Biological treatment of perfluorooctanesulfonic acid (PFOS) using microbial capsules of a polysulfone membrane

Sovannlaksmy Sorn; Hiroe Hara-Yamamura; Sreyla Vet; Minhao Xiao; Eric M V Hoek; Ryo Honda

doi:10.1016/j.chemosphere.2023.138585

Biological treatment of perfluorooctanesulfonic acid (PFOS) using microbial capsules of a polysulfone membrane

Chemosphere. 2023 Jul:329:138585. doi: 10.1016/j.chemosphere.2023.138585. Epub 2023 Apr 5.

Authors

Sovannlaksmy Sorn¹, Hiroe Hara-Yamamura², Sreyla Vet¹, Minhao Xiao³, Eric M V Hoek³, Ryo Honda⁴

Affiliations

¹ Graduate School of Natural Science and Technology, Kanazawa University, Japan.
² Faculty of Geosciences and Civil Engineering, Kanazawa University, Japan.
³ Department of Civil and Environmental Engineering, University of California, Los Angeles, USA.
⁴ Faculty of Geosciences and Civil Engineering, Kanazawa University, Japan; Department of Civil and Environmental Engineering, University of California, Los Angeles, USA. Electronic address: rhonda@se.kanazawa-u.ac.jp.

PMID: 37028728
DOI: 10.1016/j.chemosphere.2023.138585

Abstract

Perfluorooctanesulfonic acid (PFOS) is a persistent organic substance that has been extensively applied in many industries and causes severe, widespread adverse health impacts on humans and the environment. The development of an effective PFOS treatment method with affordable operational costs has been expected. This study proposes the biological treatment of PFOS using microbial capsules enclosing a PFOS-reducing microbial consortium. The objective of this study was to evaluate the performance of the polymeric membrane encapsulation technique for the biological removal of PFOS. First, a PFOS-reducing bacterial consortium, composed of Paracoccus (72%), Hyphomicrobium (24%), and Micromonosporaceae (4%), was enriched from activated sludge by acclimation and subsequent subculturing with PFOS containing media. The bacterial consortium was first immobilized in alginate gel beads, then enclosed in membrane capsules by coating the gel beads with a 5% or 10% polysulfone (PSf) membrane. The introduction of microbial membrane capsules could increase PFOS reduction to between 52% and 74% compared with free cell suspension, which reduced by 14% over three weeks. Microbial capsules coated with 10% PSf membrane demonstrated the highest PFOS reduction at 80% and physical stability for six weeks. Candidate metabolites including perfluorobutanoic acid (PFBA) and 3,3,3- trifluoropropionic acid were detected by FTMS, suggesting the possible biological degradation of PFOS. In microbial membrane capsules, the initial adsorption of PFOS on the shell membrane layer enhanced subsequent biosorption and biological degradation by PFOS-reducing bacteria immobilized in the core alginate gel beads. The 10%-PSf microbial capsules exhibited a thicker membrane layer with the fabric structure of a polymer network, which maintained longer physical stability than 5%-PSf microbial capsules. This outcome suggests the potential application of microbial membrane capsules to PFOS-contaminated water treatment.

Keywords: Alginate gel beads; Bioremediation; Microbial encapsulation; Perfluoroalkhyl substance (PFAS); Polysulfone (PSf).

MeSH terms

Alginates / chemistry
Bacteria
Capsules / chemistry
Humans
Polymers* / chemistry
Sulfones* / chemistry

Substances

polysulfone P 1700
perfluorooctane sulfonic acid
Polymers
Sulfones
Alginates
Capsules