Journal of Energy Bioscience 2024, Vol.15, No.2, 96-107 http://bioscipublisher.com/index.php/jeb 102 treated municipal wastewater as a growth medium has shown promising results, with certain microalgae strains demonstrating high growth rates and effective nutrient utilization, further reducing the costs associated with cultivation (Reyimu and Özçimen, 2017). 6.2 Advances in genetic engineering of microalgae Genetic engineering has emerged as a powerful tool to enhance the bioethanol production capabilities of microalgae. By manipulating environmental stress responses and stress tolerance, researchers have been able to increase lipid and carbohydrate production, which are critical for bioethanol synthesis. Omics-based technologies have provided deeper insights into gene regulation under stress conditions, enabling targeted genetic modifications to improve production efficiency (Chen et al., 2017). Furthermore, synthetic biology and multi-omics integration have opened new avenues for optimizing metabolic pathways, thereby enhancing the overall yield of bioethanol and other valuable bioproducts (Chen et al., 2017). 6.3 Integrated systems for bioethanol production and wastewater treatment The integration of bioethanol production with wastewater treatment presents a sustainable approach to resource utilization. Microalgae-based systems have been successfully employed to treat various types of wastewater, including dairy and food processing wastewater, while simultaneously producing bioethanol. These integrated systems not only reduce the environmental impact of wastewater but also provide a cost-effective medium for microalgae cultivation (Hemalatha et al., 2019; Chong et al., 2021). Membrane-integrated systems have been particularly effective, offering low-cost and eco-friendly solutions for the separation, purification, and concentration of bioethanol and other valuable by-products (Kumar et al., 2019). This approach aligns with the principles of green chemistry, promoting both high productivity and environmental sustainability (Reyimu and Özçimen, 2017). By leveraging these technological advances, the potential of microalgae in bioethanol production can be fully realized, contributing to a greener and more sustainable future. 7 Economic and Environmental Impact 7.1 Cost analysis of microalgae-based bioethanol production The cost analysis of microalgae-based bioethanol production involves evaluating the expenses associated with the cultivation, harvesting, and processing of microalgae into bioethanol. Studies have shown that the production cost can be significantly reduced by optimizing cultivation methods, selecting appropriate algal species, and utilizing renewable energy sources. For instance, the use of autotrophic cultivated microalgae and the integration of renewable energy sources can lower production costs and environmental impacts (Zhang et al., 2022). Additionally, the use of wastewater for microalgae growth can replace synthetic cultivation mediums, further reducing costs and environmental pressures (Marangon et al., 2021). 7.2 Life cycle assessment (LCA) of microalgal bioethanol Life cycle assessment (LCA) is a crucial tool for evaluating the environmental sustainability of microalgal bioethanol production. Several studies have conducted LCA to assess the energy balance, CO2 emissions, and overall environmental impact of the process. For example, an LCA study in Brunei Darussalam demonstrated a favorable net energy ratio and low CO2 emissions for industrial-scale bioethanol production from microalgae (Hossain et al., 2019). Another study highlighted the environmental benefits of using anaerobic digested wastewater for microalgae cultivation, which resulted in a positive energy conversion efficiency and reduced environmental impact (Li et al., 2020). These assessments underscore the potential of microalgal bioethanol as a sustainable alternative to fossil fuels. 7.3 Environmental benefits and challenges Microalgae-based bioethanol production offers several environmental benefits, including the reduction of greenhouse gas emissions and the utilization of non-arable land and wastewater for cultivation. Microalgae can sequester CO2 and produce valuable bioactive compounds, contributing to a circular bioeconomy (Porcelli et al., 2020). However, challenges remain, such as the high energy consumption during the cultivation and processing stages. For instance, the drying process of microalgae biomass can significantly impact the life cycle and environmental sustainability of the production process (Marangon et al., 2021). Addressing these challenges
RkJQdWJsaXNoZXIy MjQ4ODYzMg==