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Unicellular microalgae generally grow in the presence of bacteria, particularly when they are farmed massively. This study
analyzes the bacteria associated with mass culture of Botryococcus braunii: both the planktonic bacteria in the water column and those forming biofilms adhered to the surface of the microalgal cells
(∼107–108 culturable cells per gram microalgae). Furthermore, we identified the culturable bacteria forming a biofilm in the microalgal
cells by 16S rDNA sequencing. At least eight different culturable species of bacteria were detected in the biofilm and were
evaluated for the presence of quorum-sensing signals in these bacteria. Few studies have considered the implications of this
phenomenon as regards the interaction between bacteria and microalgae. Production of C4-AHL and C6-AHL were detected in two
species, Pseudomonas sp. and Rhizobium sp., which are present in the bacterial biofilm associated with B. braunii. This type of signal was not detected in the planktonic bacteria isolated from the water. We also noted that the bacterium,
Rhizobium sp., acted as a probiotic bacterium and significantly encouraged the growth of B. braunii. A direct application of these beneficial bacteria associated with B. braunii could be, to use them like inoculants for large-scale microalgal cultures. They could optimize biomass production by enhancing
growth, particularly in this microalga that has a low growth rate. 相似文献
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Bermejo Elisabeth González Cristina Montero-Lobato Zaida Vílchez Carlos Garbayo Inés Cuaresma María 《Journal of applied phycology》2021,33(4):1939-1948
Journal of Applied Phycology - Agricultural fertilisers (NPKs) have been recognised as an alternative to make microalgae cultivation cheaper as well as simpler in terms of the preparation of the... 相似文献
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As a potential source of biofuel, the green colonial microalga Botryococcus braunii produces large amounts of hydrocarbons that are accumulated in the extracellular matrix. Generally, pretreatment such as drying or heating of wet algae is needed for sufficient recoveries of hydrocarbons from B. braunii using organic solvents. In this study, the Showa strain of B. braunii was cultured in media derived from the modified Chu13 medium by supplying artificial seawater, natural seawater, or NaCl. After a certain period of culture in the media with an osmotic pressure corresponding to 1/4-seawater, hydrocarbon recovery rates exceeding 90% were obtained by simply mixing intact wet algae with n-hexane without any pretreatments and the results using the present culture conditions indicate the potential for hydrocarbon milking.
Highlights
Seawater was used for efficient hydrocarbon extraction from Botryococcus braunii. The alga was cultured in media prepared with seawater or NaCl. Hydrocarbon recovery rate exceeding 90% was obtained without any pretreatment. 相似文献5.
在石油资源日趋枯竭、能源需求量日益扩大和油品结构性矛盾长期存在的多重压力下,寻找和开发柴油替代能源对保障我国的能源安全、促进国家经济社会可持续发展具有重要战略意义。葡萄藻是一种世界性分布的淡水或微咸水单细胞微藻,富含烃类、油脂和其它化学物质,而且含烃量可高达细胞干重的86%,是一种潜在的能源微藻。论文综述了近年来有关葡萄藻研究的各个方面的进展,主要内容包括葡萄藻的分类学地位、葡萄藻的细胞学特征、烃类的合成途径、葡萄藻产烃的调控因素以及葡萄藻的收集和烃类的回收途径等,期望为葡萄藻的合理开发利用提供参考。 相似文献
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The green unicellular alga Botryococcus braunii shows unusually high concentrations of non-isoprenoid very long chain hydrocarbons. The structure of such hydrocarbons, the relative efficiency of various long chain fatty acids as precursors, the relationship between fatty acid and hydrocarbon concentrations (over the different physiological stages of the alga achieved during batch cultures) and the preferential localization of fatty acids lead to the conclusion that all the major non-isoprenoid hydrocarbons of B. braunii derive from the same direct precursor, oleic acid. Feeding experiments, using doubly labelled oleic acid, show that the whole carbon chain of the latter is incorporated into final hydrocarbons; accordingly such compounds do not originate from a head-to-head condensation mechanism with oleic acid acting as donor. Various features (regarding chiefly the systematic occurrence of a terminal double bond in B. braunii hydrocarbon, their close specific activities after feeding and the large inhibition in their production achieved using dithioerythritol) show that the biosynthesis of B. braunii hydrocarbons probably takes place via an elongation-decarboxylation mechanism related to that operating in some higher plants. 相似文献
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The production of labelled aliphatic hydrocarbons in Anacystis montana and Botryococcus braunii has been studied using Na2CO3 [14C] as a carbon source. The major hydrocarbon produced by A. montana is pentadecane (ca 93%) accompanied by a pentadecene (ca 4%) and other hydrocarbons in the range C13-C17. Long chain (C21-C 33) hydrocarbons could not be detected in this organism. The variety of unsaturated hydrocarbons (C25-C31) previously reported in Botryococcus braunii is confirmed and contrasts with the synthesis of unsaturated C17 hydrocarbons only, in axenic cultures prepared from single cell isolates of this colonial alga. 相似文献
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Echinenone has been used as an edible orange pigment, antioxidant and provitamin A. An echinenone-accumulating strain, BOT-20, of Botryococcus braunii was isolated from freshwater environments in Japan. The B. braunii BOT-20 strain is different from other strains of B. braunii, as it appeared dark red during its growth in the laboratory culture as opposed to green. The biomass of the strain was 1.9?g?L?1 at 1?month after cultivation. The n-hexane/acetone (3:1, v/v) extract of the strain was 45.5% of the dry biomass weight and consisted of carotenoids (92%, of which 73% was echinenone) and hydrocarbons (8%). The echinenone content was 30.5% of the dry biomass weight, and production was 630?mg?L?1. Hydrocarbons comprised only 3.7% of the total dry biomass weight. The main component of hydrocarbon was an analogue of botryococene by 1H and 13C NMR. With high values of echinenone content and production, the B. braunii strain BOT-20 is expected to be a new bioresource for the commercial production of echinenone. 相似文献
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Jazmin Bazaes Claudia Sepulveda F. Gabriel Acién Juan Morales Leonel Gonzales Mariella Rivas Carlos Riquelme 《Journal of applied phycology》2012,24(6):1353-1360
In this paper, the outdoor production of Botryococcus braunii in pilot-scale panel reactors (0.4?m3) is studied under uncontrolled conditions at a location close to the Atacama Desert (Chile). Discontinuous experiments were performed on different dates to determine the feasibility of the culture and the influence of environmental conditions on the system yield. Data showed that solar radiation is a major parameter in determining system yield, the average irradiance inside the culture determining both the growth rate and biomass productivity. A maximum specific growth rate of 0.09?day?1 and biomass productivity of 0.02?g?L?1?day?1 (dry weight) were measured in discontinuous mode, at an average irradiance of 60?μE?m?2?s?1. With respect to lipids, a productivity of 2.5?mg?L?1?day?1 was obtained under favourable growth conditions; no accumulation of lipids at the stationary phase was observed. To confirm this behaviour, a semicontinuous culture was performed at 0.04?day?1 in a larger reactor (1?m3). In this experiment, the biomass concentration and productivity was 0.3?g?L?1 and 0.015?g?L?1?day?1, respectively. The lipid content and productivity was 15.6% and 2.4?mg?L?1?day?1, respectively, the mean average irradiance inside the reactor being 60?μmol photons?m?2?s?1. The light path of the reactor determines the light availability, thus determining also the biomass concentration and productivity of the reactor once the dilution rate is fixed. Experimentally, biomass productivity of 0.015?g?L?1?day?1 was determined for a light path of 0.15?m, but this can be increased by more than three times for a light path of 0.1?m. These data confirm that this alga can be produced outdoors in a secure form, the culture yield improving when optimal conditions are applied, the data reported here establishing the starting point for the development of the process. 相似文献
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通过对布朗葡萄藻分别在Chu13、Chu13×2和BG-11培养基中培养结果的比较,发现在气升式光照生物反应器中Chu13培养基最有利于布朗葡萄藻的生长和烃的合成,培养15d后,其生物量和粗烃质量分数分别为1.82g/L和58.7%;棕榈酸、油酸和亚麻酸是布朗葡萄藻的主要脂肪酸组成,Chu13培养获得的藻体不饱和脂肪酸比例最高。Chu13培养基中布朗葡萄藻代谢规律的研究表明:粗烃含量随着生物量的增加而逐渐增大,15d后粗烃产量达到最大值1.07g/L,不同生长周期烃的组成保持一致,布朗葡萄藻的烃主要由C33H56和C34H58组成;在布朗葡萄藻生长周期中,不饱和脂肪酸的比例显著上升,培养15d达到64%以上。 相似文献
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Growth of the hydrocarbon-rich microalga Botryococcus braunii in secondarily treated sewage 总被引:6,自引:0,他引:6
Shigeki Sawayama Tomoaki Minowa Yutaka Dote Shinya Yokoyama 《Applied microbiology and biotechnology》1992,38(1):135-138
Summary A hydrocarbon-rich green microalga, Botryococcus braunii, was able to grow well in secondarily treated sewage (STS) from domestic waste-water in a batch system. The growth in STS from domestic waste-water was as good as in the common artificial medium of modified Chu 13 and its hydrocarbon contents were high enough at 53% and 40% compared with 58% in the case of the modified Chu 13 medium. B. braunii utilized nitrate from 7.67 or 4.48 mg/l to a level below detection of < 0.01 mg/l in STS. After this consumption of nitrate, nitrite was consumed, and ammonium was not. Phosphate, even at an extremely low concentration, was also consumed by B. braunii. These results show the possibility of using STS as a medium to grow B. braunii and for removal of nitrogen and phosphorus by algal consumption in STS.Correspondence to: S. Yokoyama 相似文献
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研究了布朗葡萄藻(Botryococcus braunii)764株和765株在3种培养基Chu10、Chu13×2和SE中的生长效应.结果表明:(1)B.braunii764在Chu10中的细胞密度、生物量、总脂含量和总烃含量均高于Chu13×2和SE;B.braunii765在Chu10中的细胞密度、生物量和总脂含量高于Chu13×2和SE,而总烃含量在Chu13×2中较高.(2)B.braunii764的总脂和总烃含量分别为19.4%、23.4%,显著高于B.braunii765. 相似文献
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6 种无机絮凝剂对布朗葡萄藻的絮凝效应 总被引:1,自引:0,他引:1
探讨了6种无机絮凝剂对布朗葡萄藻的絮凝效应。采用光密度法测定布朗葡萄藻的生物量,分别研究了硫酸铝、硫酸铝铵、硫酸铝钾、硫酸镁、硫酸铁、氯化铁对布朗葡萄藻的絮凝效应。结果表明,光密度法可应用于布朗葡萄藻生物量的测定,可间接测定絮凝效应,且最佳测定波长为680nm;6种无机絮凝刺的絮凝时间为60min,同时6种无机试剂对布朗葡萄藻均有明显的絮凝效应,硫酸铝、硫酸铝钾、氯化铁对布朗葡萄藻的絮凝效应较硫酸铝铵、硫酸镁、硫酸铁明显(P〈0.05)。硫酸铝浓度控制在1.1g/L,硫酸铝钾浓度控制在0.45g/L以内,氯化铁浓度控制在0.9g/L。 相似文献
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Navid R. Moheimani Ralf Cord-Ruwisch Eric Raes Michael A. Borowitzka 《Journal of applied phycology》2013,25(6):1653-1661
Some of the key reasons for why the production of biofuels from microalgae have not yet succeeded as a source of sustainable transport fuel are the costs involved and the amount of energy needed to obtain the oils compared to the energy contained in the final fuel. The key energy costs are in the dewatering of biomass followed by extraction of the oil, disposal of biomass, and the energy content of the nutrient fertiliser needed for regrowing the algae. In this study, we bypass all of these barriers by using a different approach towards cutting energy and fertiliser costs in the production of biofuels from microalgae—rather than growing the algae in the presence of fertilisers such as N and P, followed by harvesting the whole algae cells, and the energetically costly drying of cells and extraction of the fuel from the cells, this process makes use of the natural tendency of the green alga, Botryococcus braunii to release oils from the cell into the extracellular matrix during and after growth. Here, we non-destructively and repeatedly harvest the external oil (hydrocarbons) from B. braunii CCAP 807/2. Extraction with several solvents showed that hexane was not compatible with B. braunii, but that heptane in contact with B. braunii for less than 20 min did not negatively affect this alga. As an alternative, solvent-free method, we tested physical methods of extracting the extracellular oil. Light and temperature did not affect the extraction of the external oil from Botryococcus, but gentle pressure (i.e. ‘blotting’) was an effective method for external oil recovery. Less than 1 h of blotting also did not affect the physiology of Botryococcus. Both the heptane extraction and the non-destructive ‘blotting’ methods had no significant effect on growth and photosynthesis (F v/F m, ETRmax) of B. braunii. Our results indicate that over a period of 6 days, we can repeatedly extract over 35 % (using heptane) and 1 % (using ‘blotting’) of the total oil, mainly in the form of external hydrocarbon in stationary phase cells without damage to the cells. 相似文献
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呈串状集落生的丛粒藻(Botryococcus braunii Kiitzig,1989),又译葡萄藻,是一种在温带、热带和大陆性气候带的陆地、淡水和微咸湖水等地广为分布的单细胞绿色微藻(microalgae)。在培养物中,其产烃量为生物量干重的0.3%~76%,通常为25%~40%;在天然样品中,最高达86%,大大高于其它微生物的含烃量(几乎都低于1%)。在国外,从晚远古代(约10~9年前)到近代的沉积岩中,在我国的北部湾沿岸、渤海湾沿岸和茂名油页岩等石油沉积层中,均发现了它的化石。也从云南抚仙湖中得到了该藻。由于在一些石油沉积中几乎全部有机质都是该藻形成的,故美其名曰“油藻”。 相似文献
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布朗葡萄藻是一种含脂量高、开发潜力大的能源微藻,但因其细胞呈集落态且胞壁较坚厚,应用传统的尼罗红荧光光谱法测定其脂质含量时,通常因灵敏度低、重复性差而难以获得可靠结果.本研究通过超声波分散集落、二甲基亚砜辅助尼罗红进入细胞、优化染色条件,有效地解决了上述问题.具体方法为:藻液先经频率为20 kHz、发射功率为100 W的超声波按1 s/1 s(开/关)间歇处理20 s使细胞分散,而后依次加入与藻液等体积的15%二甲基亚砜溶液和3μg/mL尼罗红溶液,充分混匀后于黑暗中40℃染色10min,再于490nm激发光下进行荧光光谱检测.上述改进方法与传统方法相比,检测灵敏度提高了196.6%,反映检测重复性的相对标准偏差(RSD)由10.91%降至1.84%.该方法为布朗葡萄藻育种与培养等研究提供了快速、灵敏的脂质含量检测技术. 相似文献