Environmental optimization of an advanced CO2 capture and utilization biotechnology through multi-scenario and multi-method LCA

Environmental sustainability requires robust technologies capable of addressing gaseous emissions while contributing to carbon capture and resource recovery. The paper presents and discusses the environmental sustainability optimization of an integrated Bio-CCU technology that combines a moving bed biofilm bioreactor (MBBR) with an algal photo-bioreactor (PBR), by applying life cycle assessment (LCA). Beyond assessing three operational scenarios—(i) no membrane, 5000 lx LED (Scenario 1); (ii) membrane, 5000 lx LED (Scenario 2); and (iii) membrane, 8000 lx LED (Scenario 3)—the study performs a structured sensitivity and scenario analysis combined with a cross-comparison of LCA tools and methodologies. Specifically, 39 combinations were analysed by integrating three software platforms and two impact assessment methods (IPCC 2013, ReCiPe 2016). Results indicate that the cultivation stage dominates environmental impacts (> 80% in Scenario 1; > 70% in Scenarios 2–3). Scenario 1 achieved the lowest global warming potential (128 kg CO2eq FU−1), while Scenario 2 minimized energy demand (169.8 kWh FU−1). Scenario 3, with intensified illumination, exhibited the highest energy consumption (+ 7%) and GWP value. Comparative results reveal a systematic variation among software and methods, with ReCiPe 2016 consistently yielding higher values (+ 35% vs IPCC 2013), underscoring the critical influence of methodological choice on LCA outcomes. The study highlights the environmental feasibility of an integrated Bio-CCU technology for air pollution control and the comparison between different LCA tools. The findings provide guidance for researchers, practitioners and policymakers in advancing process optimization and improving actions to enhance environmental sustainability assessment.