Fixation of Carbon Dioxide and Evolution of Clean Biogases by Freshwater Microalgae

在过去的几十年中，大气中二氧化碳的浓度迅速增加，微藻的固碳作用现在得到了深入的研究，但固定碳的利用可能是另一个问题。利用从淡水生态系统（包括水田和池塘）中分离的温带和热带菌株，研究了蓝绿藻等微藻生产氢气和其他清洁沼气。筛选了固定二氧化碳和产氢能力强的菌株。通过观察其生长曲线，考察了光照强度、温度和二氧化碳浓度对其生长的影响。测定叶绿素含量以评价其生长效率和产气效率。在高二氧化碳浓度条件下，产氢能力下降。而无论光强如何，蓝藻中每单位重量叶绿素的产氢量几乎不变。进一步的研究需要从这些研究结果中变得清晰。

Concentration of carbon dioxide in the atmosphere has beenincreased rapidly during past decades Carbon fixation by microalgaeis now intensively studied, but utilization of fixed carbon may be another problem. Production of hydrogen and other clean biogases by microalgae such as blue-green algae (cyanobacteria) were studied by using temperate and tropical strains isolated from freshwater ecosystems, including paddy fields and ponds. Strains with high abilities of fixing carbon dioxide and producing hydrogen were screened. Effect of light intensity, temperature and concentration of carbon dioxide were investigated by examining their growth curves. Chlorophyll contents were determined to evaluate efficiencies of growth and biogases production. Hydrogen production ability depressed under high carbon dioxide concentration conditions. While hydrogen production per unit weight of chlorophyll in cyanobacteria were almost constant regardless of light intensities. Further needs for research became clear from these results of this study.