Photosynthetic CO2-fixation and hydrogen production by marine microalgae

全球气候变暖是当今世界面临的一个紧迫的环境问题，其主要原因是大气中CO_2的增加。利用光合微藻来帮助解决这个问题已经在各种途径中被提出，因为它们的培养能够利用阳光固定CO_2并产生能量和化合物。我们提出了一个生物系统，它可以在微藻和光合细菌的帮助下将阳光转化为氢能。分离到一种具有高放氢活性的海洋绿色藻类和一种海洋光合细菌，并对其氢代谢进行了表征。光合细菌利用藻类细胞分泌的有机物产生H_2，每摩尔淀粉-葡萄糖的H_2转化率高达10.7molH_2。

One of the urgent environmental problems today is the global warming caused mainly by increasing amount of atmospheric CO_2. The use of photosynthetic microalgae to help to solve this problem has been proposed in a variety of approaches, because the cultivation of them is able to fix CO_2 and produce energy and chemical compounds by the use of sunlight. We have proposed a biological system that converts sunlight to hydrogen energy with the aid of microalgae and photosynthetic bacteria. A marine green alga and a marine photosynthetic bacterium both having high H_2 evolution activities have been isolated and characterized with respective to their H_2 metabolism. A low H_2 yield in algal fermentation could be overcome by using the photosynthetic bacterium, because it produces H_2 from organic compounds secreted by the algal cells exhibiting a high conversion yield of 10.7 mol H_2 per mol of starch-glucose.