The universality of improved CO2 fixing upon the addition of mixed electron donors（MEDs）composed of Na2 S,NO2-,and S2O32-to non-photosynthetic microbial communities（NPMCs）obtained from 12 locations in four oceans of the world was validated. The CO2 fixing efficiencies of NPMCs were universally enhanced by MED compared with those obtained using H2 alone as electron donor,with average increase of about 276%. An increase in microbial inoculation concentration could increase the net amount of CO2 fixing to853.34 mg/L in the presence of MED. NO2-and S2O32-may play the roles of both electron acceptor and electron donor under aerobic conditions,which may improve the energy utilization efficiency of NPMC and enhance the CO2 fixation efficiency. The sequence determination of 16 S ribosomal deoxyribonucleic acid（rDNA） from 150 bacteria of NPMC showed that more than 50% of the bacteria were symbiotic and there were many heterotrophic bacteria such as Vibrio natriegens. These results indicate that NPMC acts as a symbiotic CO2 fixing system. The interaction between autotrophic and heterotrophic bacteria may be a crucial factor supporting ladder utilization and recycling of energy/carbon source.
Jiajun HuLei WangShiping ZhangYuanqing WangFangming JinXiaohua FuHuirong Li
以基因工程强化微藻三酰甘油(TAG)积累是实现微藻生物柴油应用化的途径之一。为进行有效的基因工程操作,研究分析了微藻代谢网络,以找出其中对TAG合成重要的反应。构建了异养及自养条件下小球藻产TAG过程核心代谢网络。采用改进CASOP(Computational approach for strain optimization aiming at high productivity)法分析网络中各反应的重要度。结果表明,主要的关键反应包括脂肪酸和TAG的合成反应以及提供NADPH的反应,特别是将NADH转化为NADPH的反应。此外,分析结果也部分解释了环境压力对TAG积累的作用。
