Molecular basis of algal-bacterial interactions and its implications for industrial cultivation of microalgae

藻类-细菌相互作用的分子基础及其对微藻工业化培养的影响

• 批准号: BB/I013164/1
• 负责人: Alison Smith
• 金额: $ 45.58万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2011
• 资助国家: 英国
• 起止时间: 2011 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FI013164%2F1
• 关键词: Molecular; basis; algal; bacterial; interactions

The World is faced with the considerable challenge of supplementing, and ultimately replacing, its fossil fuel-based economy with one based on clean energy technologies such as biofuels. Currently, commercially available biofuels (e.g. bioethanol and biodiesel) are derived from crop plants such as maize and soybean. However, there are major concerns regarding both the use of valuable agricultural land for production of biofuel crops, and the sustainability and energy balance of such technologies. A potential alternative source of biofuels is microalgae - aquatic photosynthetic organisms that do not require fertile land for cultivation; grow considerably faster than plants, and which can accumulate significant quantities of high-energy compounds such as oils. Furthermore, such aquatic cultivation could be coupled to waste streams such as CO2 output from industry and nutrient-rich effluent, thereby using this waste to promote algal growth. However, industrial-scale cultivation of microalgae for biofuels faces considerable challenges, not just in terms of technical feasibility, but also in terms of economics and achieving a net positive energy balance. In particular, although the best rates of productivity of suitable strains are achieved in enclosed tubular systems, called photobioreactors, the energy requirement for building and operating these facilities is much greater than that in the fuel that is extracted. In contrast, growth in open raceway ponds generally results in energy savings compared to fossil-derived diesel. On the other hand, open ponds are at great risk from contamination by bacteria, viruses or competing algae. Crop protection is therefore a key issue that must be addressed to allow effective and productive commercialisation of algae. We have discovered an interaction between microalgae and bacteria that might provide a means to assist in this crop protection. Over half of all species of microalgae require vitamin B12 for growth - and they can obtain it from bacteria, in return for sugars made from photosynthesis. We have identified a possible explanation for why so many algae need this vitamin - it appears that loss of a particular gene, called METE, changes an alga from being effectively a 'hunter-gatherer', using B12 if it is available, to a 'subsistence farmer', needing to cultivate bacteria to ensure a proper supply of this vitamin. This suggests that there must be ways in which the two organisms signal to one another, and also that there is some advantage to this lifestyle, since it is so prevalent. In this project we will test our hypothesis, and determine if the growth of algae and bacteria together in cocultures affect the productivity of fuel molecules in the algal cells, and if it prevents contamination by invasive species. We will also use several molecular approaches to identify genes and proteins that might be involved in this interaction, in particular in the uptake of B12 by the algal cells.

世界面临着巨大的挑战，即以生物燃料等清洁能源技术为基础的经济补充并最终取代以化石燃料为基础的经济。目前，商业上可获得的生物燃料（例如生物乙醇和生物柴油）来源于作物植物，例如玉米和大豆。然而，人们对使用宝贵的农业土地生产生物燃料作物以及这种技术的可持续性和能源平衡都感到严重关切。一种潜在的生物燃料替代来源是微藻-一种水生光合生物，不需要肥沃的土地来种植;生长速度比植物快得多，并且可以积累大量的高能量化合物，如油。此外，这种水产养殖可以与工业产生的二氧化碳和富含营养物的废水等废物流结合起来，从而利用这些废物促进藻类生长。然而，用于生物燃料的微藻工业化规模种植面临着相当大的挑战，不仅在技术可行性方面，而且在经济性和实现净正能量平衡方面。特别是，虽然合适的菌株的最佳生产率是在封闭的管状系统中实现的，称为光生物反应器，但建造和操作这些设施所需的能量远远大于所提取的燃料。相比之下，与化石柴油相比，开放式跑道池塘中的生长通常会节省能源。另一方面，开放的池塘面临着细菌、病毒或竞争藻类污染的巨大风险。因此，作物保护是必须解决的关键问题，以允许藻类的有效和富有成效的商业化。我们已经发现了微藻和细菌之间的相互作用，这可能提供一种帮助作物保护的方法。超过一半的微藻物种需要维生素B12才能生长-它们可以从细菌中获得维生素B12，以换取光合作用产生的糖。我们已经确定了为什么这么多藻类需要这种维生素的一个可能的解释-似乎是一种称为METE的特定基因的丢失，将藻类从有效的“狩猎采集者”（如果有B12的话，使用B12）改变为“自给自足的农民”，需要培养细菌以确保这种维生素的适当供应。这表明，两种生物体之间一定有相互传递信号的方式，而且这种生活方式也有一定的优势，因为它是如此普遍。在这个项目中，我们将测试我们的假设，并确定藻类和细菌在共培养物中的生长是否会影响藻类细胞中燃料分子的生产力，以及是否会防止入侵物种的污染。我们还将使用几种分子方法来鉴定可能参与这种相互作用的基因和蛋白质，特别是在藻类细胞对B12的吸收中。

项目成果

Biotic interactions as drivers of algal origin and evolution

生物相互作用作为藻类起源和进化的驱动力

• DOI: 10.17863/cam.15873
• 发表时间: 2017
• 作者: Brodie J

Exploring the onset of B 12 -based mutualisms using a recently evolved Chlamydomonas auxotroph and B 12 -producing bacteria

使用最近进化的营养缺陷型衣藻和生产 B 12 的细菌探索基于 B 12 的互利共生的开始

• DOI: 10.1101/2022.01.04.474942
• 发表时间: 2022
• 作者: Bunbury F

High-throughput detection of ethanol-producing cyanobacteria in a microdroplet platform.

• DOI: 10.1098/rsif.2015.0216
• 发表时间: 2015-05-06
• 期刊: Journal of the Royal Society, Interface
• 作者: Abalde-Cela S;Gould A;Liu X;Kazamia E;Smith AG;Abell C
• 通讯作者: Abell C

Responses of a Newly Evolved Auxotroph of Chlamydomonas to B12 Deprivation.

新进化的衣藻营养缺陷体对 B12 缺乏的反应。

• DOI: 10.17863/cam.50072
• 发表时间: 2020
• 作者: Bunbury F

Exploring the onset of B12-based mutualisms using a recently evolved Chlamydomonas auxotroph and B12-producing bacteria

使用最近进化的营养缺陷型衣藻和生产 B12 的细菌探索基于 B12 的互利共生的开始

• DOI: 10.17863/cam.84192
• 发表时间: 2022
• 作者: Bunbury F