Work

Understanding the biodegradation of PHBV/Cellulose composites in mesophilic anaerobic digestion

Year: 2024

Type: article

Abstract: Biodegradable plastics have been developed as alternative materials to prevent the environmental damage of conventional plastics on ecosystems. However, their end of life hinges on environmental conditions in which they are disposed of. Their management in anaerobic digestion (AD) remains a topic of debate and needs further investigatation. This study assesses the behaviour of PHBV, a prominent bio-based biodegradable plastic, blended with cellulose fibres in mesophilic AD conditions. Results show that degradation depends on material characteristics such as its specific surface area and cellulose content. Nearly complete biodegradation was observed for 1 mm diameter powder and 67% degradation for 2 x 2 cm films over 57 days of AD at 38°C. Biodegradation is quicker with higher cellulose content up to 40%. Morphological, structural, and functional analyses indicate that biodegradation occurred primarily through surface erosion, resulting in reduced polymers molecular weight and crystallinity, along with shifts in functional ester groups. Specific microbial genera, such as Ruminofilibacter, Thiospeudomonas, and HN.HF0106, were abundant in the planktonic phase, while Ruminofilibacter, Clostridium sensu stricto 7, UCG.012, and Treponema dominated the biofilm during AD. This research aims to provide deeper understanding of PHBV degradation mechanisms in AD, crucial for effective management in such conditions.

Source: The Science of The Total Environment

DOI: 10.1016/j.scitotenv.2024.178224

Authors: Paul Derkenne, Lucile Chatellard, Fabrice Béline, Anne-Catherine Pierson-Wickmann, Nathalie Gontard, Patrick Dabert