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41.
Potential yields and properties of oil from the hydrothermal liquefaction of microalgae with different biochemical content 总被引:2,自引:0,他引:2
P. BillerA.B. Ross 《Bioresource technology》2011,102(1):215-225
A range of model biochemical components, microalgae and cyanobacteria with different biochemical contents have been liquefied under hydrothermal conditions at 350 °C, ∼200 bar in water, 1 M Na2CO3 and 1 M formic acid. The model compounds include albumin and a soya protein, starch and glucose, the triglyceride from sunflower oil and two amino acids. Microalgae include Chlorella vulgaris,Nannochloropsis occulata and Porphyridium cruentum and the cyanobacteria Spirulina. The yields and product distribution obtained for each model compound have been used to predict the behaviour of microalgae with different biochemical composition and have been validated using microalgae and cyanobacteria. Broad agreement is reached between predictive yields and actual yields for the microalgae based on their biochemical composition. The yields of bio-crude are 5-25 wt.% higher than the lipid content of the algae depending upon biochemical composition. The yields of bio-crude follow the trend lipids > proteins > carbohydrates. 相似文献
42.
《Saudi Journal of Biological Sciences》2022,29(5):3083-3096
Bio-fertilization is a sustainable agricultural practice that includes using bio-fertilizers to increase soil nutrient content resulting in higher productivity. Soil micro-flora has been exposed to improve soil fertility and increase biomass productivity and identified as a correct environmentally friendly bio-based fertilizer for pollution-free agricultural applies. The majority of cyanobacteria can fix nitrogen from the atmosphere and several species including Anabaena sp., Nostoc sp., and Oscillatoria angustissima is known to be effective cyanobacterial based bio fertilizers. Acutodesmus dimorphus, Spirulina platensis Chlorella vulgaris, Scenedesmus dimorphus, Anabaena azolla, and Nostoc sp. are some of the green microalgae and cyanobacteria species that have been successfully used as bio fertilizers to boost crop growth. Also, Chlorella vulgaris is one of the most commonly used microalgae in bio fertilizer studies. The addition of seaweed species that are Sargassum sp. and Gracilaria verrucosa leads to chemical changes as a soil fertility indicator on clay and sandy soils, and the addition of seaweed conditioner to soil can improve its organic content, return pH to normal, and reduce C/N ratio in both sandy and clay soil. This review provides an effective approach to increase soil fertility via environmentally friendly bio-based fertilizer using micro and macro algae. Instead of the usage of inorganic and organic fertilizers that have polluted impacts to soil as aggregation of heavy metals, in addition to there their human carcinogenic effects. 相似文献
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微藻生产油脂培养新技术 总被引:1,自引:0,他引:1
近年来,随着全球性能源短缺和环境污染等问题日益严重,利用微藻开发绿色、清洁的生物能源已成为了研究热点。但是微藻油脂的低合成速率和高成本限制了微藻油脂的大规模生产。为了有效开发利用微藻资源,双阶段及共培养技术被发展并取得了显著进展。此外,除了改变培养条件,更为简单的添加生长代谢调节因子的策略也被证明是一种有效的提高微藻油脂的技术。对各种新发展的微藻培养技术及其技术原理进行了详细介绍,在此基础上,初步展望了微藻产油研究的未来发展方向。 相似文献
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Sulaiman Al‐Zuhair Salman Ashraf Soleiman Hisaindee Naeema Al Darmaki Sinan Battah Dimitri Svistunenko Brandon Reeder Glyn Stanway Afeefa Chaudhary 《Engineering in Life Science》2017,17(2):175-185
Crude proteins and pigments were extracted from different microalgae strains, both marine and freshwater. The effectiveness of enzymatic pre‐treatment prior to protein extraction was evaluated and compared to conventional techniques, including ultrasonication and high‐pressure water extraction. Enzymatic pre‐treatment was chosen as it could be carried out at mild shear conditions and does not subject the proteins to high temperatures, as with the ultrasonication approach. Using enzymatic pre‐treatment, the extracted proteins yields of all tested microalgae strains were approximately 0.7 mg per mg of dry cell weight. These values were comparable to those achieved using a commercial lytic kit. Ultrasonication was not very effective for proteins extraction from Chlorella sp., and the extracted proteins yields did not exceed 0.4 mg per mg of dry cell weight. For other strains, similar yields were achieved by both treatment methods. The time‐course effect of enzymatic incubation on the proteins extraction efficiency was more evident using laccase compared to lysozyme, which suggested that the former enzyme has a slower rate of cell disruption. The crude extracted proteins were fractionated using an ion exchange resin and were analyzed by the electrophoresis technique. They were further tested for their antioxidant activity, the highest of which was about 60% from Nannochloropsis sp. The total phenolic contents in the selected strains were also determined, with Chlorella sp. showing the highest content reaching 17 mg/g. Lysozyme was also found to enhance the extraction of pigments, with Chlorella sp. showing the highest pigments contents of 16.02, 4.59 and 5.22 mg/g of chlorophyll a, chlorophyll b and total carotenoids, respectively. 相似文献
47.
Francine S. Antelo Jorge A.V. Costa Susana J. Kalil 《Biochemical Engineering Journal》2008,41(1):43-47
The cyanobacterium Spirulina platensis is a source of pigments, such as phycocyanin, which is used in the food, cosmetic and pharmaceutical industries. The thermal degradation kinetics of the liquid extract at pH values of 5, 6 and 7 was studied, evaluating its stability between 50 and 65 °C. The kinetic model was assumed and validated as being of the first order. Between 50 and 55 °C the extract was more stable at pH 6 and between 57 and 65 °C at pH 5, but was shown to be increasingly unstable at pH 7 as the temperature of the treatment increased. The addition of sorbitol between 10 and 50% (w/w) in the treatment at 62 °C for 30 min increased the half-life values of the phycocyanin extract, proving that its de-colorization was related to degradation of the protein chain. 相似文献
48.
Microalgae composition, abundance, diversity and biomass of the Qua Iboe Estuary mangrove swamp were studied. The results
revealed the rich assemblage of the brackish ecosystem. Six major taxanomic classes were encountered. These were the Bacillariophyceae,
Cyanophyceae, Chlorophyceae, Chrysophyceae, Euglenophyceae and Phaeophyceae. Their composition, abundance and diversity exhibits
strong seasonal variation. Variations between pelagic and sedimentary habitats were also noticed. The diatoms (Bacillariophyceae)
dominated the habitats. Actinoptychus undalatus, Navicula radiosa and Amphora ovalis co-dominated the pelagic water column; while the epipellic (intertidal) and benthic (subtidal) sediments were co-dominated
by A. ovalis and Actinoptychus undulatus. Analyses of the Shannon’s index of general diversity (H1), McArthur-Terborgh species equitability index (E) and Simpson’s index of dominance (D) of the microalgae communities revealed
that A. ovalis with a mean H
1
-value of 0.25, E-value of 0.08 and D-value of 0.05 was the most prevalent genus in the mangrove ecosystem despite its uneven distribution. The densities of the
microalgae communities corresponded with their biomass statuses and were seriously impacted by oil spillage. This forms the
basis of concern because the estuary is associated with a high probability of major oil pollution with serious consequences
for ecological stability and fisheries. 相似文献
49.
Influence of drought on algal biofilms and meiofaunal assemblages of temperate reservoirs and rivers
Maria-José Caramujo Carlos Rafael B. Mendes Paulo Cartaxana Vanda Brotas Maria-José Boavida 《Hydrobiologia》2008,598(1):77-94
The role of hydrological droughts in shaping meiofauna abundance through alterations in biofilm biomass and composition was
investigated. In January 2005, continental Portugal was under a moderate to severe drought resulting from a 40% to 60% decrease
in rainfall during the previous 12 months relative to the long-term average (1961–1990). Reservoir capacity was reduced by
30–50% relative to average values and the width of streams was reduced by 20–80% in the Zêzere River Basin (central Portugal).
Algal biomass and algal class composition of biofilms was assessed through quantification of algal pigments in three reservoir
and six river locations. During drought, habitat alterations are expected to be sharp in rivers while, in the absence of water
quality deterioration, the habitat characteristics of reservoirs are expected to remain fairly unaffected. Chlorophylls and
carotenoid pigments were extracted from biofilm samples and analysed using high performance liquid chromatography (HPLC).
In the winter of 2003, during the period of average rainfall, biofilm biomass did not exceed 5 μg chlorophyll a cm−2 at any location. River biofilm biomass was roughly half of that measured in the reservoirs. In the winter of 2005 (drought),
biofilm biomass increased by more than 5-fold in river locations and remained low or decreased in the reservoirs. Algal biofilms
were either dominated by Bacillariophyceae or by Chlorophyceae regardless of the existence of drought. The relative contribution
of Bacillariophyceae to total biofilm biomass was higher during the drought than under average hydrological conditions. The
abundance of harpacticoids, cladocerans and ostracods was favoured by the drought only in the reservoirs where an increase
in diatom proportion in biofilms was observed. The increase in the abundance of cyclopoid copepods, turbellarians, nematodes
and chironomids in rivers during the drought could be explained by algal class composition and biomass of biofilms and environmental
variables (organic matter sediment content, phosphorus availability content and sediment granulometry). The hydrological drought
appears to regulate meiofauna abundance only in river locations, possibly through the promotion of the growth of biofilms
and the availability of organic matter deposited in rivers during the drought.
Handling editor: D. Ryder 相似文献
50.