Carbon Footprint Assessment of Carrageenan-Based Bioplastic

Abstract

This study presents a carbon footprint assessment of a carrageenan-based bioplastic derived from red seaweed. These bioplastics are biodegradable, renewable, and non-toxic. The analysis evaluates the production of 1 kg of bioplastic film, from seaweed cultivation to final production. A 20% extraction rate was used as the baseline model, while uncertainty analysis using scenarios, namely (i) scenario A (20% extraction + wastewater treatment), (ii) scenario B (10% extraction rate), and (iii) scenario C (scenario B + wastewater treatment), was added. Seaweed cultivation acts as a carbon sink, producing net negative CO₂ emissions in the baseline scenario (-170.72 kg CO₂ eq). Scenario B, where lower extraction rates require more seaweed, enhancing CO₂ absorption but increasing emissions from processing, yielded a total of -353.28 kg CO₂ eq. Wastewater treatment significantly raises emissions, with scenario A at 1169.39 kg CO₂ eq. and scenario C at 2312.61 kg CO₂ eq. Carrageenan powder production is the primary emission contributor (78.35%), followed by bioplastic film production (5.59%). The drying stage contributes less than 0.1%. While seaweed-based bioplastics offer strong sustainability potential due to carbon sequestration, waste emissions from carrageenan extraction and fossil-fuel-based energy use substantially impact the overall carbon footprint. Optimizing extraction efficiency and reducing energy use are critical to enhancing the environmental benefits of these bioplastics as alternatives to conventional plastics.

Keywords