微藻中的高附加值天然产物与挖掘策略

微藻是一类单细胞的光合自养真核生物,因为生长速度快,油脂含量高,对土地和水资源的要求宽松而被认为是下一代的液体燃料来源。此外,微藻还能够生产多种多样的天然化合物,包括微藻多糖、长链不饱和脂肪酸、色素和生物碱等。与植物中丰富的生物碱研究相比,对微藻中生物碱的研究仍处于起步阶段。微藻中的许多天然产物,通常具有多样性的生物活性,可以作为食品添加剂、营养保健品乃至医药,具有较高的经济价值。本文将简要介绍微藻产生的几类高附加值产品,并就微藻中高附加值天然产物的挖掘策略与规模化培养做简要的探讨。     

LED光质调控微藻生长及目标产物积累的研究进展

光是影响微藻光自养生长的最重要因素.LED光质在调控微藻生长及目标产物积累方面的巨大优势已经引起了诸多研究者及相关企业的高度重视.基于LED光质调控技术开发的微藻培养工艺有望革新现有生产技术,促进微藻产业的快速发展.为此,本文阐述了微藻可吸收利用的光谱范围及光受体、不同LED光质对微藻生长及目标产物积累的影响、基于LE...     

微藻对污水中重金属的生物吸附(英文)

在我国,水源污染问题异常突出,特别是水体重金属污染情况非常严重,因此,如何有效治理水体重金属污染成为了摆在科技工作者面前十分紧迫的任务。利用微藻生物吸附来治理水体重金属污染是一种经济、简便、有效可行的方法,具有极其广阔的应用前景。论文介绍了我国近年水体污染的状况及水体重金属污染特点;综述了水体重金属污染对水体植物、水体动物以及人类潜在的危害;比较了几种常见治理重金属污染的方法;分析了微藻吸附水体重金属的优点,并阐述了微藻对重金属生物吸附的机理及影响生物吸附过程的外在因素;最后提出了今后的研究发展方向。     

废水培养微藻藻种遴选及其组分积累的研究进展

利用废水培养微藻能够降低微藻的培养成本,同时削减污染.微藻的蛋白质、多糖和油脂等组分是影响其后续资源化利用的重要因素.本文重点综述了以废水为基质培养微藻的研究进展,从组分积累的角度,分析了微藻种类的选择依据,探讨了影响微藻生长的因素和提高产量的方法,并对藻体中组分的合成机制进行了讨论,提出未来废水培养微藻技术面临的挑战...     

微藻规模培养技术研究进展

产油微藻是最具潜力的生物能源油脂资源之一,有关微藻生物能源的技术研究开发近年来受到国内外持续重视。微藻能源生产是一个涉及到从藻种、规模培养技术与装备,到能量转化加工全产业链的复杂过程,其中以解决微藻生物量资源的规模培养是整个产业过程的核心。从微藻的产能潜力分析出发,对微藻的光自养与异养模式以及微藻的开放池和光反应器培养研究进展进行了总结,特别分析了近些年发展起来的微藻序贯式异养—稀释—光诱导和贴壁培养技术等。并对涉及微藻培养的相关技术包括光能利用、水源和二氧化碳源解决,以及污染及其控制研究进展进行了分析。在此基础上,提出微藻规模培养必须以高效抗逆工业性状和高值化学品联产特色藻种的选育,与装备创新为重点和突破口,并将废气/废水等利用与规模培养相结合,从而构建起与环境处理相耦联的微藻能源—高值化学品多联产产业技术体系。     

利用废水培养微藻的研究进展

微藻被认为是一种有潜力的、可被开发为再生能源的重要生物材料。一些微藻种类具有较强的异养和混养能力,能直接利用有机物作为碳源。工农业生产和城市生活中所排放的废水中通常含有大量的有机碳、氮、磷等营养物质。利用废水培养微藻,一方面可以将废水中的碳、氮、磷等营养物质转化为具有更高价值的微藻生物质,另一方面又可实现废水的净化和营养物质的再利用。本综述了不同种类废水的特点,讨论了两类微藻培养模式的优劣,同时还探讨了微藻对营养元素的利用,并总结了微藻培养需突破的瓶颈。     

产生物柴油微藻培养研究进展

石油的大量使用会导致能源枯竭和温室气体（CO2）排放的增加。为了实现经济和环境的和谐发展,必须使用可再生能源代替石油。可再生能源使用后不会造成温室气体排放的增加。生物柴油是一种理想的可再生能源, 能满足以上要求,所以近年来得到迅速发展。微藻是一种主要利用太阳能固定 CO2,生成制备生物柴油所需油脂的藻类。因此以微藻油脂为原料转化成的生物柴油是石油理想的替代品。简要介绍了产油微藻的种类和微藻油脂的合成,较详细地阐述了微藻自养培养、异养培养、生物反应器、工程微藻的最新研究进展,并初步展望了微藻产油研究的未来发展方向。     

微藻降解废水污染物的研究进展

微藻在废水处理方面有着很好的开发潜能和极大的优势,在去除氮、磷、富集重金属和降解有毒有机物质的同时,还能作为食品添加原料和养殖饲料等。重点针对微藻的特点及类型、水处理体系的优缺点、废水中的应用及氮磷的去除、重金属离子的富集和难降解有机物的降解机理进行了介绍,并阐述了微藻处理废水中存在的问题及展望了该领域今后的研究方向。     

藻源污染物特性对高藻水微滤处理过程中膜污染的影响

采用不同生长时期的藻细胞、藻源型有机物(AOM)及原藻液进行过滤实验,研究不同生长时期的藻源污染物对膜污染的影响特性及机制。利用UMFI法分析不同生长时期的藻细胞、AOM及原藻液的污染程度;采用CRITIC分析法定量分析了不同生长时期的AOM和藻细胞在混合过滤过程中对膜污染的贡献率,同时采用混合污染堵塞模型分析了不同生长时期的原藻液不同过滤阶段的主要污染堵塞类型。结果表明, 3个生长时期的藻细胞及AOM的膜污染程度均为对数期最轻;值得注意的是,在原藻液过滤过程中藻细胞及AOM的膜污染贡献率随着生长时期的不同而有所变化,其中AOM的污染权重随着生长时期的延长不断减小,而藻细胞的污染权重随着生长时期的延长不断增大。不同生长时期的原藻液过滤过程中均呈现两段式污染堵塞类型,并且后段均为滤饼堵塞。研究不仅阐明了藻源型污染物特性对微滤处理高藻水膜污染的影响机制,同时也为改善膜污染的技术开发提供参考。     

微藻规模化培养研究进展

微藻作为地球上最古老的物种之一,其诞生可追溯到35亿多年前。微藻的种类十分丰富,形态也多种多样。微藻一般都含有叶绿体,因此可进行光合作用,有研究表明微藻固定CO_2的能力是陆地植物的10倍。微藻以其丰富的代谢产物及独特的生理特性在可再生能源、生物医药、食品工业和环境监测等方面有着广泛的应用。然而如何在控制成本的前提下对微藻进行规模化培养成为困扰微藻应用行业的一大难题。为此,本文将从微藻的生化特点及其在各领域中的应用、微藻的规模化培养和微藻的采收3个方面对微藻的规模化培养近十年的研究进展进行综述,旨在为微藻高效培养、低成本采收的研究开发提供参考。     

Escherichia coli behavior in the presence of organic matter released by algae exposed to water treatment chemicals

When exposed to oxidation, algae release dissolved organic matter with significant carbohydrate (52%) and biodegradable (55 to 74%) fractions. This study examined whether algal organic matter (AOM) added in drinking water can compromise water biological stability by supporting bacterial survival. Escherichia coli (1.3 x 10(5) cells ml(-1)) was inoculated in sterile dechlorinated tap water supplemented with various qualities of organic substrate, such as the organic matter coming from chlorinated algae, ozonated algae, and acetate (model molecule) to add 0.2 +/- 0.1 mg of biodegradable dissolved organic carbon (BDOC) liter(-1). Despite equivalent levels of BDOC, E. coli behavior depended on the source of the added organic matter. The addition of AOM from chlorinated algae led to an E. coli growth equivalent to that in nonsupplemented tap water; the addition of AOM from ozonated algae allowed a 4- to 12-fold increase in E. coli proliferation compared to nonsupplemented tap water. Under our experimental conditions, 0.1 mg of algal BDOC was sufficient to support E. coli growth, whereas the 0.7 mg of BDOC liter(-1) initially present in drinking water and an additional 0.2 mg of BDOC acetate liter(-1) were not sufficient. Better maintenance of E. coli cultivability was also observed when AOM was added; cultivability was even increased after addition of AOM from ozonated algae. AOM, likely to be present in treatment plants during algal blooms, and thus potentially in the treated water may compromise water biological stability.     

Escherichia coli Behavior in the Presence of Organic Matter Released by Algae Exposed to Water Treatment Chemicals

When exposed to oxidation, algae release dissolved organic matter with significant carbohydrate (52%) and biodegradable (55 to 74%) fractions. This study examined whether algal organic matter (AOM) added in drinking water can compromise water biological stability by supporting bacterial survival. Escherichia coli (1.3 × 10⁵ cells ml⁻¹) was inoculated in sterile dechlorinated tap water supplemented with various qualities of organic substrate, such as the organic matter coming from chlorinated algae, ozonated algae, and acetate (model molecule) to add 0.2 ± 0.1 mg of biodegradable dissolved organic carbon (BDOC) liter⁻¹. Despite equivalent levels of BDOC, E. coli behavior depended on the source of the added organic matter. The addition of AOM from chlorinated algae led to an E. coli growth equivalent to that in nonsupplemented tap water; the addition of AOM from ozonated algae allowed a 4- to 12-fold increase in E. coli proliferation compared to nonsupplemented tap water. Under our experimental conditions, 0.1 mg of algal BDOC was sufficient to support E. coli growth, whereas the 0.7 mg of BDOC liter⁻¹ initially present in drinking water and an additional 0.2 mg of BDOC acetate liter⁻¹ were not sufficient. Better maintenance of E. coli cultivability was also observed when AOM was added; cultivability was even increased after addition of AOM from ozonated algae. AOM, likely to be present in treatment plants during algal blooms, and thus potentially in the treated water may compromise water biological stability.     

Harvesting of Scenedesmus obliquus FSP-3 using dispersed ozone flotation

The Scenedesmus obliquus FSP-3, a species with excellent potential for CO₂ capture and lipid production, was harvested using dispersed ozone flotation. While air aeration does not, ozone produces effective solid-liquid separation through flotation. Ozone dose applied for sufficient algal flotation is similar to those used in practical drinking waterworks. The algae removal rate, surface charge, and hydrophobicity of algal cells, and fluorescence characteristics and proteins and polysaccharides contents of algogenic organic matter (AOM) were determined during ozonation. Proteins released from tightly bound AOM are essential to modifying the hydrophobicity of bubble surfaces for easy cell attachment and to forming a top froth layer for collecting floating cells. Humic substances in the suspension scavenge dosed ozone that adversely affects ozone flotation efficiency of algal cells.     

Effect of orange peel essential oil on oxidative stress in AOM animals

The processing parameters of pump speed, inlet air temperature, outlet air temperature and homogenization pressure were evaluated. Encapsulation efficiency is high with a satisfied releasing rate. Then, acute otitis media (AOM) animal model was built and diet containing orange peel essential oil microcapsules were administrated to AOM animals. Pharmacological test showed that orange peel essential oil treatment could decrease serum and cochlea malondialdehyde (MDA), immunoglobulins A (IgA), immunoglobulins G (IgG), immunoglobulins M (IgM) levels and increase antioxidant enzymes activities. It can be concluded that orange peel essential oil treatment could decrease oxidative injury in acute otitis media rats.     

Enrichment of ANME‐2 dominated anaerobic methanotrophy from cold seep sediment in an external ultrafiltration membrane bioreactor

Anaerobic oxidation of methane (AOM) coupled to sulfate reduction is a microbially mediated unique natural phenomenon with an ecological relevance in the global carbon balance and potential application in biotechnology. This study aimed to enrich an AOM performing microbial community with the main focus on anaerobic methanotrophic archaea (ANME) present in sediments from the Ginsburg mud volcano (Gulf of Cadiz), a known site for AOM, in a membrane bioreactor (MBR) for 726 days at 22 (± 3)°C and at ambient pressure. The MBR was equipped with a cylindrical external ultrafiltration membrane, fed a defined medium containing artificial seawater and operated at a cross flow velocity of 0.02 m/min. Sulfide production with simultaneous sulfate reduction was in equimolar ratio between days 480 and 585 of MBR operation, whereas methane consumption was in oscillating trend. At the end of the MBR operation (day 726), the enriched biomass was incubated with ¹³C labeled methane, ¹³C labeled inorganic carbon was produced and the AOM rate based on ¹³C‐inorganic carbon was 1.2 μmol/(g_dw d). Microbial analysis of the enriched biomass at 400 and 726 days of MBR operation showed that ANME‐2 and Desulfosarcina type sulfate reducing bacteria were enriched in the MBR, which formed closely associated aggregates. The major relevance of this study is the enrichment of an AOM consortium in a MBR system which can assist to explore the ecophysiology of ANME and provides an opportunity to explore the potential application of AOM.     

Photophysiology of Surface Phytoplankton Communities in a Transect from the Mouth of the Peene‐Strom to the Arkona Sea (Baltic)

The potential of surface phytoplankton to withstand photostress was investigated in August 1998 along a transect from the mouth of the Peene‐Strom (Pomeranian Bight) to the open Arkona Sea (Baltic). Photosynthetic efficiency, algal class composition and pigment pattern were determined. Algae were photoinhibited by artificial illumination and the kinetics of recovery were recorded. Under photoinhibitory treatment, algae from the estuary showed a low effective quantum yield but a high potential to recover their maximum photosynthetic efficiency. Contrary to this, the relatively high effective quantum yield of open sea algae under photoinhibitory treatment is accompanied by a low final recovery of maximum photosynthetic efficiency. These phenomena are discussed with respect to nutrient supply, algal class composition and to different strategies of algae to react to light stress. Literature data of summer primary productivity of open sea and coastal algae are compared with our data on electron transport rates. This revealed a low influence of photoinhibitory effects on productivity.     

A two-stage ultrafiltration and nanofiltration process for recycling dairy wastewater

A two-stage ultrafiltration and nanofiltration (UF/NF) process for the treatment of model dairy wastewater was investigated to recycle nutrients and water from the wastewater. Ultracel PLGC and NF270 membranes were found to be the most suitable for this purpose. In the first stage, protein and lipid were concentrated by the Ultracel PLGC UF membrane and could be used for algae cultivation to produce biodiesel and biofuel, and the permeate from UF was concentrated by the NF270 membrane in the second stage to obtain lactose in retentate and reusable water in permeate, while the NF retentate could be recycled for anaerobic digestion to produce biogas. With this approach, most of dairy wastewater could be recycled to produce reusable water and substrates for bioenergy production. Compared with the single NF process, this two-stage UF/NF process had a higher efficiency and less membrane fouling.     

Patterns of Anti-Osteoporosis Medication Use among Women at High Risk of Fracture: Findings from the Global Longitudinal Study of Osteoporosis in Women (GLOW)

Objective

To assess patterns of anti-osteoporosis medication (AOM) use over 3 years among women at high risk of major fracture.

Methods

The GLOW registry follows a cohort of more than 40,000 women aged ≥55 from 615 primary care practices in 10 countries. Self-administered surveys (baseline, 12, 24, and 36 months) collected data on patient characteristics, perception of fracture risk, and AOM use. FRAX scores were calculated from the baseline surveys and women classified as high risk if their FRAX 10-year probability of major fracture was ≥20%.

Results

A total of 5774 women were classified as at high risk and had complete data over 3 years. At baseline, 2271 (39%) reported receiving AOM, 739 (13%) reported prior but not current use, and 2764 (48%) said they had never used AOM. Over 3 years, 85% of baseline non-users continued as non-users and 15% initiated AOM; among baseline users, 49% continued the same medication class, 29% stopped AOM, and 12% switched. Women who stopped AOM were less likely to self-report osteoporosis (HR 0.56, 95% CI 0.42–0.75) than women who continued AOM. Compared with non-users who did not begin treatment, women initiating AOM were more likely to report a diagnosis of osteoporosis (HR 11.3, 95% CI 8.2–15.5) or osteopenia (HR 4.1, 95% CI 2.9–5.7) and be very concerned about osteoporosis (HR 1.9, 95% CI 1.3–2.8).

Conclusions

Less than 40% of women at high risk of fracture reported taking AOM. Women who stopped AOM were less likely to believe they have osteoporosis. Women who initiated treatment appeared motivated primarily by a diagnosis of osteoporosis or osteopenia and concern about the condition.     

T cell deficiency leads to liver carcinogenesis in azoxymethane-treated rats

There is an increasing amount of evidence suggesting that T cell deficiency contributes to tumor development. However, it is unclear whether T cell deficiency leads to liver and colon carcinogenesis. The aim of this study was to investigate the role of T cells on liver and colon carcinogenesis. Athymic F344/N Jcl-rnu/- (nu/nu) rats and euthymic F344/N Jcl-rnu/+(nu/+) rats were administered the carcinogen azoxymethane (AOM) at a dose of 15 mg/kg body wt once a week for 2 weeks. At 48 weeks after the second carcinogen treatment, the rats were sacrificed, and livers and colons were examined. Apoptosis and cell proliferation were evaluated by DNA fragmentation and proliferating cell nuclear antigen assays, respectively. Wild-type p53 and members of the Jun and Fos oncogene families were detected by Western blotting. AOM treatment induced 100% liver tumor and 63.6% colon tumor incidence in T cell-deficient nu/nu rats, compared with 0% and 38.5% incidence in nu/+ rats. T cell deficiency promoted the inhibitory action of AOM on apoptosis in both liver and colon at 48 weeks. In contrast, T cell deficiency increased cell proliferation after AOM treatment in both tissues. Wild-type p53 was reduced in both tissues of T cell-deficient rats. AOM treatment induced c-Jun and c-Fos expressions in the liver but increased only Fos B in the colon, whereas T cell deficiency enhanced c-Jun overexpression in the liver. These results suggest that T cell deficiency leads to liver carcinogenesis partly by a reduction in wild-type p53 and increasing c-Jun expression in AOM-treated rats.