Elemental sulfur biorecovery from phosphogypsum using oxygen-membrane biofilm reactor: Bioreactor parameters optimization, metagenomic analysis and metabolic prediction of the biofilm activity

Ayoub Bounaga; Anwar Alsanea; Mohammed Danouche; Bruce E Rittmann; Chen Zhou; Rachid Boulif; Youssef Zeroual; Rachid Benhida; Karim Lyamlouli

doi:10.1016/j.biortech.2024.130680

Elemental sulfur biorecovery from phosphogypsum using oxygen-membrane biofilm reactor: Bioreactor parameters optimization, metagenomic analysis and metabolic prediction of the biofilm activity

Bioresour Technol. 2024 Apr 7:400:130680. doi: 10.1016/j.biortech.2024.130680. Online ahead of print.

Authors

Ayoub Bounaga¹, Anwar Alsanea², Mohammed Danouche³, Bruce E Rittmann², Chen Zhou², Rachid Boulif³, Youssef Zeroual⁴, Rachid Benhida⁵, Karim Lyamlouli⁶

Affiliations

¹ Department of Chemical & Biochemical Sciences-Green Process Engineering (CBS), Mohammed VI Polytechnic University, Benguerir 43150, Morocco; Biodesign Swette Center for Environmental Biotechnology, Arizona State University, P.O. Box 875017, Tempe, AZ 85287-5701, USA.
² Biodesign Swette Center for Environmental Biotechnology, Arizona State University, P.O. Box 875017, Tempe, AZ 85287-5701, USA.
³ Department of Chemical & Biochemical Sciences-Green Process Engineering (CBS), Mohammed VI Polytechnic University, Benguerir 43150, Morocco.
⁴ Situation Innovation, OCP Group, BP 118, Jorf Lasfar El Jadida, 24000, Morocco.
⁵ Department of Chemical & Biochemical Sciences-Green Process Engineering (CBS), Mohammed VI Polytechnic University, Benguerir 43150, Morocco; Institute of Chemistry, Nice UMR7272, Côte d'Azur University, French National Centre for Scientific Research (CNRS), Nice, France.
⁶ College of Sustainable Agriculture and Environmental Sciences, Agrobioscience Program, Mohammed VI Polytechnic University, Benguerir 43150, Morocco. Electronic address: Karim.lyamlouli@um6p.ma.

PMID: 38593965
DOI: 10.1016/j.biortech.2024.130680

Abstract

This work investigated elemental sulfur (S⁰) biorecovery from Phosphogypsum (PG) using sulfur-oxidizing bacteria in an O₂-based membrane biofilm reactor (MBfR). The system was first optimized using synthetic sulfide medium (SSM) as influent, then switched to biogenic sulfide medium (BSM) generated by biological reduction of PG alkaline leachate. The results using SSM had high sulfide-oxidation efficiency (98 %), sulfide to S⁰ conversion (∼90 %), and S⁰ production rate up to 2.7 g S⁰/(m².d), when the O₂/S ratio was ∼0.5 g O₂/g S. With the BSM influent, the system maintained high sulfide-to-S⁰ conversion rate (97 %), and S⁰-production rate of 1.6 g S⁰/(m².d). Metagenomic analysis revealed that Thauera was the dominant genus in SSM and BSM biofilms. Furthermore, influent composition affected the bacterial community structure and abundances of functional microbial sulfur genes, modifying the sulfur-transformation pathways in the biofilms. Overall, this work shows promise for O₂-MBfR usage in S⁰ biorecovery from PG-leachate and other sulfidogenic effluents.

Keywords: Elemental sulfur biorecovery; MBfR; Phosphogypsum leachate; Sulfide-oxidizing bacteria; Sulfur-metabolic pathways.