A coupled UV photolysis-biodegradation process for the treatment of decabrominated diphenyl ethers in an aerobic novel bioslurry reactor

Abstract

The commercial flame retardant is an emerging contaminant (EC) commonly found in soils and sediments. A coupled UVphotolysis-biodegradation process was used to decompose decabromodiphenyl ether (BDE-209) in clay slurries. A novel bioslurry bioreactor (NBB) was employed in which BDE-209 degradation was maximized by the simultaneous application of LED UVA irradiation and biodegradation by a mixed bacterial culture. The rate of BDE-209 degradation decreased in the order: coupled UV photolysis-biodegradation (1.31 × 10-2 day-1) > UV photolysis alone (1.10 × 10-2 day-1) > biodegradation alone (1.00 × 10-2 day-1). Degradation intermediates detected included hydroxylated polybrominated diphenylethers, partially debrominated PBDE congeners and polybrominated dibenzofuran. The UV-resistant bacterial strains isolated that could utilize BDE-209 as a sole carbon source included Stenotrophomonas sp., Pseudomonas sp., and Microbacterium sp. These strains encoded important functional genes such as dioxygenase and reductive dehalogenases. Continuous UV irradiation during the NBB process affected various biochemical oxidative reactions during PBDEs biodegradation. Simultaneous photolysis and biodegradation in the NBB system described reduces operational time, energy, expense, and maintenance-demands required for the remediation of BDE-209 when compared to sequential UV-biodegradation process or to biodegradation alone. Keywords Coupled UV photolysis-biodegradation. Decabromodiphenyl ether. Novel bioslurry bioreactor. UV-resistant bacterial strains. Polybrominated dibenzofuran Highlights • A time, energy, and cost-saving technique using a coupled UV photolysis-biodegradation process for degrading BDE-209 in a novel bioslurry bioreactor. • Identification of isolated UV-resistant bacterial strains that potentially are able to utilize PBDEs as sole carbon source and the analysis of related functional genes. • The prediction of a possible pathway for BDE-209 degradation by coupled photolysis-biodegradation.

The influence of probiotic fermentation on the active compounds and bioactivities of walnut flowers

“…Polyphenolic and flavonoid compounds have well‐known beneficial properties to human health, such as α‐glucosidase inhibition, antioxidant activities, and anti‐inflammatory activity (Im et al., 2016; Kashchenko & Olennikov, 2020), which is mainly attributed to their chemical structures containing multiple hydroxyl substituents on an aromatic ring (Dulic et al., 2019). It is reported that microbial biodegradation may lead to the cleavage and hydroxylation of the aromatic ring (Chang et al., 2021), and some microorganisms could use substrates containing aromatic rings as nutrients (Ni et al., 2013; Vera‐Cabrera et al., 2013).…”

The anti-inflammatory activity of GABA-enriched Moringa oleifera leaves produced by fermentation with Lactobacillus plantarum LK-1

“…The content changes of flavonoids and polyphenols during fermentation may be due to their continuous degradation, convertation, and synthesis during the growth and metabolic processes of microorganisms ( 36 ). For instance, it is reported that microbial degradation may cause the cleavage and hydroxylation of the aromatic ring in flavonoids and polyphenols ( 37 ). Their precipitation or oxidation during the fermentation process may also lead to decrease of these compounds ( 38 ).…”

Degradation of Decabromodiphenyl Ether in an Aerobic Clay Slurry Microcosm Using a Novel Immobilization Technique

“…The first-order rate constants (k) for BDE-209 degradation containing TiO 2 -Yi-Li immobilized chitosan beads in the present study decreased in the order TiO 2 -Yi-Li immobilized chitosan beads (k = 0.166, 1/day) > Yi-Li immobilized chitosan beads (k = 0.132, 1/day). Previously, the rates of BDE-209 degradation in a clay slurry system have been ranked for an aerobic novel bioslurry reactor in the order: coupled UV photolysis-biodegradation (k = 0.0131, 1/day) > UV photolysis alone (k = 0.011, 1/day) > biodegradation alone (k = 0.01, 1/day) [10]. The slowest rate constant for BDE-209 degradation was found to be 0.0054 1/day when the Yi-Li bacterial-mixed culture was added, and the degradation carried out in the dark [23].…”

“…and Stenotrophomonas spp., have the ability to biodegrade PBDEs [6][7][8]. However, microbial bioremediation requires a longer treatment time compared with chemical oxidation remediation or a modified bioremediation process [9,10]. To improve the efficiency of PBDEs biodegradation, one possibility is to combine various eco-friendly physical/chemical/biological processes [10][11][12].…”