Optimizing yields of bioproducts in mixotrophic cultures of micro algae

优化微藻混合营养培养物中生物产品的产量

• 批准号: RGPIN-2018-06730
• 负责人: Macintyre, Hugh
• 金额: $ 2.11万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=683205
• 关键词: Optimizing; yields; bioproducts; mixotrophic; cultures

Phytoplankton are single-celled marine and freshwater plants that can be cultivated as sources of valuable natural products. These include lipids (essential nutrients like omega-6 fatty acids but also triacylgylerides, the precursors of biodiesel), proteins that can be used in feedstocks, antioxidants (carotenoids and flavonoids), and potential pharmaceuticals. Mass culture of phytoplankton has also been tested as a means of treating wastewaters that are high in nutrients to remediate eutrophication in watersheds and coastal waters. Coastal eutrophication is responsible for hypoxia and an increased incidence of harmful algal blooms worldwide. Both are environmentally and economically costly.***Many phytoplankton that produce high-value compounds can be grown mixotrophically, a mixed nutritional mode in which the cells are both autotrophic (photosynthetic) and heterotrophic (utilizing labile organic compounds). Mixotrophy can greatly increase growth rates are cell yields but is poorly understood. Consequently, screening for optimal conditions proceeds by trial and error.*** This project will develop a conceptual framework for predicting mixotrophic growth and cell composition as a function of light intensity, temperature, and nutrient availability by extending a widely-used model, the Dynamic Balance model. This would define growth optima for the species used to extend the model, maximizing yield of three high-value compounds. It would also provide a means to focus optimization of conditions for strains producing other valuable compounds in the future.*** Bacterial contamination of mixotrophic culture is more-or-less inevitable and the bacteria can out-compete the phytoplankton for the organic substrates and can cause mass mortality. Suppression of bacterial growth without inhibiting growth of the phytoplankton is therefore essential for economically-feasible cultivation. This project will test use of a proven technology, ultraviolet-C radiation, as a differential stressor that could inhibit bacterial growth without affecting the phytoplankton.*** Last, many valuable products are up-regulated under conditions of stress. Successful cultivation assessing when the culture has reached the optimum condition for harvesting. Bio-optical techniques are ideal for this as they are sensitive to changes in cell composition and function, are non-destructive, and can be used in real time. This project will develop and ground-truth bio-optical signatures that would assess readiness for harvest of cells producing high-value compounds.*** The enhanced production and more efficient screening of strains will facilitate next-generation cultivation of phytoplankton as cell factories for targeted natural products and as means of remediating contaminated wastewaters. This would translate to a novel form of aquaculture and to clearer coastal and inland waters in Canada and worldwide.

浮游植物是单细胞海洋和淡水植物，可以作为有价值的天然产品来源。其中包括脂质（诸如omega-6脂肪酸，以及三酰基酯的必需营养素，生物柴油的前体），可用于原料，抗氧化剂（类胡萝卜素和类黄酮类动物）的蛋白质以及潜在的药物。浮游植物的大规模培养也已被测试，作为治疗养分较高的废水，以补救流域和沿海水域的富营养化。沿海富营养化导致缺氧和全球有害藻类开花的发病率增加。 ***许多产生高价值化合物的植物浮游生物都可以在混合营养模式下种植，其中细胞是自养（光合作用）和异养精神（利用不稳定的有机化合物）。混合植物可以大大提高生长速率是细胞产量，但知识渊博。因此，对最佳条件的筛查是通过反复试验进行的。这将定义用于扩展该模型的物种的生长最佳，从而最大程度地提高了三种高价值化合物的产量。这也将提供一种将来关注未来产生其他有价值化合物的菌株的疾病的方法。***杂亲性培养的细菌污染或不可避免地是不可避免的，并且细菌可以超越植物浮游生物的有机底物，并可能导致质量死亡。因此，抑制细菌生长而不抑制浮游植物的生长对于经济上可行的培养至关重要。该项目将测试验证的技术，紫外线辐射的使用，作为一种差异压力源，可以抑制细菌的生长而不会影响浮游植物。成功培养评估培养何时达到收获的最佳条件。生物光学技术是理想的选择，因为它们对细胞组成和功能的变化敏感，无损，可以实时使用。该项目将开发和基础生物光学特征，以评估收获产生高价值化合物的细胞的准备。这将转化为一种新颖的水产养殖形式，并清除加拿大和全球的沿海和内陆水域。