Photosynthetic CO2-fixation and hydrogen production by marine microalgae

全球变暖是当今迫在眉睫的环境问题之一，主要是由大气中二氧化碳含量的增加引起的。利用光合微藻来帮助解决这一问题已经提出了多种方法，因为它们的培养能够利用阳光固定二氧化碳并产生能量和化合物。我们提出了一种利用微藻和光合细菌将太阳光转化为氢能的生物系统。分离出一种具有高H_2进化活性的海洋绿藻和一种海洋光合细菌，并对其H_2代谢进行了表征。利用光合细菌从藻类细胞分泌的有机化合物中产生H_2，每mol淀粉-葡萄糖的转化率高达10.7 mol H_2，可以克服藻类发酵过程中H_2产率低的问题。

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.