Investigating photosynthetic efficiency and nutrient use in marine microalgae (provisional- for admin. purposes only)

鉴于二氧化碳在气候变化中的作用，开发碳效率生物制造解决方案非常重要。微藻（包括蓝藻）是全球食物链的重要组成部分，是主要的初级生产者，并且具有独特的产氧光合作用和CO2固定能力。然而，低光合效率，特别是碳固定每养分使用，是限制在工业环境下。CyanoCapture试图设计一种细长聚球藻PCC 11901（Syn 11901），以最小的营养投入实现最大的碳固定，以期扩大作为点源碳捕获技术的规模。最大化光合效率的途径包括提高Rubisco活性以固定碳、CO2浓缩机制（CCM）和减少其他代谢负担，包括呼吸速率。然而，这些会产生重大的障碍，所以我们期待在进化历史中寻找新的操纵途径。该iCASE侧重于描述蓝藻，颗石藻和prasinophytes的营养利用效率（NUE），对碳固定的工业应用和理解地球历史上贫营养海洋的出现具有影响。感兴趣的主要营养素是磷，因为无机磷储存随着现代农业和工业的出现而迅速耗尽。该项目符合一项大规模的尝试，以了解全球从氮限制到磷限制的转变，以及这对初级生产力的组成和固碳能力意味着什么。该项目旨在：（1）确定光合效率最高的颗石植物和prasinophytes;（2）研究这些菌株与Syn 11901相比的生长速率和元素化学计量（WT和由CyanoCapture提供的感兴趣的工程菌株）;（3）将菌株置于其进化背景中;（4）在最低限度的营养条件下，设计一种光合作用“流线型”蓝藻，使其具有最大的碳固定能力，以最小的能量损失;（5）使用代谢组学和通量组学来阐明这些生物体中的碳通量。BBSRC主题：生物科学促进可再生资源和清洁增长。

Given the role of CO2 in climate change, development of carbon-efficient biomanufacturing solutions is important. Microalgae (including cyanobacteria) are an important part of the global food chain as major primary producers, and are unique in their ability to perform oxygenic photosynthesis and CO2 fixation. However, low photosynthetic efficiency, specifically carbon fixation per nutrient used, is limiting under industrial settings. CyanoCapture seeks to engineer a Synechococcus elongatus, PCC11901 (Syn11901) with maximum carbon fixation for minimum nutrient input, with a view to scale up as a point-source carbon capture technology. Pathways for maximising photosynthetic efficiency include improving Rubisco activity for carbon fixation, CO2 concentrating mechanism (CCM), and reduction of other metabolic burdens including respiration rates. However, these incur significant barriers, so we look to evolutionary history in search of novel avenues for manipulation. This iCASE focuses on characterising nutrient use efficiency (NUE) across cyanobacteria, coccolithophores and prasinophytes, with implications for industrial application of carbon fixation and in understanding the emergence of the oligotrophic ocean in Earth's history. The primary nutrient of interest is phosphorus, as inorganic phosphorous stores have rapidly depleted with the advent of modern agriculture and industry. The project fits into a large-scale attempt to understand the global shift from a nitrogen- to phosphorous-limited planet, and what this will mean for the composition and carbon fixing power of primary productivity.The project aims to: (1) identify the most photosynthetically efficient coccolithophore and prasinophytes; (2) investigate growth rate and elemental stoichiometry of these strains in comparison to Syn11901 (WT and engineered strains of interest provided by CyanoCapture); (3) place the strains into their evolutionary contexts; (4) engineer a photosynthetically 'streamlined' cyanobacterium with maximum carbon fixation for minimum energy loss, under minimal nutrient conditions and; (5) use metabolomics and fluxomics to elucidate carbon flux in these organisms.BBSRC theme: Bioscience for renewable resources and clean growth.