4%和0.2%时,产品品质最好。

干玉米纤维饲料与羊草组合替代苜蓿干草对体外瘤胃发酵的影响

本试验旨在研究干玉米纤维饲料(DCFF)与羊草组合替代饲粮中的部分苜蓿干草对奶牛体外瘤胃发酵的影响。以奶牛饲粮为发酵底物,采用DCFF与羊草组合后分别等比替代底物中0、5.00%、10.50%、17.50%、22.90%的苜蓿干草,其中DCFF在底物中比例分别为0、3.00%、7.00%、11.00%和15.00%,分别命名为0DCFF、3DCFF、7DCFF、11DCFF、15DCFF组。测定体外发酵24 h的发酵参数、微生物区系及48 h的产气参数。结果表明:1)DCFF与羊草组合替代苜蓿干草对体外发酵产气量、潜在产气量和产气速率影响显著(P<0.05),均随着替代比例的增加而先升高后下降,其中11DCFF组最高;DCFF与羊草组合替代苜蓿干草对体外发酵干物质消失率的影响显著(P<0.05),11DCFF和15DCFF组显著高于其他各组(P<0.05)。2)DCFF与羊草组合替代苜蓿干草对发酵液微生物蛋白、氨态氮、乙酸、丙酸、丁酸和总挥发性脂肪酸浓度影响显著(P<0.05),均随着替代比例的增加而呈先升高后平缓的趋势;DCFF与羊草组合替代苜蓿干草对发酵液p H影响显著(P<0.05),随着替代比例的增加而呈先下降后平缓的趋势。3)DCFF与羊草组合替代苜蓿干草对发酵液黄色瘤胃球菌、产琥珀酸丝状杆菌、溶纤维丁酸弧菌的相对数量影响显著(P<0.05),均随着替代比例的增加呈先升高后平缓的趋势;发酵液牛链球菌、溶淀粉琥珀酸单胞菌、嗜淀粉瘤胃杆菌、白色瘤胃球菌的相对数量各组间无显著差异(P>0.05)。综上所述,利用DCFF与羊草组合替代奶牛饲粮中部分苜蓿干草有利于体外瘤胃发酵,其中替代17.50%和22.90%苜蓿干草的体外发酵效果较好,此时饲粮中DCFF的比例分别为11.00%和15.00%。

玉米膳食纤维在面包中的应用

采用高压蒸煮法和挤压法对玉米膳食纤维进行处理,研究了不同处理方法的玉米膳食纤维在面包中的应用特性,并通过正交试验分析,确定了适于加入面包中的玉米膳食纤维种类及其在面包中的最佳用量。结果表明:面包中添加7％的玉米膳食纤维(挤压法处理)效果理想,且不增加面包添加剂的用量。此时面包的口感优良,抗老化性较好。