کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8085641 | 1521800 | 2018 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Overcoming the expression barrier of the ferredoxinâhydrogenase chimera in Chlamydomonas reinhardtii supports a linear increment in photosynthetic hydrogen output
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی انرژی
انرژی های تجدید پذیر، توسعه پایدار و محیط زیست
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چکیده انگلیسی
While the prospect of producing hydrogen from photosynthetic microalgae has long been described as one of the promising directions towards achieving a renewable fuel source, current endeavors towards this goal face serious limitations including the inefficient electron supply to hydrogenase and the enzyme's sensitivity to molecular oxygen. In this work we express our ferredoxinâhydrogenase (fd-hyd) fusion enzyme in a hydrogenase knockout Chlamydomonas reinhardtii mutant and compare its hydrogen production traits to those of wild-type strains. We found that the active enzyme abundance in both systems is in linear correlation with photosynthetic hydrogen production, thus establishing that protein abundance is an additional important bottleneck in the process of hydrogen photo-production. We report here the isolation of two clones with high expression of fd-hyd; OP68 and R2D2, created by either nuclear or chloroplast transformation, respectively. The study of these clones shows that fd-hyd's roughly 4.5-fold higher H2 production efficiency, compared to the native hydrogenase, is maintained in high expression regimes. By comparing a strain's active enzyme pool to its total protein amount, we observed that the engineered clones harbor a large non-mature enzyme pool, indicating that natural maturation of the fd-hyd saturates at a lower level than the native hydrogenase. Subsequently, we measured mRNA levels by quantitative PCR and observed that while the two clones express roughly the same amount of protein, R2D2 has considerably more mRNA. Thus improving transcription rates in nuclear transformants or translation efficiency in chloroplast transformants are both potential routes towards further increasing protein abundance. Finally, we show that these clones are able to continuously produce H2 in sealed bioreactors for five days, significantly outcompeting their parental wild-type strain.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Algal Research - Volume 33, July 2018, Pages 310-315
Journal: Algal Research - Volume 33, July 2018, Pages 310-315
نویسندگان
Iddo Weiner, Noam Shahar, Yael Feldman, Shira Landman, Yuval Milrad, Oren Ben-Zvi, Meital Avitan, Eyal Dafni, Shira Schweitzer, Haviva Eilenberg, Shimshi Atar, Alon Diament, Tamir Tuller, Iftach Yacoby,