酿酒酵母工程菌产青蒿酸的发酵动力学研究

以青蒿酸产量为考察指标，在50 L发酵罐中对酿酒酵母（Saccharomyces cerevisiae）工程菌1211发酵产青蒿酸的溶氧参数进行优化。在此基础上，根据Logistic方程及Luedeking-Piret方程构建酿酒酵母工程菌1211分批发酵产青蒿酸的动力学模型。结果表明，当溶氧参数为25%～30%时，青蒿酸产量最高，为（6 269.6±100.3）mg/L。青蒿酸合成与菌体生长呈现部分生长偶联型。通过Origin 9.0软件对动力学模型进行非线性拟合，发现S. cerevisiae工程菌1211的菌体繁殖生长、青蒿酸合成以及基质消耗动力学模型的拟合度R2分别达到了0.995 85、0.979 04和0.995 48，该动力学模型能够很好的描述S. cerevisiae工程菌1211分批发酵过程。该研究为青蒿酸的低成本发酵及工业化大规模发酵生产提供了理论基础。     

细菌纤维素生产菌株的动力学研究

对细菌纤维素生产菌株QAX993的发酵动力学特性进行了研究，基于Logistic方程，提出了细胞生长动力学、基质消耗动力学、纤维素生成动力学模型，得到了描述静态分批发酵过程的动力学模型及模型参数，同时对实验数据与模型进行了验证，模型计算值与实验数据拟合良好，模型基本上反映了该菌株分批发酵过程的动力学特征。     

绞股蓝皂苷发酵动力学研究

对酵母菌转化绞股蓝皂苷的发酵动力学进行了研究。应用Logistic方程和Luedeking-Piret方程,得到了描述酵母菌体生长、产物形成和底物消耗的动力学模型,并对各动力学模型进行了验证,表明所建模型相关性较好,能够很好地描述该菌株转化绞股蓝皂苷的动力学特征。这将为今后进一步研究和预测酵母转化过程奠定了一定的理论基础。     

具有时滞和分段常数变量的食物有限模型的稳定性与分支分析(英文)

讨论了具有时滞和分段常数变量的食物有限模型的局部稳定性以及翻转分支和Neimark-Sacker分支.利用分段常数理论、中心流行定理以及分支理论得到翻转分支和Neimark-Sacker分支稳定的充分条件.通过举例和数值模拟验证了所得结论的正确性与可行性,并充分体现了该单种群生物系统复杂的动力学行为.     

Lipstatin生产菌株发酵动力学研究

对Lipstatin生产菌株--毒三素链霉菌发酵动力学特性进行了研究,提出了细胞生长动力学、基质消耗动力学、产物生成动力学模型,得到了描述该发酵过程的菌体生长动力学方程、基质消耗动力学方程、产物生成动力学方程.采用Origin软件,对实验数据与模型进行了拟合,拟合度良好,三个模型的线性相关性R值均在0.988以上.     

新疆药桑葚酵素发酵动力学模型及其发酵比速率的研究

为了进一步研究新疆药桑葚酵素发酵过程中发酵动力学变化情况,针对发酵过程中乳酸菌生长、总酸生成及还原糖基质消耗情况,该研究应用Logistic模型、SGompertz模型、DoseResp模型和Boltzmann模型进行非线性拟合,并依据相关系数判断其可靠性。结果表明,在乳酸菌生长动力学模型中Logistic模型的拟合效果最佳,其相关系数最接近1。在还原糖基质消耗动力学模型中DoseResp模型和Boltzmann模型均可用于定量描述和预测药桑葚酵素发酵过程中还原糖基质消耗情况。在总酸生成动力学模型中Logistic模型的拟合效果最佳。所选模型拟合发酵过程均为可行,为药桑葚酵素发酵进一步工业化生产和扩大市场提供了理论基础。     

木醋杆菌在转盘式反应器中的发酵动力学研究

对细菌纤维素生产菌株QAX993的发酵动力学特性进行了研究,基于Logistic方程,提出了菌体生长动力学、基质消耗动力学、纤维素合成动力学模型,得到了使用转盘式反应器分批发酵合成细菌纤维素的动力学模型参数,同时对实验数据与模型进行了比较,模型与实验数据能够较好地拟合,模型基本上反映了该菌株在转盘式反应器中分批发酵过程的动力学特征.     

酱醪生香酵母的选育及其生长动力学研究

该研究从酱醪中筛选耐盐生香酵母，结合形态学观察、生理生化试验及分子生物学技术对其进行鉴定及耐盐性分析，采用单因素试验及响应面试验对其培养条件进行优化，并对其生长动力学进行研究。结果表明，筛选获得一株耐盐生香酵母(编号为Flae04)，经鉴定为鲁氏接合酵母(Zygosaccharomyces rouxii)，该菌株可耐受20%的盐浓度；其最适培养条件为接种量1%，初始pH值5.7，培养温度28℃，培养时间48 h，转速181 r/min。在此优化条件下，酵母Flae04的细胞数为3.33×10⁸ CFU/mL；基于Logistic方程与类LuedekingPiret方程分别建立细胞生长动力学模型和底物消耗动力学模型，相关系数R2分别为0.997和0.995，说明试验值与模型拟合良好，表明所建模型能较好的反映该酵母分批培养的生长规律。     

玉米秸秆水解液发酵产生物油脂动力学研究

对发酵性丝孢酵母在玉米秸秆水解液中发酵合成微生物油脂动力学特性进行了研究.采用Logistic菌体生长模型、Luedeking-Piret模型和产物生成的基质消耗模型,描述了完整发酵过程的动力学特性,提出了发酵过程中菌体生长、微生物油脂合成、基质消耗的动力学模型.采用牛顿迭代法对模型参数进行非线性拟合,结果表明,模型计算与试验数据能较好地拟合,菌体生长、产物油脂生成及糖分消耗等3条曲线的相关指数R2分别为0.990、0.987和0.890.表明该动力学模型可以较好描述发酵性丝孢酵母发酵过程的动力学特征.     

一类非均匀恒化器食物网的共存态

讨论一类带有Beddington-DeAngelis型功能反应函数的非均匀恒化器食物网模型的共存态;该模型除了营养物以外,还包含2个捕食者种群和一个食饵种群.应用Dancer不动点指数和度理论的知识,给出了该系统共存态的充分和必要条件.     

脆弱性理论视角下传统生鲜食品市场公共卫生风险及其治理

随着我国城市治理中风险因素的增加,传统生鲜食品市场已成为我国大型城市治理中的脆弱环节。为避免暴发由传统生鲜食品引发的公共卫生危机,有必要对我国传统生鲜食品市场内蕴藏的公共卫生风险进行分析与评估,进而提升我国公共卫生风险治理的能力。本文以脆弱性理论为研究视角,分析传统生鲜食品市场存在的公共卫生风险,论述我国传统生鲜食品市场在自然、社会、管理以及技术系统等方面的薄弱环节。在此基础上,本文对我国传统生鲜食品市场在脆弱性系统环境下存在的潜在、次生风险提出了有针对性的治理对策。     

Application of molecular methods to demonstrate species and strain evolution of acetic acid bacteria population during wine production

The growth of acetic acid bacteria on grapes or throughout the winemaking process influences the quality of wine, mainly because it increases the volatile acidity. The objective of this study was to analyse how the acetic acid bacteria population evolves in the changing environment of the grape surface and during wine fermentation. We have analysed the influence of yeast inoculation and SO2 addition on acetic acid bacteria populations. These bacteria were analysed at both the species and the strain level by molecular methods such as Restriction Fragment Length Polimorfism (RFLP) of amplified 16S rDNA, and amplification by polymerase chain reaction of Enterobacterial Repetitive Intergenic Consensus (ERIC-PCR) and Repetitive Extragenic Palindromic (REP-PCR). Our results show that the increases in population size are normally accompanied by a proliferation of Acetobacter aceti, which is the main species during fermentation. The diversity of strains is considerable in natural environments such as the grape surface. Changes in the environment during alcoholic fermentation substantially reduce the survival and the diversity of acetic acid bacteria. Few strains are able to survive these conditions and they seem to originate from both the grapes and the winery. To the best of our knowledge this is the first time that acetic acid bacteria are analysed at the strain level in grape surfaces and during winemaking.     

提高食品中益生菌数量的两大新技术

益生菌是一种对人类健康起着重要作用的微生物,并广泛应用于食品生产,然而,益生菌自身比较脆弱,容易受周围环境的影响而导致食品中益生菌菌数的快速下降,严重影响了益生菌的益生作用,因此,对益生菌进行包埋,提高食品中益生菌的稳定性和存活能力将对我们进一步开发益生菌系列产品至关重要.本文根据目前国内外益生菌包埋技术研究的现状,对目前研究较多的微胶囊包埋技术和双层包埋技术的原理,优缺点以及实际应用情况进行综述。     

Isoprenoid quinones as biomarkers of microbial populations in the environment

Isoprenoid quinones are lipid molecules present in all species of respiratory and photosynthetic microorganisms and exhibit marked structural variations depending upon the microbial taxon. Taking advantage of this, quinones have been used not only as chemotaxonomic markers in microbial systematics but also as good measures of microbial populations in the environment in terms of quantity, quality, and activity. Basically, this biomarker approach, called the quinone profile method, is applicable to all environmental samples from which an absolute amount of microbial biomass > or =10(9) cells can be collected. The quinone profile method allows good measurement of both fundamental and applied aspects of ecological and environmental microbiology. In particular, numerical cluster analyses of quinone profiles are useful for monitoring microbial population shifts in an ecosystem which is not amenable to conventional culture methods and molecular techniques. The combined use of molecular techniques and the quinone profile method in this research area should provide more accurate and reliable data regarding population dynamics and community structures.     

密度与施肥对香料烟成熟烟叶中几种酶活性及脯氨酸、丙二醛的影响初探

通过改变香料烟田间群体结构和施肥水平得出：NR、POD活性及丙二醛含量随密度的减小和施氮量的增加而增大；密度和施肥量的互作影响导致各处理间PPO活性差异不显著；密度和施肥对NR和POD活性影响近似，而施肥量对脯氨酸含量的影响大于密度；证实了前人在其它作物和烟类的研究结果即丙二醛含量和脯氨酸含量的变化规律相反，也符合这方面的理论依据。     

Wild mushroom consumption by pickers in the south of Spain: a probabilistic approach

A survey has been made of 300 habitual consumers of the eight species of wild mushrooms most often consumed in the south of Spain. The eight species selected constitute over 95% of the intake of this food in the samples studied. The mean consumption per capita of mushrooms in Spain is of 10.4 kg/year, 8.6 kg of which are consumed during the season, which lasts from between 1 and 3 months. Male pickers from the Huelva province were those who presented the largest intake, their age group being highly influenced by the species. The consumption of each mushroom studied and the total intake were adjusted/fitted to exponential distributions. These distributions could be an effective tool for toxicological or nutritional studies since they permit the evaluation of exposure that makes it possible to calculate the probabilistic risk analysis and the contribution to the reference dietary intake, respectively, for this population group.     

一类非自治食物链模型的局部分歧

研究了一类具Beddington-DeAngelis(B-D)反应函数非自治的食物链模型.以确定时变环境的参数b为分歧参数.用单特征值分歧理论得到了周期解存在的条件,并运用Crandall-Rabinowitz定理证明了单种群分歧解的稳定性.     

Pulsed electric energy and ultrasonication assisted green solvent extraction of bio-molecules from different microalgal species

The effects of physical treatments (pulsed electrical fields (PEF), high voltage electrical discharges (HVED) and ultrasonication (US)) on aqueous extraction of carbohydrates and proteins, and ethanolic extraction of chlorophyll a from three microalgal species (Nannochloropsis sp., P. tricornutum and P. kessleri) have been studied. The total energy consumption of 530 kJ/kg suspension was applied for each treatment. For studied species, HVED was the most effective for extraction of carbohydrates, while US was the most effective for extraction of proteins and chlorophyll a. The observed differences for studied species can reflect the more fragile cell wall structure for P. tricornutum as compared with Nannochloropsis sp. or P. kessleri. The applied PEF, HVED and US treatments along with combinations of aqueous extraction of carbohydrates and proteins, and ethanolic extraction of pigments can be used in future implementations of selective extraction of valuable bio-molecules from microalgae.     

基于AHP法的造纸企业盟友选择与评价

采用对数最小二乘法对AHP法中的判断矩阵进行计算，有效地确定了决策矢量。结合具体实例，在Matlab环境下对AHP法在造纸企业盟友的选择和评价方面展开了应用研究。     

Isolation and characterization of Schizosaccharomyces pombe fragile mutants

Three Schizosaccharomyces pombe fragile mutants requiring the presence of an osmotic stabilizer to grow, that lyse when transferred into hypotonic solutions and that secrete to the extracellular medium more protein than the parental strain were isolated. In the three mutants, the fragile phenotype segregated in a Mendelian fashion, indicating a single chromosomal gene mutation, and behaved as a recessive character. By complementation analysis, the three fragile mutants fell in a single complementation group, defining the same gene (SRB1). Mutations of this gene are responsible for alterations in the cells such as fragile character, increase in the cell wall porosity, changes in the cell morphology and floc-forming ability. The study of the three srb1 alleles indicated that the degree of these alterations is proportional to a significant decrease in the galactomannan fraction of the mutants cell wall. The data presented in this report suggest that the product of the SRB1 gene is critical for the maintenance of the integrity and structure of Sz. pombe cell wall.