高产柠檬酸突变菌株以玉米粉为原料的生物反应器扩大生产研究(英文)

研究目的:研究高产黑曲霉突变菌株以玉米粉为原料的生物反应器扩大发酵,以期获得适合于工业化生产柠檬酸的发酵工艺。创新要点:以玉米粉为原料,系统地研究了筛选得到的高产菌株在50 L生物反应器中不同糖浓度发酵生产柠檬酸的特性,最终优化出适合于工业化生产柠檬酸的发酵工艺。研究方法:(1)利用淀粉酶对粉碎后的玉米进行液化,然后过滤,最终得上清液;(2)以50 L生物反应器作为发酵设备,对筛选得到的高产柠檬酸菌株进行扩大培养;(3)通过测定不同培养时期中积累的柠檬酸含量和剩余的残总糖,最终优化出高效率生产柠檬酸的发酵工艺。重要结论:以不同糖浓度的液化玉米粉上清液作为碳源,突变菌株H4002能积累177.7~196.0 g/L的柠檬酸,效率能达到2.96~3.27 g/(L·h),尤其当糖浓度为210 g/L,H4002菌株表现出最佳的柠檬酸生产水平,如柠檬酸积累187.5 g/L,生产效率达3.13 g/(L·h)。上述结果说明了突变菌株H4002拥有快速生产柠檬酸的能力。     

产柠檬酸黑曲霉高产菌株的筛选

以从湖南科技学院周围菜园土壤中分离得到的黑曲霉作为出发菌株,并初步对其进行了形态鉴定。利用透明圈法进行初步筛选,以产酸能力的强弱作为复筛指标,筛选到了一株高产柠檬酸的优势菌株。在复筛的过程中,采用单因子试验和正交试验对黑曲霉的培养基的成分和浓度进行确定。     

柠檬酸对蛋鸡生产性能影响的研究

试验以基础日粮为对照,在基础日粮中分别添加0.15%、0.25%、0.35%、0.45%、0.55%的柠檬酸,试验期60天,探讨其对蛋鸡生产性能的影响.试验结果表明:各试验组较对照组,产蛋率均有所提高,其中以2、3、5组成绩最佳,显著高于对照组(P<0.05);各试验组的饲料效率均显著高于对照组,其中2、3两组差异极显著(P<0.01);而饲料成本显著低于对照组(P<0.05).日粮中添加柠檬酸对蛋重和蛋形指数无明显影响,但各试验组破壳率都有所下降,蛋壳厚度增加0.02~0.03毫米,高于对照组(P<0.05).     

绿色食品原料标准化生产基地建设探析——以延津县为例

绿色食品事业已成为实施农业品牌化战略、确保农产品质量安全的重要抓手。绿色食品原料生产是绿色食品生产诸多环节的首要环节,要高度重视绿色食品原料标准化基地建设,加强绿色食品原料的优质安全供应。延津县建立以"政府主导、标准规范、产销结合和产业化经营、科技支撑"的基地建设模式,实现了农民增收、企业增效,有力地推动了现代农业的发展。     

以棕榈酸化油为原料微波法制备生物柴油的研究

研究了在微波辐射下,棕榈酸化油在催化剂作用下和甲醇反应制备生物柴油的过程。实验结果表明：该反应最适宜的操作条件为微波输出功率160w,微波反应时间110min,醇油物质的量比7：1,催化剂用量2．50g（相对于100g的棕榈酸化油）,在此条件下反应转化率达到98．78％。与传统的水浴加热相比,采用微波辐射加热制备生物柴油的反应速率快、耗能少、转化率高。     

以《安德烈的晚上》为例谈“突变”在铁凝中短篇小说中的叙事意义

＂突变＂是铁凝中短篇小说创作中较为常用的叙事策略,铁凝善于抓住关键的叙事点,将突如其来的变化适时嵌入叙事过程,形成更为多义的开放式结局和极具穿透力的审美效果。本文以《安德烈的晚上》为例,对此进行分析,并尝试概括＂突变＂的叙事意义。     

以客户需求为导向的生产管理模式——精益生产管理

精益生产管理,是一种以客户需求为导向,以消灭浪费和不断改善为核心,使企业以最少的投入获取成本和运作利润显著提高的一种全新的生产管理模式.以科学合理的制造体系来组织为客户带来增值的生产活动,可以缩短生产周期,从而显著提高企业适应市场万变的能力.     

基于突变级数法的南方红壤侵蚀小流域的生态恢复评价——以朱溪小流域为例

近年来,国内外生态恢复研究多数并未考虑生态系统恢复所具有的突变性.本研究针对生态恢复演变过程的突变特征建立了生态恢复评价指标体系,在ENVI4.2、Arc GIS9.2、MATLAB7.0等3S技术平台上,采用突变级数法对长汀县朱溪小流域生态恢复进行了定量评估和动态趋势分析.研究结果表明：（1）长汀朱溪小流域生态恢复总体较好,80%的流失区都可恢复到Ⅲ级以上（含Ⅲ级）,采取的有效治理措施主要为封禁;（2）对长汀朱溪小流域生态恢复因素主要有植被盖度、水土流失指数、土壤肥力和地表温度,其各个影响因素重要性大小排序为：植被盖度〉水土流失指数〉土壤肥力指数〉地表温度;（3）突变级数法和生态恢复的交叉融合具有重要应用价值和实践意义.研究认为,采用了突变级数法进行综合评价不仅避免了人为制定权重的主观性,也反映了南方红壤侵蚀小流域生态恢复演变过程的突变特征,更为科学地揭示了生态系统恢复变化过程的本质规律.     

高校后勤安全生产标准化管理体系建设研究 ——以西安建筑科技大学为例

习近平总体国家安全观的提出体现了国家对安全生产工作的高度重视,同时法律法规对各行业安全生产工作给与了法律支持.在全国抗击新冠肺炎疫情期间,高校各项教学科研活动的顺利开展对安全生产提出了更高的要求.针对高校安全生产领域因体制机制不健全等原因造成事故的情况,本文以企业安全生产标准化规范为指导,结合西安建筑科技大学实际,分别...     

文化产业网络交易市场生产主体建设的研究--以宿迁市为例

文化产业网络交易市场的推进和发展,在很大程度上,取决于文化产业生产主体队伍的建设。市场、供求、工资、竞争等要素对生产主体的影响并不是孤立的,他们互为因果,相互制约的内在联系和制约作用构成了文化产业交易市场生产主体建设的主要内容。宿迁建设文化产业网络交易市场生产主体,要高起点、科学规划,准确定位,发展区域文化产业网络交易市场,要结合文化资源优势、行业优势和科技创新优势,理顺体制,激发文化生产人才的创造活力,积极培育文化生产龙头企业。     

黑曲霉糖化酶分离纯化与酶学性质研究

纯化了黑曲霉Aspergillus niger FJL0801糖化酶,并对其酶学性质进行研究.粗酶液经纯化后,较粗酶液纯化了38.42倍,酶活回收率达到17.45%.酶最适作用温度为60℃;最适反应pH值为4.5;在60℃下,保温2 h后,相对酶活42%±2.8%.在pH4.5,60℃下,作用时间在60 min以内,其酶活保存89%±2.56%;其酶学性质符合淀粉糖化工业化过程中对酶的要求,该酶比较适合应用于淀粉糖化工业.     

Improvement of xylanase production by Aspergillus niger XY-1 using response surface methodology for optimizing the medium composition

Objective: To study the optimal medium composition for xylanase production by Aspergillus niger XY-1 in solid-state fermentation (SSF). Methods: Statistical methodology including the Plackett-Burman design (PBD) and the central composite design (CCD) was employed to investigate the individual crucial component of the medium that significantly affected the enzyme yield. Results: Firstly, NaNO3, yeast extract, urea, Na2CO3, MgSO4, peptone and (NH4)2SO4 were screened as the significant factors positively affecting the xylanase production by PBD. Secondly, by valuating the nitrogen sources effect, urea was proved to be the most effective and economic nitrogen source for xylanase production and used for further optimization.Finally, the CCD and response surface methodology (RSM) were applied to determine the optimal concentration of each sig-nificant variable, which included urea, Na2CO3 and MgSO4. Subsequently a second-order polynomial was determined by mul-tiple regression analysis. The optimum values of the critical components for maximum xylanase production were obtained as follows: x1 (urea)=0.163 (41.63 g/L), x2 (Na2CO3)=-1.68 (2.64 g/L), x3 (MGSO4)=1.338 (10.68 g/L) and the predicted xylanase value was 14374.6 U/g dry substrate. Using the optimized condition, xylanase production by Aspergillus niger XY-1 after 48 h fermentation reached 14637 U/g dry substrate with wheat bran in the shake flask. Conclusion: By using PBD and CCD, we obtained the optimal composition for xylanase production by Aspergillus niger XY-1 in SSF, and the results of no additional expensive medium and shortened fermentation time for higher xylanase production show the potential for industrial utilization.     

A new mutation （1062 del 16） of iduronate-2-sulfatase gene from a Chinese patient with Hunter syndrome

Objective: To identify the mutations of iduronate-2-sulfatase (IDS) gene, to reveal its mutation features, and to establish a basis for genetic counseling and prenatal gene diagnosis of Hunter syndrome. Methods: Urine glycosaminoglycans (GAGs) assay, PCR and DNA sequencing were performed to detect mutation of IDS gene of the patient and his parents. Results: The result showed that the patient was: DS( ), HS( ), KS(-), CS(-), and that both of his parents were negative. A frame-shift deletion mutation (1062 del 16) was identified in exon 7 of the patient's IDS gene. His parents' genotypes were normal. Conclusion:The patient's mutation was not inherited by his parents but a novel one. The mutation probably altered the primary structure and tertiary structure of IDS enzyme protein remarkably and lowered the activity of IDS enzyme greatly. Therefore it is supposed to be the direct cause of the disorder.     

Novel mutation c.980_983delATTA compound with c.986C>A mutation of the FRMD7 gene in a Chinese family with X-linked idiopathic congenital nystagmus

Objective

To screen mutations in FERM domain-containing protein 7 (FRMD7) gene in two Chinese families with X-linked idiopathic congenital nystagmus (XLICN).

Methods

Common ophthalmic data and peripheral blood of two Chinese XLICN families (families A and B) were collected after informed consent. Genomic DNA was prepared from the peripheral blood of members of the two families and from 100 normal controls. Mutations in the FRMD7 gene were determined by directly sequencing polymerase chain reaction (PCR) products.

Results

We identified a novel mutation c.980_983delATTA compound with c.986C>A mutation in the 11th exon of FRMD7 in family B, and a previously reported splicing mutation c.782G>C (p.R261G) in family A. The mutations were detected in patients and female carriers, while they were absent in other relatives or in the 100 normal controls.

Conclusions

Our results expand the spectrum of FRMD7 mutations in association with XLICN, and further confirm that the mutations of FRMD7 are the underlying molecular mechanism for XLICN.     

Development of a prediction model for child maltreatment recurrence in Japan: A historical cohort study using data from a Child Guidance Center

To develop a prediction model for the first recurrence of child maltreatment within the first year after the initial report, we carried out a historical cohort study using administrative data from 716 incident cases of child maltreatment (physical abuse, psychological abuse, or neglect) not receiving support services, reported between April 1, 1996 through March 31, 2011 to Shiga Central Child Guidance Center, Japan. In total, 23 items related to characteristics of the child, the maltreatment, the offender, household, and other related factors were selected as predictive variables and analyzed by multivariate logistic regression model for association with first recurrence of maltreatment. According to the stepwise selection procedure six factors were identified that include 9–13 year age of child (AOR = 3.43/95%CI = 1.52−7.72), <40 year age of the offender (AOR = 1.65/95%CI = 1.09−2.51), offender’s history of maltreatment during childhood (AOR = 2.56/95%CI = 1.31−4.99), household financial instability or poverty (AOR = 1.64/95%CI = 1.10−2.45), absence of someone in the community who could watch over the child (AOR = 1.68/95%CI = 1.16−2.44), and the organization as the referral source (AOR = 2.21/95%CI = 1.24−3.93). Using these six predictors, we generated a linear prediction model with a sensitivity and specificity of 45.2% and 82.4%, respectively. The model may be useful to assess the risk of further maltreatment and help the child and family welfare administrations to develop preventive strategies for recurrence.     

高中英语写作技能培养模式研究

高中英语写作技能的培养若只重写作结果或过程,或两者兼顾,都很难收到比较理想的效果.以篇章语言学的主述位、主位推进与扩展、句际与段际关系类型、衔接与连贯等理论为基础建立起来的"解读--讨论--模仿--构建"综合教学模式,注重感知、认识、学习、模仿和掌握篇章结构的宏观和微观层面的知识体系,如信息结构、主题思想、主位的推进与扩展、细节的逻辑安排、句际间的衔接、意思的连贯、结构的层次安排等,在此基础上再建构语篇、培养写作技能,效果可能会要好一些.