Research progress in removal of trace carbon dioxide from closed spaces

In this paper, the removal of trace carbon dioxide from closed spaces through membrane process and biotransformation are introduced in detail. These methods include the microalgae photobioreactor, membrane microalgae photobioreactor, supported liquid membrane, membrane gas-liquid contactor, hydrogel membrane, and enzyme membrane bioreactor. The advantages and disadvantages of these methods are compared. It is found that higher CO₂ removal efficiency can be obtained in biotransformation and membrane process. However, a large volume and high energy consumption are needed in biotransformation, while the low permeability and stability must be solved in the membrane process.     

3种酚酸对4种水华微藻生长的影响

通过测定藻细胞密度,分析邻苯二酚、没食子酸和焦性没食子酸的自氧化时间,研究了此3种酚酸对水华束丝藻、颤藻、实球藻和衣藻等4种水华微藻生长的影响。结果表明,当酚酸质量浓度超过3.2 mg/L时,3种酚酸对此4种微藻的生长均有明显的抑制作用。其中,没食子酸和焦性没食子酸对4种微藻的抑制作用比邻苯二酚更为显著。3种酚酸的自氧化测定结果表明,没食子酸和焦性没食子酸在2 h时完全消失;邻苯二酚的自氧化时间较长,约为8 d。根据上述结果,推测此3种酚酸对4种水华微藻的抑制作用很可能与其自氧化能力有关。     

Preparation of free‐standing chitosan membranes for Chlorella vulgaris harvest and examination on suppression of algae‐fouling properties

Free‐standing chitosan membranes were prepared using genipin as crosslinker, using several molecular weights of polyethylene glycol (PEG) as a void‐forming agent. The membrane surface formation and chitosan polymer chain crosslinking were confirmed through SEM and FTIR, respectively. The water flux was remarkably increased with increasing molecular weight of PEG employed in preparation of composite chitosan membrane (J∝[PEG(MW)]0.85), it appeared over 6000 Da of PEG. During Chlorella vulgaris harvest using chitosan membranes, focus was made on algae‐fouling caused by the deposition of cells and extracellular organic matter, and it was found that membranes employing lower molecular weight of PEG (under 10000 Da) had been maintaining the high flux recovery after alternating filtration cycles, in addition to PEG20000 containing membrane. The chitosan membrane prepared with lower molecular weight of PEG exhibited better suppression of algae‐fouling properties. The Chlorella vulgaris harvesting results indicated that cell rejection rate reached above 98%.     

Potential application of microalga Spirulina platensis as a protein source

The high protein level of various microalgal species is one of the main reasons to consider them an unconventional source of this compound. Spirulina platensis stands out for being one of the richest protein sources of microbial origin (460–630 g kg^?1, dry matter basis), having similar protein levels when compared to meat and soybeans. The use of S. platensis in food can bring benefits to human health owing to its chemical composition, since it has high levels of vitamins, minerals, phenolics, essential fatty acids, amino acids and pigments. Furthermore, the development of new protein sources to supply the shortage of this nutrient is an urgent need, and protein from S. platensis plays an important role in this scenario. In this sense, extraction processes that allow maximum protein yield and total utilization of biomass is an urgent need, and ultrasonic waves have proven to be an effective extraction technique. The number of scientific papers related to protein fraction from S. platensis is still limited; thus further studies on its functional and technological properties are needed. © 2016 Society of Chemical Industry     

水处理集成微藻生物柴油生命周期系统环境影响评价

采用生活废水的二级出水培养微藻可有效提高微藻生物柴油生产过程的环境效益，降低其环境影响。本文基于生命周期分析原理，针对结合了废水培养微藻的两种微藻生物柴油生产技术路线，即传统路线和热解酯化路线，建立了环境影响评价模型；提出了水处理集成微藻生物柴油生命周期系统评价的水处理过程替代效应的概念及其环境效益定量评价方法；通过计算对比了基于新鲜水培养微藻的两种技术路线的总环境影响指数和废水培养微藻的两种技术路线的环境效益，表明热解酯化工艺结合废水培养微藻路线相较其他工艺路线具有最小的环境影响，表明水处理过程替代效应在水处理集成微藻生物柴油生命周期系统评价中的有效性和必要性。     

A review on microalgae,a versatile source for sustainable energy and materials

Increasing energy demands, predicted fossil fuels shortage in the near future, and environmental concerns due to the production of greenhouse gas carbon dioxide on their combustion have motivated the search for alternative ‘clean’ energy sources. Among many resources for this, microalgae have been found to be most promising due to their high production capacity of vegetable oils. They possess a high growth rate, need abundantly available solar light and CO₂, and thus are more photosynthetically efficient than oil crops. Also, they tolerate high concentration of salts allowing the use of any type of water for the agriculture and the possibility of production using innovative compact photobioreactors. In addition, microalgae are a potential source of biomass, which may have great biodiversity and consequent variability in their biochemical composition. This paper presents an overview on microalgae with particular emphasis as a source for energy (biofuel/electricity) and new materials. Critical issues involved in production of microalgae and their use, future R & D to overcome these, including the work initiated by the authors at Federal University of Paraná, UFPR, in Brazil are discussed. Copyright © 2010 John Wiley & Sons, Ltd.