Khandelwal Amitap, Chhabra Meenu, Lens Piet N L
Ryan Institute, School of Natural Sciences, University of Galway, Galway, Ireland.
Environmental Biotechnology Lab, Department of Biosciences & Bioengineering, Indian Institute of Technology, Jodhpur, India.
Front Plant Sci. 2023 Feb 10;14:1081108. doi: 10.3389/fpls.2023.1081108. eCollection 2023.
Biofuels hold particular promise as these can replace fossil fuels. Algae, in particular, are envisioned as a sustainable source of third-generation biofuels. Algae also produce several low volume high-value products, which enhance their prospects of use in a biorefinery. Bio-electrochemical systems such as microbial fuel cell (MFC) can be used for algae cultivation and bioelectricity production. MFCs find applications in wastewater treatment, CO sequestration, heavy metal removal and bio-remediation. Oxidation of electron donor by microbial catalysts in the anodic chamber gives electrons (reducing the anode), CO and electrical energy. The electron acceptor at the cathode can be oxygen/NO /NO /metal ions. However, the need for a continuous supply of terminal electron acceptor in the cathode can be eliminated by growing algae in the cathodic chamber, as they produce enough oxygen through photosynthesis. On the other hand, conventional algae cultivation systems require periodic oxygen quenching, which involves further energy consumption and adds cost to the process. Therefore, the integration of algae cultivation and MFC technology can eliminate the need of oxygen quenching and external aeration in the MFC system and thus make the overall process sustainable and a net energy producer. In addition to this, the CO gas produced in the anodic chamber can promote the algal growth in the cathodic chamber. Hence, the energy and cost invested for CO transportation in an open pond system can be saved. In this context, the present review outlines the bottlenecks of first- and second-generation biofuels along with the conventional algae cultivation systems such as open ponds and photobioreactors. Furthermore, it discusses about the process sustainability and efficiency of integrating algae cultivation with MFC technology in detail.
生物燃料具有特殊的前景,因为它们可以替代化石燃料。特别是藻类,被视为第三代生物燃料的可持续来源。藻类还能生产几种少量的高价值产品,这增强了它们在生物精炼厂中的应用前景。生物电化学系统,如微生物燃料电池(MFC),可用于藻类培养和生物电生产。MFC在废水处理、二氧化碳封存、重金属去除和生物修复方面都有应用。在阳极室中,微生物催化剂将电子供体氧化产生电子(使阳极还原)、二氧化碳和电能。阴极的电子受体可以是氧气/一氧化氮/二氧化氮/金属离子。然而,通过在阴极室中培养藻类,可以消除阴极对终端电子受体持续供应的需求,因为藻类通过光合作用产生足够的氧气。另一方面,传统的藻类培养系统需要定期进行氧气淬灭,这会消耗更多能量并增加工艺成本。因此,藻类培养与MFC技术的整合可以消除MFC系统中对氧气淬灭和外部曝气的需求,从而使整个过程具有可持续性并成为净能源生产者。除此之外,阳极室产生的二氧化碳气体可以促进阴极室中藻类的生长。因此,可以节省在开放池塘系统中运输二氧化碳所投入的能量和成本。在此背景下,本综述概述了第一代和第二代生物燃料以及传统藻类培养系统(如开放池塘和光生物反应器)的瓶颈。此外,还详细讨论了藻类培养与MFC技术整合的过程可持续性和效率。