沙柳原料高浓度底物酶解发酵乙醇工艺

为了提高沙柳生物转化过程的经济可行性,考察了沙柳原料经过蒸爆、超微粉碎+稀酸、超微粉碎+稀碱预处理后高浓度底物补料酶解的效果,并对其高浓度水解糖液进行了乙醇发酵。结果表明:蒸爆处理法水解效果最好,通过补料酶解,底物质量分数可以达到30%,酶解液中总糖质量浓度达到132 g/L,葡萄糖质量浓度105 g/L;超微粉碎+稀酸预处理原料底物质量分数可以达到22%,酶解液中总糖质量浓度达到123 g/L,葡萄糖质量浓度73 g/L;超微粉碎+稀碱预处理原料底物质量分数可以达到22%,酶解液中总糖质量浓度133 g/L,葡萄糖质量浓度77 g/L。3种预处理使沙柳原料的酶解糖液都可以较好地被酿酒酵母利用发酵产乙醇,蒸爆处理原料的酶解糖液乙醇发酵效果最好,乙醇质量浓度达到47 g/L。     

高温高浓发酵工业啤酒酵母菌种的构建

高温高浓发酵技术作为一项新兴的啤酒生产技术,它为啤酒生产带来诸多利益的同时,也存在着发酵结束后酵母絮凝性下降、高级醇生成量过高等系列问题。为提高高温高浓发酵条件下酿酒酵母的絮凝性同时降低高级醇的合成能力,首先构建了以酿酒酵母BAT2基因为整合位点过表达FLO5基因的菌株,重组菌株S6-BF的絮凝性达到67.67%,比出发菌株S6提高了29%,而高级醇生成量仅降低5.9%;进一步构建以BAT2基因为整合位点再次过表达FLO5基因的菌株,与出发菌株S6相比,重组菌株S6-BF2的絮凝性提高了63%,达到85.44%,高级醇生成量下降至159.58 mg/L,降低了9.0%;通过弱化线粒体支链氨基酸转氨酶(BAT1)的表达,高级醇的生成量得到进一步的降低,达到142.13 mg/L,比原始菌株S6降低了18.4%,同时重组菌株S6-BF2B1的絮凝性没有受到影响;风味物质的测定结果表明啤酒中醇酯比例较为合理。研究结果对工业啤酒酵母发酵后的沉降分离和提高啤酒风味品质有着重要的意义。     

黑胸大蠊浓核症病毒的研究

1990年我们从黑胸大蠊(Periplaneta fuliginosa)的若虫中,首次分离发现黑胸大蠊浓核症病毒(PfDNV)。根据Kock's 法则,将它进行了回感试验,结果表明：这一病毒对该虫可引起同样的病症,并从中重新分离出完全一样的DNV。同时,对诊病毒进行了分类鉴定,结果表明：其病毒粒子的形态结构呈球状二十面体,大小一致, 直径为20 nm; 病毒核酸呈线状, 长度为1.7/μm 分子量为1.7x10⁶ Dal(ssDNA),基因组为单链DNA;结构蛋白为4条多肽,分子量分别为81k、62k、53k、29k。根据病毒分类命名原则,证明从黑胸大蠊中分离出的病毒属细小病毒科(Parvoviridae)中的浓核症病毒属(Desovirus)。我们将它命名为黑胸大蠊浓核症病毒Periplaneta fugtnosa Densonucleosis Virus简称PfDNV).     

工业酵母抗逆机理研究进展

工业酵母利用木质纤维素等生物质资源发酵生产醇、酮、醛、酸等各种化合物,是解决人类面临的不可再生资源和能源危机的重要途径,这激发了人们对木质纤维素水解液为原料和环保节能型浓醪发酵技术的极度关注。然而高浓度底物、产物、渗透压、木质纤维素水解液中抑制性物质、发酵过程温度的提高均会抑制微生物生长代谢及发酵性能,这是发酵行业"瓶颈"问题。本文简述了渗透压、温度及抑制性物质对酵母细胞生长的危害,并从胞内稳态平衡、分子水平等方面着重叙述工业酵母对渗透压、温度及抑制性物质的抗逆机制研究进展。     

固态间歇补料乙醇生料发酵新工艺

浓醪发酵是酒精生产的发展方向。与现行酒精厂普遍采用的热蒸煮工艺相比, 生料发酵技术的发展使得浓醪发酵更容易进行。本研究首次在生料发酵中直接采用固态原料间歇补料, 比较了STARGENTM生淀粉水解酶间歇补料工艺和传统无补料工艺, 并对不同补料方式进行了研究。结果表明: 与传统无补料生料发酵工艺相比, 在相同的干基配料浓度30%、相同的生料酶添加量0.22%(W/W)的条件下, 采用15%的起始配料浓度、发酵15~25 h进行间歇补料的新工艺, 酒精产量从17.06%提高到18.50%。该间歇补料优化工艺的建立, 丰富了生料发酵技术的应用。     

芦苇（Phragmites communis Trin．）生物生产力及其对大气CO＿2加浓的响应

本文对上海浦东东海海滩上［３１°１＇Ｎ］芦苇植被自堤至海水边各地段的生物生产力、生长特性及土壤状况作了测定。其平均生物生产力为２．０７４±０．５５４ｋｇｍ￣（－２）ａ￣（－１）,其中地上部和地下部生物量分别为１．４３３±０．３８２和０．６４１±０．５６６ｋｇｍ￣（－２）ａ￣（－１）。观察了自芦苇出土起,大气ＣＯ＿２浓度加倍对芦苇生长的影响。结果表明,处理４４ｄ后植株叶面积和比叶重相应提高,生物生产力比对照增加５３．７％,其光合产物主要分配在地上部分。试验结束时,ＣＯ＿２加浓处理的叶片叶绿素含量和在正常空气中的光合速率与对照相似。     

家蚕浓核症病毒感染昆虫细胞系的电镜观察

本实验首次用中国株家蚕浓核症病毒感染三株昆虫细胞系:油桐尺蠖卵巢细胞系(BS-484)、甘兰夜蛾卵巢细胞系(NIAS—MB—19)和秋粘虫卵巢细胞系(IPLB—SF—21)。结果仅在BS—484细胞中观察到病毒感染引起的细胞病变效应。电镜观察发现在感染的BS—484中,细胞核明显膨大,其中核仁活性化,数目增多,同时还观察到核仁膨大和分裂现象。感染5—6天,可看到成熟病毒粒子于核内形成。在感染的细胞质中,线粒体肥大且失去脊,粗面内质网变成小泡体,其内积累大量核糖核蛋白体。许多细胞器空泡化或退化,细胞质中出现一些包含退化细胞器的大型自身吞噬体。     

浓维磷糖浆质量评价及质量研究

现阶段浓维磷糖浆的整体质量状况较差，现行质量标准有待完善。基于此，文章根据国家食品药品监督管理局国家药品标准WS-10001-(HD-1215)-2002-2013，对现行标准中的全部检验项目进行考察，建立了多种检测方法来充分分析其质量，还结合试验结果及其存在的问题提出了改进方案。试验结果显示，按照现行质量标准进行检验，20家生产企业的170批次样品中有7批样品不合格，不合格率为4.1%，不合格项目为维生素B1的含量，探索性研究检验的不合格率为38.2%。文章希望通过评价浓维磷糖浆的质量及现存的问题，为该品种国家标准的修订提供参考依据，同时为药品监管提供技术支持。     

Very high gravity wort fermentation by immobilised yeast

Using calcium alginate-entrapped yeast, 24% (w/w) wort was successfully fermented within 8 days. This is half the time needed for fermentation by free yeast. The highest ethanol concentration obtained was 10.5% (v/v). When the original wort gravity was increased, the specific rate of ethanol production remained constant 0.16 g gh^–1 and the viability did not fall bellow 95% of living cells. Protection of cell against osmotic stress by gel matrix was also confirmed by trehalose measurement. The maximum intracellular trehalose content in calcium alginate-entrapped yeast was 3 times lower compared to free yeast at 30% (w/w) wort fermentation.     

Specific Gravity Increase of Caenorhabditis briggsae with Age

The specific gravity of old Caenorhabditis briggsae was shown to be greater than that of young nematodes. The possible explanations for this age-associated change are discussed.     

Variation in wood density determines spatial patterns inAmazonian forest biomass

Uncertainty in biomass estimates is one of the greatest limitations to models of carbon flux in tropical forests. Previous comparisons of field‐based estimates of the aboveground biomass (AGB) of trees greater than 10 cm diameter within Amazonia have been limited by the paucity of data for western Amazon forests, and the use of site‐specific methods to estimate biomass from inventory data. In addition, the role of regional variation in stand‐level wood specific gravity has not previously been considered. Using data from 56 mature forest plots across Amazonia, we consider the relative roles of species composition (wood specific gravity) and forest structure (basal area) in determining variation in AGB. Mean stand‐level wood specific gravity, on a per stem basis, is 15.8% higher in forests in central and eastern, compared with northwestern Amazonia. This pattern is due to the higher diversity and abundance of taxa with high specific gravity values in central and eastern Amazonia, and the greater diversity and abundance of taxa with low specific gravity values in western Amazonia. For two estimates of AGB derived using different allometric equations, basal area explains 51.7% and 63.4%, and stand‐level specific gravity 45.4% and 29.7%, of the total variation in AGB. The variation in specific gravity is important because it determines the regional scale, spatial pattern of AGB. When weighting by specific gravity is included, central and eastern Amazon forests have significantly higher AGB than stands in northwest or southwest Amazonia. The regional‐scale pattern of species composition therefore defines a broad gradient of AGB across Amazonia.     

Creatinine versus specific gravity-adjusted urinary cadmium concentrations

The aim was to assess how urinary creatinine is affected by age, gender, body size and meat intake, and to determine to what extent such factors might affect the creatinine adjustment of urinary cadmium. The study was based on three Swedish studies: (1) 67 non-smoking women aged 20–50 years (24-h urine samples); (2) 289 men and 434 women aged 16–81 years (spot urine samples); and (3) 98 men and 105 women aged 19–72 years (spot urine samples). The effects of age, body surface area (as an indicator of muscle mass), and meat intake on urinary creatinine and cadmium were analysed using multiple regression analyses. Gender- and age-related variations in urinary creatinine and cadmium adjusted for creatinine or specific gravity were compared by ANOVA or ANCOVA. In the multiple regression analyses, body surface area, gender, age and meat intake were the major determinants of urinary creatinine. Urinary cadmium adjusted for creatinine and specific gravity were also dependent on body size, gender and age. Urinary cadmium adjusted for creatinine was 15–92% higher in women or older individuals than in men or younger individuals. Women or older individuals had –3 to 79% higher urinary cadmium adjusted for specific gravity than men or younger individuals had, and such a difference between gender or age group was less obvious in specific gravity adjustment than in creatinine adjustment. Thus, urinary cadmium adjusted for creatinine is more affected by age, gender, body size and meat intake than is specific gravity adjustment. When comparing individuals or populations with large differences in muscle mass or meat intake, such effects can be especially important. In such studies, specific gravity adjustment seems to be more appropriate.     

Creatinine versus specific gravity-adjusted urinary cadmium concentrations

The aim was to assess how urinary creatinine is affected by age, gender, body size and meat intake, and to determine to what extent such factors might affect the creatinine adjustment of urinary cadmium. The study was based on three Swedish studies: (1) 67 non-smoking women aged 20-50 years (24-h urine samples); (2) 289 men and 434 women aged 16-81 years (spot urine samples); and (3) 98 men and 105 women aged 19-72 years (spot urine samples). The effects of age, body surface area (as an indicator of muscle mass), and meat intake on urinary creatinine and cadmium were analysed using multiple regression analyses. Gender- and age-related variations in urinary creatinine and cadmium adjusted for creatinine or specific gravity were compared by ANOVA or ANCOVA. In the multiple regression analyses, body surface area, gender, age and meat intake were the major determinants of urinary creatinine. Urinary cadmium adjusted for creatinine and specific gravity were also dependent on body size, gender and age. Urinary cadmium adjusted for creatinine was 15-92% higher in women or older individuals than in men or younger individuals. Women or older individuals had -3 to 79% higher urinary cadmium adjusted for specific gravity than men or younger individuals had, and such a difference between gender or age group was less obvious in specific gravity adjustment than in creatinine adjustment. Thus, urinary cadmium adjusted for creatinine is more affected by age, gender, body size and meat intake than is specific gravity adjustment. When comparing individuals or populations with large differences in muscle mass or meat intake, such effects can be especially important. In such studies, specific gravity adjustment seems to be more appropriate.     

Specific gravity and creatinine as corrections for variation in urine concentration in humans,gorillas, and woolly monkeys

Hormones excreted in the urine are widely used to assess the physiological and psychological condition of unrestrained animals. In order to control for variation in the water concentration of urine samples, the hormone concentration is often indexed to the concentration of creatinine. Because there are several problems with using creatinine, we have investigated the efficacy of specific gravity as an alternative basis for adjusting the hormone concentration in humans, gorillas, and woolly monkeys. In an experimental manipulation of human urine hydration, ten volunteers drank a water load proportional to body weight, and provided complete urine collection and saliva samples for four consecutive 20 min intervals. From the urine, we measured cortisol (radioimmunoassay), creatinine (colorimetric assay), and specific gravity (refractometer). Only cortisol was assayed from saliva. During 80 min following water ingestion, cortisol, creatinine, and specific gravity declined as urine became diluted; however, total cortisol excretion remained constant. Only cortisol concentration indexed to specific gravity accurately reflected the consistent cortisol excretion. Specific gravity and creatinine‐corrected cortisol values were highly correlated but were significantly different. Salivary cortisol provided evidence for the relative stability of serum cortisol. To determine the utility of these corrections in other primates, we compared specific gravity‐ and creatinine‐corrected cortisol in urine samples from captive gorillas (N=16) and woolly monkeys (N=8). As with the human study, the two corrections were strongly correlated in each species, but the means were different. Specific gravity correction was superior in revealing the circadian variation in cortisol. Am. J. Primatol. 72:1082–1091, 2010. © 2010 Wiley‐Liss, Inc.     

Improvement of the ethanol productivity in a high gravity brewing at pilot plant scale

A 2³ full factorial design was used to study the influence of different experimental variables, namely wort gravity, fermentation temperature and nutrient supplementation, on ethanol productivity from high gravity wort fermentation by Saccharomyces cerevisiae (lager strain), under pilot plant conditions. The highest ethanol productivity (0.69 g l^–1 h^–1) was obtained at 20°P [°P is the weight of extract (sugar) equivalent to the weight of sucrose in a 100 g solution at 20°C], 15°C, with the addition of 0.8% (w/v) yeast extract, 24 mg l^–1 ergosterol and 0.24% (v/v) Tween 80.     

A comparative study on physiological activities of lager and ale brewing yeasts under different gravity conditions

High gravity (HG) or very high gravity (VHG) brewing has become popular in modern breweries due to its economic and product quality advantages. However, there are the negative impacts such as the fermentation performance of brewer??s yeast in HG or VHG wort, which are closely related to changes in cell physiological activity. In the present study, 3 kinds of worts, with different gravities, were used to examine the systematic effects on fermentation performance and physiological activity of lager yeast FBY009505 (Saccharomyces pastorianus) and ale yeast FBY0099 (Saccharomyces cerevisiae), as well as the resulting beer flavor. Results showed that the responses of FBY009505 and FBY0099 to the HG or VHG worts were similar. The specific fermentation rate and viability of cropped yeast of FBY009505 and FBY0099 were decreased with increasing wort gravity. The increased wort gravity resulted in the increase of energy charge and the decrease of ??-glucosides transport rate and glycolytic enzyme activities. Moreover, the environmental stresses in the HG or VHG wort showed a higher inhibitory activity against ??-glucoside transport than glycolytic enzymes. The content of intracellular trehalose and glycerol of FBY009505 and FBY0099 increased with the increase in wort gravity. The results from this study provided a potential means to systematically understand the physiology of brewer??s yeast under HG or VHG conditions.     

Specific gravity as an alternative to creatinine for estimating urine concentration in captive and wild chimpanzee (Pan troglodytes) Samples

The measurement of hormones in urine has become a widely used technique in primatology. Because urine concentration varies according to fluid intake, concentration must be measured in each sample collected, and hormone values are always expressed per unit of concentration. Traditionally, creatinine has been used as a concentration index, but some studies in humans have shown that creatinine varies among populations and even within and between individuals within a population, and that it begins to degrade after just one freeze-thaw cycle. In addition, creatinine measurement is relatively time-consuming and expensive and creates hazardous waste. In this study, we tested the hypothesis that specific gravity, or the ratio of the density of a sample to that of water, is highly correlated with creatinine measurement in urine samples collected from captive chimpanzees at the New Iberia Research Center in Louisiana and wild chimpanzees at the Ngogo study site in the Kibale National Park, Uganda. We found that specific gravity and creatinine were highly correlated in both captive (N=124) and wild (N=13) chimpanzee samples, and that specific gravity measurement was robust to actual and simulated transport conditions and repeated freeze-thaw cycles. We recommend that researchers consider specific gravity measurement as a preferable alternative to creatinine measurement in their studies of primate endocrinology.     

Does canopy position affect wood specific gravity in temperate forest trees?

The radial increases in wood specific gravity known in many tree species have been interpreted as providing mechanical support in response to the stresses associated with wind loading. This interpretation leads to the hypothesis that individuals reaching the canopy should (1) be more likely to have radial increases in specific gravity and (2) exhibit greater increases than individuals in the subcanopy. Wood specific gravity was determined for three species of forest trees (Acer rubrum, Fagus grandifolia and Tsuga canadensis) growing in central Massachusetts, USA. Acer rubrum shows radial increases in specific gravity, but these increases are not more pronounced in canopy trees; the other two species show a pattern of radial decreases. The degree of radial increase or decrease is influenced by tree height and diameter. Of the dominant tree species for which we have data, A. rubrum, Betula papyrifera and Pinus strobus show radial increases in specific gravity, whereas F. grandifolia, T. canadensis and Quercus rubra show decreases. The occurrence of radial increases in B. papyrifera and P. strobus, which are often canopy emergents, suggests that it is overall adaptive strategy that is important rather than position (canopy vs. subcanopy) of any individual tree. It is suggested that radial increases in specific gravity are associated with early-successional status or characteristics and decreases with late-successional status or persistence in mature forest.