MoMiX - Modelling Mixotrophy in the extremophile alga Galdieria sulphuraria

硫酸Galdieria suluraria是一种在火山带分离的世界性光合微藻。这种嗜酸和嗜热藻类的特点是高代谢灵活性以及高生物量生产力。G suluraria能够在光养（完全利用光作为能量来源）、异养（发酵或还原性碳呼吸）以及混合营养条件（同时利用光和还原性碳）下生长。硫脲被认为是一种新兴的生物技术应用系统。另一方面，这些独特性能的分子基础在很大程度上仍然未知。因此，我们提出了一个项目，以了解Galdieria混合营养生长的分子机制，作为实现生物技术应用的最大生物量的一步。这将通过在光/混合营养条件下对不同菌株进行高通量筛选（光合作用，生长）来实现。比较基因组学、蛋白质组学以及代谢分析将使得在计算机上重建硫磺藻的代谢成为可能，这要归功于一种新的生物信息学工具，该工具设计用于详细的重建和可视化以及代谢网络的系统范围分析。这将使进行代谢建模和通量平衡分析成为可能，从而确定光和碳源转换中的制约因素和限制步骤。为了实现这些目标，我们组建了一个由三个合作伙伴组成的联盟（LPCV， HHU， BGE），他们在光合生物代谢的研究方面有着坚实的记录，都是各自科学领域的研究领导者。合作实验室为硫藻（G. sulphuraria， HHU）的首次研究做出了贡献，包括测序其基因组，以及确定微藻（LPCV）中混合营养的机制。这三家合作伙伴将利用互补的方法学专长研究混合营养代谢的关键步骤（LPCV：生理学、呼吸和代谢重建；BGE：蛋白质组学、生物信息学；HHU：比较基因组学和代谢通量）。该项目将为如何优化该藻类的生产力提供知识，并从未来代谢工程的角度确定提高生物质生产力的目标。

Galdieria sulphuraria is a cosmopolitan photosynthetic microalga isolated in volcanic zones. This acidophilic and thermophilic alga is characterized by a high metabolic flexibility as well as by a high biomass productivity. G sulphuraria is able to grow in phototrophic regime (exclusive use of light as a source of energy), heterotrophy (fermentation or reduced carbon respiration) as well as in mixotrophic conditions (simultaneous use of light and reduced carbon). G. sulphuraria is considered as an emerging system for Biotech applications. On the other hand, the molecular bases of these unique performances are still largely unknown. For this reason, we propose a project to understand the molecular mechanisms of Galdieria mixotrophic growth as a step towards achieving maximum biomass for biotechnological applications. This will be achieved by high-throughput screening (photosynthesis, growth) of different strains under photo / mixotrophic conditions. Comparative genomics, proteomics as well as metabolic analyses will make it possible to reconstruct in silico the metabolism of G. sulphuraria, thanks to a new bioinformatic tool designed for detailed reconstruction and visualization and system-wide analyses of metabolic networks. This will make it possible to carry out metabolic modelling as well as flux balance analysis, and thus to identify the constraints and the limiting steps in the conversion of light and carbon sources. To achieve these goals, we have assembled a consortium of three partners (LPCV, HHU, BGE) with a solid record in the study of the metabolism of photosynthetic organisms, all leaders of research in their scientific fields. The partner laboratories contributed to the first studies of G. sulphuraria (HHU), including the sequencing of its genome, and the identification of the mechanism of mixotrophy in microalgae (LPCV). The three partners will study the key steps of mixotrophic metabolism with complementary methodological expertise (LPCV: physiology, respiration and metabolic reconstruction; BGE: proteomics, bioinformatics; HHU: comparative genomics and metabolic fluxes).This project will provide knowledge on how to optimize the productivity of this alga and will identify targets for improved biomass productivity from the perspective of future metabolic engineering.