Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, PR China.
Bioresour Technol. 2010 Apr;101(7):2287-93. doi: 10.1016/j.biortech.2009.11.041. Epub 2009 Dec 5.
In this study, a photosynthesis-fermentation model was proposed to merge the positive aspects of autotrophs and heterotrophs. Microalga Chlorella protothecoides was grown autotrophically for CO(2) fixation and then metabolized heterotrophically for oil accumulation. Compared to typical heterotrophic metabolism, 69% higher lipid yield on glucose was achieved at the fermentation stage in the photosynthesis-fermentation model. An elementary flux mode study suggested that the enzyme Rubisco-catalyzed CO(2) re-fixation, enhancing carbon efficiency from sugar to oil. This result may explain the higher lipid yield. In this new model, 61.5% less CO(2) was released compared with typical heterotrophic metabolism. Immunoblotting and activity assay further showed that Rubisco functioned in sugar-bleaching cells at the fermentation stage. Overall, the photosynthesis-fermentation model with double CO(2) fixation in both photosynthesis and fermentation stages, enhances carbon conversion ratio of sugar to oil and thus provides an efficient approach for the production of algal lipid.
在本研究中，提出了一种光合作用-发酵模型，将自养生物和异养生物的优点结合在一起。小球藻（Chlorella protothecoides）先进行自养生长以固定 CO2，然后再异养生长以积累油脂。与典型的异养代谢相比，在光合作用-发酵模型的发酵阶段，葡萄糖的产油率提高了 69%。基元通量模式研究表明，Rubisco 酶催化的 CO2 再固定提高了从糖到油的碳效率。这一结果可能解释了更高的产油率。在这个新模型中，与典型的异养代谢相比，CO2 的排放量减少了 61.5%。免疫印迹和活性测定进一步表明，Rubisco 在发酵阶段的糖漂白细胞中发挥作用。总的来说，在光合作用和发酵阶段都进行双重 CO2 固定的光合作用-发酵模型，提高了糖到油的碳转化率，从而为藻类油脂的生产提供了一种有效的方法。
