Domestication of the green alga Chlorella sorokiniana: reduction of antenna size improves light-use efficiency in a photobioreactor.
Domestication of the green alga Chlorella sorokiniana: reduction of antenna size improves light-use efficiency in a photobioreactor.
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DOI：
10.1186/s13068-014-0157-z
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发表时间：
2014
影响因子：
6.3
通讯作者：
Bassi R
中科院分区：
文献类型：
--
作者：
Cazzaniga S;Dall'Osto L;Szaub J;Scibilia L;Ballottari M;Purton S;Bassi R
利用微藻生物质生产生物燃料是发展可持续和安全能源供应的关键因素之一。在不同的微藻中，小球藻因其高生产力、高脂肪含量和对光生物反应器典型的高光条件的耐受性而受到人们的关注。然而，工业规模种植藻类的经济可行性尚未实现，部分原因是生物限制了生物质产量。一个关键问题是由于光分布不均匀而导致的光利用效率低下，以及多余的吸收光以热量的形式消散。生物燃料生产设施的成功实施需要在光生物反应器中开发具有更高的光利用效率的藻类菌株。这样的驯化策略包括减少吸收截面以增强光的穿透，增加每个叶绿素代谢汇的大小和最小化反馈能量消耗。在这项工作中，我们对耐热、快速生长的小球藻C.sorokiniana进行了随机诱变和表型选择。选择了比野生型(WT)菌株具有更低荧光产量的截短天线突变体(TAMS)。通过高通量荧光视频成像技术筛选出6个可能感兴趣的突变体，其中两个突变体-2和-4的单位细胞叶绿素含量和每个PSII的补体含量约为WT的一半。在分批培养中，-2表现出更高的光子利用效率，在饱和光照下产生比WT更高的Pmax。在实验室规模和室外光生物反应器中培养的-2表现出比WT更高的生产率，在工业光生物反应器中典型的致密细胞悬浮液中的生物量产量高出30%。这些结果表明，在大规模培养条件下，选育低叶绿素含量的突变体可以显著提高红曲霉的光-生物量转化效率。然而，由于该物种缺乏有性繁殖，额外突变的存在可能会影响生长速度，这表明选择应该包括对每个所需表型的多个独立突变的评估。本文的在线版本(doi：10.1186/s130680140157-z)包含补充材料，授权用户可以使用。
The utilization of biomass from microalgae for biofuel production is one of the key elements for the development of a sustainable and secure energy supply. Among the different microalgae, Chlorella species are of interest because of their high productivity, high lipid content, and resistance to the high light conditions typical of photobioreactors. However, the economic feasibility of growing algae at an industrial scale is yet to be realized, in part because of biological constraints that limit biomass yield. A key issue is the inefficient use of light due to uneven light distribution, and the dissipation of excess absorbed light as heat. The successful implementation of biofuel production facilities requires the development of algal strains with enhanced light use efficiency in photobioreactors. Such domestication strategies include decreasing the absorption cross section in order to enhance light penetration, increasing the size of metabolic sinks per chlorophyll and minimizing feedback energy dissipation. In this work we applied random mutagenesis and phenotypic selection to the thermotolerant, fast-growing Chlorella species, C. sorokiniana. Truncated antenna mutants (TAMs) were selected that exhibited a lower fluorescence yield than the wild-type (WT) strain. Six putatively interesting mutants were selected by high throughput fluorescence video imaging, two of which, TAM-2 and TAM-4, were found to have approximately half the chlorophyll content per cell and LHCII complement per PSII with respect to the WT. In batch culture, TAM-2 showed an increased photon use efficiency, yielding a higher Pmax at saturating irradiances with respect to the WT. Cultivation of TAM-2 in both laboratory-scale and outdoor photobioreactors showed higher productivity than WT, with a 30% higher biomass yield in dense cell suspensions typical of industrial photobioreactors. These results suggest that generation of mutants with low chlorophyll content can significantly improve the light-to-biomass conversion efficiency of C. sorokiniana under mass culture conditions. However, owing to the lack of sexual reproduction in this species, the presence of additional mutations might affect growth rate, suggesting that selection should include evaluation of multiple independent mutants for each desired phenotype. The online version of this article (doi:10.1186/s13068-014-0157-z) contains supplementary material, which is available to authorized users.
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影响因子：
3.7
作者：
Croce, Roberta;van Amerongen, Herbert
通讯作者：
van Amerongen, Herbert
影响因子：
4.1
作者：
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11.4
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影响因子：
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影响因子：
3.4
作者：
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通讯作者：
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