培养藻类制取生物能源的研究

能源紧张和环境污染是全世界所面临的共同问题,用藻类替代传统作物生产生物能源是生物质能的重要发展方向之一。文章介绍了国内外对藻类培养条件、光生物反应器型式、藻类基因工程、藻细胞收集方法以及能源藻类生产系统的研究成果。研究认为,以藻类为原料生产生物燃料具有良好的发展前景,并指出了今后能源藻类生长的重点研究方向。     

Numerical Simulation of Light/Dark Cycle Frequency of Microalgae Fluid in a Helical Tubular Photobioreactor for Carbon Dioxide Capture

In the present study, three-dimensional numerical simulations are conducted on hydrodynamics and light-intensity distribution of microalgae fluid flow in a helical tubular photobioreactor for CO₂ capture. The effect of incident direction of the light illumination is discussed and the light/dark cycle frequency experienced by the microalgae fluid in the cross-section of the photobioreactor is investigated. The simulation results reveal the steadily nonhorizontal and unsymmetrical Dean roll-cells of the microalgae fluid flow in the cross-section of the helical tube. The external light projecting onto the helical tubular photobioreactor from the center is a better way for microalgae cultivation. The light/dark cycle frequency of the microalgae fluid flow is calculated based on the light-intensity distribution inside the photobioreactor. The light/dark cycle frequency keeps constant for the same stream trace of the microalgae flow while varies with different flow regions. Meanwhile, the light/dark cycle frequency increases with the increase in microalgae fluid velocity. The suitable demarcation between the light and the dark zone depends on the shape and the location of the Dean roll-cells.     

光生物反应器培养紫球藻及藻粉降血脂的研究

研究了搅拌式光生物反应器中搅拌速度、通气量对紫球藻生长、胞外多糖和藻细胞超微结构的影响．实验结果表明：在特定光照(1000μmolm^-2s^-1)和培养温度(25℃)条件下，当搅拌转速为200r／min、通气量为0．71vvm时，藻生长速度和胞外多糖含量最高；增加通气量有利于藻细胞胞外多糖及生物量的提高．对藻细胞超微结构的观察发现，与摇床培养相比，搅拌式光生物反应器使藻细胞淀粉颗粒明显增多，粘质鞘层变薄，光合片层增多．动物实验表明，紫球藻能明显降低摄食高脂饲料SD大鼠血脂TC、TG、LDL-C水平，并提高HDL-C含量．实验结果预示，紫球藻对预防动脉粥样硬化和冠心病的发生有一定的意义．图2表3参26     

内置LED光源平板型光生物反应器用于微藻培养

为降低光生物反应器(PBR)的光照能耗和提高微藻对光能的利用效率,自制了内置LED光源的平板型光生物反应器,用于绿藻普通小球藻(Chlorella vulgaris)的培养和CO2生物固定.评价了这种新型反应器的进气CO2浓度对生物质产率(BP)、CO2固定速率( )和油脂产率(LP)的影响.经过10d连续培养后,与通入空气的对照组相比,浓度1%~10%的CO2均明显促进微藻生长,BP [0.258和0.263g/(L?d)]、最大 [1.18、1.00gCO2/(L?d)]和指数生长期平均 [0.57、0.62gCO2/(L?d)]的高值均出现在CO2 1%、2.5%处理组中.较高浓度(5%、10%)CO2在培养初期造成酸化现象,导致藻细胞密度和生物量较低.CO2浓度变化对微藻总脂含量(17.81%~23.13%)影响较小,以CO2 2.5%条件下得到微藻油脂产率最大[60.71mg/(L?d)].本研究证明,所设计的平板型PBR能够高效培养用于CO2固定和生物柴油原料生产的微藻.     

固定化藻菌流化床光生物反应器处理饮料废水

在自制的流化床光生物反应器中加入固定化藻菌小球来处理饮料废水,主要探讨了反应器中气速、液速以及固定化藻菌小球密度对系统去处效率的影响。在平均停留时间为6h,光照强度为4000lx,温度为室温,试验结果表明:COD的去除率最高可达到91.8%,NH+4-N的去除率最高可达到89.4%,对BOD、PO43--P的去除率也达到较好的效果,分别达到72.1%～85.5%和59.5%～68.0%。     

CO<Subscript>2</Subscript> Mitigation and Renewable Oil from Photosynthetic Microbes: A New Appraisal

The only major strategy now being seriously considered for biological mitigation of atmospheric CO₂ relies entirely on terrestrial plants. Photosynthetic microbes were the focus of similar consideration in the 1990s. However, two major government-sponsored research programs in Japan and the USA concluded that the requisite technology was not feasible, and those programs were terminated after investing US$117 million and US$25 million, respectively. We report here on the results of a privately funded US$20 million program that has engineered, built, and successfully operated a commercial-scale (2 ha), modular, production system for photosynthetic microbes. The production system couples photobioreactors with open ponds in a two-stage process – a combination that was suggested, but never attempted – and has operated continuously for several years to produce Haematococcus pluvialis. The annually averaged rate of achieved microbial oil production from H. pluvialis is equivalent to <420 GJ ha ^-1 yr^-1, which exceeds the most optimistic estimates of biofuel production from plantations of terrestrial ``energy crops.' The maximum production rate achieved to date is equivalent to 1014 GJ ha^-1 yr^-1. We present evidence to demonstrate that a rate of 3200 GJ ha^-1 yr^-1 is feasible using species with known performance characteristics under conditions that prevail in the existing production system. At this rate, it is possible to replace reliance on current fossil fuel usage equivalent to ∼300 EJ yr^-1 – and eliminate fossil fuel emissions of CO₂ of ∼6.5 GtC yr^-1 – using only 7.3% of the surplus arable land projected to be available by 2050. By comparison, most projections of biofuels production from terrestrial energy crops would require in excess of 80% of surplus arable land. Oil production cost is estimated at $84/bbl, assuming no improvements in current technology. We suggest enhancements that could reduce cost to $50/bbl or less.     

光合细菌生物制氢反应器研究进展

光合细菌生物制氢技术,是将太阳能利用和环境治理结合起来的可再生能源生产技术,具有良好的环境效益、社会效益和经济效益.光合细菌制氢反应器研究是将该技术引向产业化的关键步骤.本文列举了目前光合细菌制氢研究中典型的反应器型式,分析了各自的优缺点;总结了反应器高效产氢所必需保证的运行操作条件,如光照强度、温度、pH值等,指出了目前研究中存在的不足;给出了规模化光合细菌生物制氢时需要用到的反应器性能评价指标.并针对目前反应器的研究现状,提出了后续研究应当遵循的方向.     

利用侧光光纤优化生物反应器固定CO_2的研究

为了研究Chlorella sp.固定CO2的效果,降低能耗,采用自制生物光照反应器并选用侧光光纤作为光源。实验结果表明,在适宜条件下,通入浓度为10%CO2后,Chlorella sp.的生长明显加快。当选择红光和蓝光作为侧光光纤的光源交替运行,2 mm与3 mm光纤各28根耦合于16 W的光源发生器,较120 W LED外置光源而言,每瓦可提升6倍的生长速率。