Bacterial diversity of biofilms on polyhydroxybutyrate exposed to marine conditions

Ex-situ vs. in-situ tests

authored by: Aniruddha Bhalerao, Urda Dueker, Miriam Weber, Andreas Eich, Christian Lott, Hans Josef Endres, Regina Nogueira
Abstract: Biofilms form on any available surface and, depending on the characteristics of the material and the environmental conditions, biodegradation can take place. We compared the bacterial composition of polyhydroxybutyrate (PHB)-related biofilm communities from marine ex-situ and in-situ tests to assess the differences in diversity and abundance between these two biofilms. This comparison will help to better assess the transferability of tank tests to real-life scenarios. The in-situ tests were set up in the Mediterranean Sea on the Island of Elba, Italy where PHB-tensile bars were lodged in the sediments. This created a water-exposed aerobic and mud-planted anaerobic scenario. The ex-situ tests were modeled after in-situ tests and performed in temperature-controlled tanks. The PHB-related biofilms were harvested after 240 days of exposure along with planktonic bacteria, and particle- and sediment-related biofilm. The bacterial composition was elucidated using 16S rDNA sequencing. Biofilms harvested from the in-situ test were more diverse, less even, and contained more rare species compared to biofilms from the ex-situ test. The PHB-related biofilm was characterized by a higher abundance of the bacterial order Desulfobacterales. The composition of PHB-related biofilm varied significantly between the two tests and between aerobic and anaerobic conditions. The composition of PHB-related biofilm was significantly different from planktonic bacteria, particle, and sediment-related biofilm, showing the influence of PHB on the biofilm composition. Thus, the ex-situ tank test for PHB degradation cannot, in terms of bacterial composition, simulate the in-situ conditions to their full extent.
Organisation(s): Institute of Plastics and Circular Economy
Institute of Sanitary Engineering and Waste Management
External Organisation(s): HYDRA Marine Sciences GmbH
Type: Article
Journal: Science of the Total Environment
ISSN: 0048-9697
Publication date: 20.12.2023
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Environmental Engineering, Environmental Chemistry, Waste Management and Disposal, Pollution
Sustainable Development Goals: SDG 14 - Life Below Water
Electronic version(s): https://doi.org/10.1016/j.scitotenv.2023.167458 (Access: Closed)