title: Bacterial community dynamics in a biodenitrification reactor packed with polylactic acid/poly (3-hydroxybutyrate-co-3-hydroxyvalerate) blend as the carbon source and biofilm carrier.
abstract: While heterotrophic denitrification has been widely used for treating such nitrogen-rich wastewater, it requires the use of additional carbon sources. With fluctuations in the nitrate concentration in the influent, controlling the C/N ratio to avoid carbon breakthrough becomes difficult. To overcome this obstacle, solid-phase denitrification (SPD) using biodegradable polymers has been used, where denitrification and carbon source biodegradation depend on microorganisms growing within the reactor. However, the microbial community dynamics in continuous-flow SPD reactors have not been fully elucidated yet. Here, we aimed to study bacterial community dynamics in a biodenitrification reactor packed with a polylactic acid/poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PLA/PHBV) blend as the carbon source and biofilm carrier. A lab-scale denitrifying reactor filled with a PLA/PHBV blend was used. With 85 mg/L of influent NO3-N concentration and a hydraulic retention time (HRT) of 2.5 h, more than 92% of the nitrate was removed. The bacterial community of inoculated activated sludge had the highest species richness in all samples. Bacterial species diversity in the reactor first decreased and then increased to a stable level. Diaphorobacter species were predominant in the reactor after day 24. In total, 178 clones were retrieved from the 16S rRNA gene clone library constructed from the biofilm samples in the reactor at 62 days of operation, and 80.9% of the clones were affiliated with Betaproteobacteria. Of these, 97.2% were classified into phylotypes corresponding to Diaphorobacter nitroreducens strain NA10B with 99% sequence similarity. Diaphorobacter, Rhizobium, Acidovorax, Rubrivivax, Azospira, Thermomonas, and Acidaminobacter constituted the biofilm microflora in the stably running reactor.
authors.affiliation: Beijing Agro-Biotechnology Research Center, Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, PR China.
authors.forename: Tianlei
authors.initials: T
authors.lastname: Qiu
authors.affiliation: Beijing Agro-Biotechnology Research Center, Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, PR China; Jilin Originwater Technology Co., LTD, Changchun 130012, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Beijing Agro-Biotechnology Research Center, Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, PR China.
authors.forename: Min
authors.initials: M
authors.lastname: Gao
authors.affiliation: Beijing Agro-Biotechnology Research Center, Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, PR China.
authors.forename: Meilin
authors.initials: M
authors.lastname: Han
authors.affiliation: Beijing Agro-Biotechnology Research Center, Beijing Key Laboratory of Agricultural Genetic Resources and Biotechnology, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, PR China; Key Laboratory of Urban Agriculture (North), Ministry of Agriculture, Beijing 100097, PR China. Electronic address: wangxuming@baafs.net.cn.
authors.forename: Xuming
authors.initials: X
authors.lastname: Wang
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000378:metabolism* / Q000494:pharmacology; D020562:Betaproteobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D018441:Biofilms / Q000187:drug effects; D019149:Bioreactors / Q000382:microbiology*; D002244:Carbon / Q000378:metabolism* / Q000494:pharmacology; D042621:Comamonadaceae / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D058440:Denitrification; D009566:Nitrates / Q000302:isolation & purification / Q000378:metabolism; D009584:Nitrogen / Q000302:isolation & purification / Q000378:metabolism; D010421:Pentanoic Acids / Q000378:metabolism* / Q000494:pharmacology; D011091:Polyesters / Q000378:metabolism* / Q000494:pharmacology; D011108:Polymers / Q000378:metabolism* / Q000494:pharmacology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000382:microbiology; D062065:Wastewater / Q000737:chemistry; D000094122:Polyhydroxybutyrates
chemical_list: D020155:3-Hydroxybutyric Acid; D002244:Carbon; D009566:Nitrates; D009584:Nitrogen; D010421:Pentanoic Acids; D011091:Polyesters; D011108:Polymers; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D062065:Wastewater; C052620:poly(3-hydroxybutyrate)-co-(3-hydroxyvalerate); D000094122:Polyhydroxybutyrates; C033616:poly(lactide)
keywords: 16S rRNA gene clone library; Bacterial community; Biodenitrification; Denaturing gradient gel electrophoresis; Poly (3-hydroxybutyrate-co-3-hydroxyvalerate)/polylactic acid