A Preliminary Life Cycle Analysis of Bioethanol Production Using Seawater in a Coastal Biorefinery Setting

Abstract

Bioethanol has many environmental and practical benefits as a transportation fuel. It is one of the best alternatives to replace fossil fuels due to its liquid nature, which is similar to the gasoline and diesel fuels traditionally used in transportation. In addition, bioethanol production technology has the capacity for negative carbon emissions, which is vital for solving the current global warming dilemma. However, conventional bioethanol production takes place based on an inland site and relies on freshwater and edible crops (or land suitable for edible crop production) for production, which has led to the food vs. fuel debate. Establishing a coastal marine biorefinery (CMB) system for bioethanol production that is based on coastal sites and relies on marine resources (seawater, marine biomass and marine yeast) could be the ultimate solution. In this paper, we aim to evaluate the environmental impact of using seawater for bioethanol production at coastal locations as a step toward the evaluation of a CMB system. Hence, a life cycle assessment for bioethanol production was conducted using the proposed scenario, named Coastal Seawater, and compared to the conventional scenario, named Inland Freshwater (IF). The impact of each scenario in relation to climate change, water depletion, land use and fossil depletion was studied for comparison. The Coastal Seawater scenario demonstrated an improvement upon the conventional scenario in all the selected impact categories. In particular, the use of seawater in the process had a significant effect on water depletion, showing an impact reduction of 31.2%. Furthermore, reductions were demonstrated in natural land transformation, climate change and fossil depletion of 5.5%, 3.5% and 4.2%, respectively. This indicates the positive impact of using seawater and coastal locations for bioethanol production and encourages research to investigate the CMB system.

Press water from the mechanical drying of Douglas-fir wood chips has multiple beneficial effects on lignocellulolytic fungi

“…On the other hand, higher COD values, which translate to higher concentrations of substrates, would be beneficial for fungal fermentations. In parallel, PW utilization in the cultivations could reduce the need for freshwater, which is an important aspect for a more sustainable industry [ 60 ].…”

Growth-Promoting Effects of Press Water from the Mechanical Drying of Douglas-Fir Wood Chips on Lignocellulolytic Fungi

“…Thus, higher COD and PW volumes, which translate to higher concentrations of substrates, would be bene cial for fungal fermentations. In parallel, the utilization of the PW would reduce the need for freshwater in the fermentation process, which is an important aspect for a more sustainable industry [54].…”

Introducing a Marine Biorefinery System for the Integrated Production of Biofuels, High-Value-Chemicals, and Co-Products: A Path Forward to a Sustainable Future

“…A specific HPLC method was developed to determine sugars, salts, organic acids, ethanol, and other alcohols in seawater-based samples [10]. In addition, a preliminary life cycle analysis (LCA) of the production of bioethanol using seawater in a coastal setting showed the potential for significant improvement on 15 out of 18 ReCiPe midpoint impact categories including climate change, water depletion, land use, and fossil fuel depletion compared with those of conventional inland-freshwater bioethanol production [11]. Building upon these findings, intensive investigation of bioethanol production from the conventional first-and second-generation biomass using the CBS system (seawater, marine yeast, and terrestrial biomass) is required to confirm the positive role of replacing freshwater with seawater in the fermentation process.…”