Introducing pyruvate oxidase into the chloroplast of Chlamydomonas reinhardtii increases oxygen cons
Introducing pyruvate oxidase into the chloroplast of Chlamydomonas reinhardtii increases oxygen cons
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DOI：
10.1016/j.ijhydene.2011.05.130
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发表时间：
2011-08
期刊：
影响因子：
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通讯作者：
Fuyu Xu;Weimin Ma;Xin-Guang Zhu
中科院分区：
文献类型：
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作者：
Fuyu Xu;Weimin Ma;Xin-Guang Zhu
在厌氧环境中，单细胞绿色藻类莱茵衣藻（Chlamydiumreinhardtii）可以利用氢化酶产生氢气（H2）。氢酶的活性在分子氧的存在下被抑制，形成了在自养生物中大规模生产氢的主要障碍。在这项研究中，我们设计了一种新的途径来消耗氧气，并相应地促进莱茵衣藻产氢。将大肠杆菌的丙酮酸氧化酶和细长聚球藻PCC 7942的过氧化氢酶基因克隆到莱茵衣藻叶绿体中。这两个外源基因由热休克诱导启动子HSP 70 A/RBCS 2启动子驱动。在连续热激处理后，外源基因表现出较高的表达水平，而转基因藻细胞的生长速率与野生型相比略有抑制。在弱光下，转基因藻细胞比野生型消耗更多的氧气。这导致在密封培养条件下，特别是在弱光条件下，氧含量较低，并显着增加产氢。这些结果表明，丙酮酸氧化酶在莱茵衣藻中表达增加耗氧量，并有可能提高光合作用的氢气生产莱茵衣藻。
In an anaerobic environment, the unicellular green algae Chlamydomonas reinhardtii can produce hydrogen (H2) using hydrogenase. The activity of hydrogenase is inhibited at the presence of molecular oxygen, forming a major barrier for large scale production of hydrogen in autotrophic organisms. In this study, we engineered a novel pathway to consume oxygen and correspondingly promote hydrogen production in Chlamydomonas reinhardtii. The pyruvate oxidase from Escherichia coli and catalase from Synechococcus elongatus PCC 7942 were cloned and integrated into the chloroplast of Chlamydomonas reinhardtii. These two foreign genes are driven by a HSP70A/RBCS2 promoter, a heat shock inducing promoter. After continuous heat shock treatments, the foreign genes showed high expression levels, while the growth rate of transgenic algal cells was slightly inhibited compared to the wild type. Under low light, transgenic algal cells consumed more oxygen than wild type. This resulted in lower oxygen content in sealed culture conditions, especially under low light condition, and dramatically increased hydrogen production. These results demonstrate that pyruvate oxidase expressed in Chlamydomonas reinhardtii increases oxygen consumption and has potential for improving photosynthetic hydrogen production in Chlamydomonas reinhardtii.