多菌种混合发酵稻草生产蛋白饲料的研究

以稻草为原料,利用酵母菌和真菌混合发酵生产蛋白饲料,试验表明：单纯通过产纤维素酶菌的培养对富集蛋白的效果并不显著,而经产纤维素酶菌与酵母菌混合发酵可大幅提高产品的蛋白质含量。本试验选用2株真菌、3株酵母与白地霉共培养,发酵后产物中蛋白质含量提高了2倍,并含有多种氨基酸,纤维素、半纤维素降解率分别为29.49%,17.58%。     

利用番茄废渣混菌固体发酵生产蛋白饲料

以番茄废渣为原料,以绿色木霉、黑曲霉、产朊假丝酵母、热带假丝酵母为出发菌种,通过单菌种和混菌种固体发酵实验,筛选出发酵产品蛋白质含量最高的菌种组合。实验结果表明,当绿色木霉∶黑曲霉∶热带假丝酵母=1∶2∶6时,发酵产品干物质中蛋白质含量高达35.00%,是较好的发酵组合。     

固定化根霉和酵母共用生产低度酒

酵母和根霉是生产小曲酒的主要微生物。本文研究了根霉和酵母两种固定化细胞共用的比例及边糖化边发酵的工艺条件,并进行了半连续发酵实验。在以米粉为主的液体培养基中发酵48小时,产酒为2.55%(V/V),原料出酒率达158.1%,产品具有典型的米香型。电子显微镜观察表明:根霉和酵母在发酵过程中生长良好,且菌体保持较长的稳定期,可以不断进行发酵。     

根霉酒精发酵特性的研究

本文对以2-2根霉等几株纯根霉作糖化发酵剂酿酒, 与2-2根霉和活性干酵母混合制曲酿酒作对照,对发酵过程中化学成分的变化规律进行了对比研究。结果表明:用纯根霉产酒精的发酵性能前期虽比加了酵母的根霉曲发酵更迟缓,但2-2菌株发酵结束时酒醪中的酒精含量与对照无显著差异。     

多菌混合发酵产纤维素酶及生物法预处理秸秆的研究

对实验室分离筛选的3株绿色木霉和6株枯草芽孢杆菌的生长及产酶情况进行了研究,综合确定绿色木霉绿2与芽孢杆菌S3为混合菌中产纤维素酶酶活最高的组合。在此基础上,采用解脂假丝酵母处理高粱秸秆。先将解脂假丝酵母的种子培养液按照3%的接种量接种到发酵产酶培养基中,隔24 h将绿色木霉绿2的孢子悬浮液按照2.67%的接种量接种到发酵产酶培养基中,再隔12 h将芽孢杆菌S3的种子培养液按照5.33%的接种量接种到发酵产酶培养基中,测定出的滤纸酶活（FPA）最高,为389.89 U/mL,比优化前提高了14.30%。     

响应面法优化深黄被孢霉产油突变株的发酵培养基配方北大核心CSCD

为了优化深黄被孢霉突变株的发酵培养基,在单因素实验基础上,采用响应面法(RSM)对深黄被孢霉产油突变株发酵培养基配方进行优化。结果表明,深黄被孢霉产油突变株最佳发酵培养基配方为:葡萄糖90.29 g/L,酵母膏4.14 g/L,Mg SO40.96 g/L,KH2PO41.99 g/L,p H 6.0。在最佳条件下油脂产量为12.01 g/L,比优化前(6.22 g/L)提高了93.09%。     

新疆伊犁地区发酵驼乳中酵母菌多样性分析

从新疆伊犁地区采集到12份发酵驼乳样品,用传统分离培养方法从中分离出35株酵母菌。通过生化鉴定结合形态观察,结果显示:8株为马克斯克鲁维酵母;15株属于单胞酿酒酵母菌;9株林德纳克勒克酵母;2株酿酒酵母;1株白地霉,其中单胞酿酒酵母菌是优势菌属。通过样品酵母菌26S r DNA基因D1区DGGE图谱的优势条带有12条;样品间酵母菌种群结构相似性系数范围21.9%～73.9%;Shannon-Wiener指数在1.92～3.41之间,丰度S值在10～34;在40%水平上样品聚为4类。酵母群落组成主要包括马克斯克鲁维酵母、酿酒酵母、单胞酿酒酵母菌、解脂耶氏酵母和白地霉等。     

响应面法优化深黄被孢霉产油突变株的发酵培养基配方

为了优化深黄被孢霉突变株的发酵培养基,在单因素实验基础上,采用响应面法(RSM)对深黄被孢霉产油突变株发酵培养基配方进行优化。结果表明,深黄被孢霉产油突变株最佳发酵培养基配方为:葡萄糖90.29 g/L,酵母膏4.14 g/L,Mg SO40.96 g/L,KH2PO41.99 g/L,p H 6.0。在最佳条件下油脂产量为12.01 g/L,比优化前(6.22 g/L)提高了93.09%。     

传统发酵霉豆渣中微生物的分离及其作为豆渣发酵剂的应用

豆渣是大豆加工的副产品,具有产量大但应用不足的特点。为提高豆渣的利用率,开发新型豆渣产品。该实验对湖南邵阳霉豆渣进行微生物分离,旨在得到能利用豆渣营养物质的菌株。共分离33株菌,分别为乳酸菌13株,戊糖乳杆菌（Lactobacillus pentosus）、乳酸片球菌（Pediococcus lolii）、短乳酸杆菌（Lactobacillus brevis）、发酵乳杆菌（Lactobacillus fermentum）、融合魏斯氏（Weissella confusa）;芽孢杆菌7株,枯草芽孢杆菌（Bacillus subtilis）、贝莱斯芽孢杆菌（Bacillus velezensis）;葡萄球菌9株,松鼠葡萄球菌（Staphylococcus sciuri）、克氏葡萄球菌（Staphylococcus kloosii）、鸡葡萄球菌（Staphylococcus gallinarum）、缓慢葡萄球菌（Staphylococcus lentus）;2株酵母菌,库德毕赤酵母（Pichia kudriavzevii）、白地霉（Geotrichum candidum）;2株霉菌,总状横梗霉（Lichtheimia ramosa）和伞房横梗霉（Lichtheimia corymbifera）。用白地霉、总状横梗霉和伞房横梗霉固态发酵豆渣,结果表明,发酵豆渣总酚和抗氧化活性明显高于未发酵的豆渣（p<0.05）,发酵6 d,ABTS清除率和总酚含量达到最高,为92.67%和134.35 mg GAE/10 g,DPPH清除率为79.98%。证实发酵豆渣可提高豆渣营养价值,有助于豆渣在食品及其副产品的应用。     

酵母菌与乳酸菌共培养发酵马铃薯渣的研究

选用4株酵母菌和2株乳酸菌固态发酵马铃薯渣,通过测定发酵产物粗蛋白和真蛋白含量变化情况,确定酵母菌与乳酸菌的共生关系,最终筛选生产SCP(单细胞蛋白)的适宜菌种组合。实验结果表明,适宜的菌株配伍为酿酒酵母+白地霉+热带假丝酵母+植物乳杆菌,经过发酵,马铃薯渣粗蛋白含量为35.63%,真蛋白含量为14.05%。     

柑橘废渣生产单细胞蛋白饲料研究

以柑橘废渣为原料生产单细胞蛋白饲料,采用Plackett-Burman实验设计法分析筛选主要影响因素,然后采用中心组合设计方法考察其交互作用对单细胞蛋白饲料的真蛋白含量的影响规律及相应的响应分析图,并预测最优化发酵条件。实验结果表明:发酵温度,接种量及尿素添加量,且影响程度为尿素>发酵温度>接种量,当发酵温度为30.1℃,接种量为14.4%,尿素添加量为1.8%时,柑橘废渣生产单细胞蛋白饲料真蛋白含量最大。该工艺有效利用了柑橘废渣,并获得了真蛋白含量较高的单细胞蛋白饲料。     

一种组织蛋白即食膨化食品的风味优化研究

大豆组织蛋白食品具有较好的营养和吸收效果。该文通过单因素试验和响应面分析研究食盐、白砂糖和白醋添加量对一种添加蛋白肽的组织蛋白即食膨化食品风味以及质构的影响,并对配方进行了优化。经优化调整后,确定最优配方为食盐添加量5.7%,白砂糖添加量6.7%,白醋添加量3.0%,此条件下产品感官品质最佳,感官评分为86分,适合佐餐食用。所得制品的弹性、咀嚼性、内聚性、胶黏性和硬度分别为：4.47 mm、4.88 mJ、0.78%、1.12 N、1.25 N。     

挤压花生蛋白品质特性的加工因素研究

基于Box-Behnken响应面模型,研究花生蛋白挤压过程中挤压参数（机筒温度、螺杆转速、物料水分）对产品品质（膨胀率、吸水性指数、氮溶解指数、硬度）的影响,并根据标准型原理分析单因素对产品品质的贡献率。结果表明,随着机筒温度、螺杆转速、物料水分的上升,产品膨胀率不断增加;机筒温度和螺杆转速对产品的吸水性指数影响显著;高温、高湿、高剪切力使产品的氮溶解指数和硬度处于较低的水平。利用转化为标准型的回归方程计算出机筒温度对膨胀率的贡献率为59.3%,螺杆转速对硬度贡献率为54.5%。物料水分对吸水性指数和氮溶解指数具有决定性的作用。通过调整挤压操作参数,可以一定范围内控制挤压蛋白产品品质。     

挤压蒸煮对豆粕体外消化率的影响

以脱脂豆粕为原料,采用双螺杆挤压技术,研究了喂料速度、物料含水量、螺杆转速、挤压温度对蛋白质消化率的影响,在单因素试验的基础上,通过正交试验确定出了豆粕最佳的挤压工艺条件。结果表明:影响消化率的主要因素是挤压温度和物料含水量,而喂料速度与螺杆转速影响较小。豆粕挤压蒸煮的最佳工艺条件是:喂料速度0.35 kg/min、物料含水量33%、螺杆转速130 r/min、挤压温度150℃,在该工艺条件下,消化率达到95.7%,比原始豆粕消化率提高12.1%。     

Effect of Karnal Bunt Disease on the Milling, Rheological and Nutritional Properties of Wheat: Studies on Some Chemical Constituents and Biological Effects

The effect of Karnal bunt disease at 1,3,5, and 10% level of diseased grain infection on trimethylamine content, phenolic acids was found to increase with progressive increase in disease infection. Aflatoxin was absent in both healthy and infected wheats. Rat feeding with different percentages of Karnal bunt-infected diets showed no adverse effect on the feed acceptability. Rather, animals fed diets having 5 and 10% infected wheat showed higher feed intake. Diets having 10% infected wheat resulted in reduced liver weight, white blood cell, and monocyte counts.     

Effects of Altering Milk Production and Composition by Feeding on Multiple Component Milk Pricing Systems

Data representing 1105 cows were obtained from published scientific reports to estimate the extent to which changes in feeding may affect the composition of milk and the production of milk protein and milk fat. Changes in milk pricing systems were also related to dairy cattle feeding practices that dairy producers may profitably implement. Regression equations were derived to estimate the transfer of gross energy in feed and gross energy in crude protein of feed into milk fat and milk protein. Feeding rations that contained 59% concentrate increased dry matter and crude protein intakes compared to feeding rations that contained 49% concentrate. Feeding higher energy rations also resulted in increased production of milk, milk fat, and milk protein and returned a greater profit over feed costs when milk was priced using each of four milk pricing systems. An increase in milk production, rather than a change in composition of milk components, accounted for most of the economic gain.     

Effect of post-induction substrate oscillation on recombinant alkaline phosphatase production expressed in Escherichia coli

Microorganisms are exposed to fast changes in microenvironment in large scale bioreactors. Because of their fast response to the changes, overall performance of biological system in small scale differs from large scale. Hence the variations in the environment that microorganisms are living in are mimicked in small scale. For this purpose one way is to feed substrate into the bioreactor in an oscillatory profile. In this work two different types of triangular oscillatory feeding profiles were applied as the post induction feeding strategy in intracellular recombinant alkaline phosphatase production expressed in Escherichia coli to find out if this biological system behaves in inhomogeneous environment differently. On line and offline measurements provide evaluation of product quality and quantity. Then the results of the experiments were compared with those of the control run at which constant feeding rate was executed. The results showed that oscillatory feeding at which cells were not starved led to higher yield of protein per substrate (0.027 C-mol/C-mol) and higher activity per protein (0.79 U/mg) when compared to a constant feeding rate (0.011 C-mol/C-mol and 0.11 U/mg).     

Short communication: Effect of feed barrier design on the behavior of loose-housed lactating dairy cows

The objective of this study was to evaluate the effects of 2 feed barrier systems on feeding and social behavior of dairy cows. Forty-eight lactating Holstein cows were subjected to each of 2 treatments in a cross-over design. The treatments were 2 types of feed-line barriers: 1) post-and-rail, and 2) headlock. Time-lapse video was used to quantify the feeding behavior and incidence of aggressive displacements of the cows at the feed bunk. Average daily feeding time did not differ when cows used the headlock barrier compared with the post-and-rail barrier. However, there were certain changes in feeding time during periods of peak feeding activity: cows that had lower feeding times relative to group mates when using the post-and-rail barrier showed more similar feeding times to group mates when using the headlock barrier. There were 21% fewer displacements at the feed bunk when cows accessed feed by the headlock barrier compared with the post-and-rail barrier. These results suggest that using a headlock barrier reduces aggression at the feed bunk and improves access to feed for socially subordinate cows during peak feeding periods.     

Nonpolluting Conversion of Whey Permeate to Food Yeast Protein

By using concentrated whey permeate as substrate, food grade yeast (Kluyveromyces fragilis) was grown continuously in the fermentor to very high cell densities (total broth dry weight of over 140 g/L). The high ash content in whey permeate was not inhibitory to cell growth. Cell mass yield remained about constant at pH range 3.9 to 5.1, temperatures between 31 to 37°C, with 6 to 30% whey permeate solids in the feed. Dilution rate (.1 to .3 h⁻¹) had little effect on the cell mass yield. At temperatures higher than 38°C, yield decreased. The high cell density fermentation broth was direct-dried without centrifugation and washing and the composition of the direct-dried product was determined. Amino acid profile, vitamin content, and fatty acid composition indicated a quality protein product suitable for food or feed supplementation. Ash content of the product was higher than other dried yeasts because of the high mineral content in whey permeate. Ash content could be significantly reduced by the addition of a small portion of another inexpensive fermentable sugar to the whey permeate feed. With this addition, cell mass yield, productivity, and protein content of the product increased. Because this high cell density, direct-dry process did not require preconcentration of the fermentor broth to dry the product economically, it did not generate a waste stream that required further treatment. This process converts waste whey permeate to useful food protein and essentially eliminates potentially polluting waste streams.     

Assessment of antibacterial properties and the active ingredient of plant extracts and its effect on the performance of crucian carp (Carassius auratus gibelio var. E'erqisi,Bloch)

BACKGROUND: In this study, the antibacterial properties and active ingredient of plant extracts and its effect on the performance of crucian carp (Carassius auratus gibelio var. E'erqisi, Bloch) were assessed. RESULTS: The transmission electron microscopy and flow cytometric analysis showed that the antibacterial activity of plant extracts is due to the disruption of the cell membrane and the leakage of cytoplasmic contents. The UPLC–MS/MS analysis showed that the contents of gallic acid, (?)–epigallocatechin, (+)–catechin, (?)–epigallocatechin gallate, (?)–epicatechin gallate, aloe–emodin, rhein, emodin, chrysophanol, and physcion, were 5.27%, 3.30%, 1.08%, 19.32%, 5.46%, 0.23%, 0.56%, 1.28%, 0.75% and 0.39% in plant extracts, respectively. Results of feeding experiment showed that feeding crucian carp with 1.0% and 2.0% plant extracts significantly enhanced specific growth rate, serum total protein, lysozyme, catalase and superoxide dismutase activities, and decreased the feed conversion rate, malondialdehyde contents and the mortality rate (P < 0.05). CONCLUSION: It can be concluded that plant extracts added to fish feed can act as natural antimicrobial and immunostimulants to prevent pathogenic infection, enhance immune response, and promote growth of the fish. © 2012 Society of Chemical Industry