Environmental Research Institute, MaREI Centre, University College Cork, Cork, T23 XE10, Ireland; School of Engineering, University College Cork, Cork, Ireland.
Department of Environmental Science, SRM University-AP, Amaravati, Andhra Pradesh 522 502, India.
Biotechnol Adv. 2019 Dec;37(8):107444. doi: 10.1016/j.biotechadv.2019.107444. Epub 2019 Aug 30.
Photosynthetic biogas upgrading using microalgae provides a promising alternative to commercial upgrading processes as it allows for carbon capture and re-use, improving the sustainability of the process in a circular economy system. A two-step absorption column-photobioreactor system employing alkaline carbonate solution and flat plate photobioreactors is proposed. Together with process optimisation, the choice of microalgae species is vital to ensure continuous performance with optimal efficiency. In this paper, in addition to critically assessing the system design and operation conditions for optimisation, five criteria are selected for choosing optimal microalgae species for biogas upgrading. These include: ability for mixotrophic growth; high pH tolerance; external carbonic anhydrase activity; high CO tolerance; and ease of harvesting. Based on such criteria, five common microalgae species were identified as potential candidates. Of these, Spirulina platensis is deemed the most favourable species. An industrial perspective of the technology further reveals the significant challenges for successful commercial application of microalgal upgrading of biogas, including: a significant land footprint; need for decreasing microalgae solution recirculation rate; and selecting preferable microalgae utilisation pathway.
利用微藻进行光合沼气升级为商业升级工艺提供了一种很有前途的替代方法，因为它允许碳的捕获和再利用，从而提高了循环经济系统中该工艺的可持续性。提出了一种两步吸收柱-光生物反应器系统，使用碱性碳酸盐溶液和平板光生物反应器。除了对系统设计和操作条件进行优化评估外，与工艺优化相结合，选择合适的微藻物种对于确保连续性能和最佳效率至关重要。在本文中，除了对系统设计和操作条件进行关键评估以实现优化外，还选择了五个标准来选择最佳的微藻物种进行沼气升级。这些标准包括：混合营养生长能力；高 pH 值耐受性；外碳酸酐酶活性；高 CO 耐受性；以及易于收获。基于这些标准，确定了五种常见的微藻物种作为潜在的候选物种。其中，螺旋藻被认为是最有前途的物种。该技术的工业视角进一步揭示了微藻沼气升级技术成功商业化应用的重大挑战，包括：占地面积大；需要降低微藻溶液的再循环率；以及选择更好的微藻利用途径。
