Circular biofilm engineering: Ecological MBBRs using selected microalgae–fungal consortia for sustainable treatment of fish processing wastewater

Title : Circular biofilm engineering: Ecological MBBRs using selected microalgae–fungal consortia for sustainable treatment of fish processing wastewater

Abstract:

The seafood processing industry generates wastewater heavily loaded with organic matter, nitrogen and phosphorus, making its treatment a major challenge for protecting aquatic ecosystems and promoting the circular bioeconomy. This study proposes an ecological biofilm engineering approach based on a Moving Bed Biofilm Reactor (MBBR) using natural biofilm carriers and microbial consortia selected according to the target pollutants to be removed.

Wastewater collected from a seafood processing facility in the Greater Casablanca region was characterised and treated using a consortium composed of selected microalgae, Aspergillus niger, Enterococcus faecium, Saccharomyces cerevisiae and indigenous microorganisms. Sardine scales and shell-derived materials were evaluated as ecological alternatives to conventional synthetic carriers for biofilm development. Reactor performance was assessed by monitoring the removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD?), total nitrogen, phosphorus, nitrate, nitrite, total suspended solids and selected heavy metals. Principal Component Analysis (PCA) was performed to identify the optimal carrier–consortium combinations.

The ecological MBBR achieved more than 90% removal of COD and BOD? within 24 hours, while nitrogen and phosphorus removal progressively improved with increasing hydraulic retention time. The selected microalgae–fungal consortium enhanced biofilm formation, process stability and nutrient recovery, whereas the ecological carriers promoted efficient microbial colonisation.

This study introduces the concept of target-oriented ecological biofilm engineering, in which microbial consortia and biofilm carriers are rationally selected according to the dominant pollutants present in seafood processing wastewater. This strategy offers an innovative, sustainable and adaptable platform for advanced wastewater treatment, resource recovery and circular bioeconomy applications within the aquaculture and seafood processing sectors.

Biography:

Dr Nadia Boutaleb is Professor of Biotechnology and Environmental Engineering at the Faculty of Sciences and Techniques, Hassan II University of Casablanca, Morocco. Her research focuses on environmental biotechnology, biofilm engineering, wastewater treatment, microalgae, fungal biotechnology, microbial ecology and the valorisation of biological resources. She has authored numerous peer-reviewed publications and actively supervises research on sustainable bioprocesses for water treatment and circular bioeconomy. Her current work explores ecological biofilm reactors using selected microbial consortia and natural carrier materials for the treatment and valorisation of industrial and aquaculture effluents.