title: The effect of continuous Ni(II) exposure on the organic degradation and soluble microbial product (SMP) formation in two-phase anaerobic reactor.
abstract: A two-phase anaerobic reactor fed with glucose substrate (3 g chemical oxygen demand (COD)/L) was used to investigate the effects of toxic metals on the degradation of organics and the soluble microbial product (SMP) formation. Low concentrations of Ni(II) (5 and 10 mg/L) promoted the acid phase, whereas high concentrations (15, 20, and 25 mg/L) exhibited an inhibitory effect on, but did not alter the fermentative method, which mainly involved the fermentation of propionic acid. The methanogenic microorganism exhibited a strong capability adapting constantly increased Ni(II) levels. The acid phase was an accumulation stage of SMP. In the absence of Ni(II), the high-molecular-weight material in the effluent SMP mainly contained polysaccharide, tryptophan, and casein. Methanogens metabolized most of the polysaccharide, the whole tryptophan content, and part of the casein, leading to the presence of humic acid and protein in effluent. After Ni(II) dosage, the protein and polysaccharide of the acid phase increased, and tryptophan changed, while casein remained stable. More protein than polysaccharide was produced, suggesting the prominent function of protein when addressing the negative effect of toxic metals. The analysis of DNA confirmed the change of bacterial activity.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, China; Jiangsu Key Lab of Environmental Engineering, Jiangsu Provincial Academy of Environmental Science, Nanjing 210036, China. Electronic address: hkywuwei@126.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Wu
authors.affiliation: School of Energy and Environment, Southeast University, Nanjing 210096, China.
authors.forename: Tengteng
authors.initials: T
authors.lastname: Duan
authors.affiliation: School of Energy and Environment, Southeast University, Nanjing 210096, China.
authors.forename: Hailiang
authors.initials: H
authors.lastname: Song
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Jiangsu Key Lab of Environmental Engineering, Jiangsu Provincial Academy of Environmental Science, Nanjing 210036, China.
authors.forename: Ang
authors.initials: A
authors.lastname: Yu
authors.affiliation: Jiangsu Key Lab of Environmental Engineering, Jiangsu Provincial Academy of Environmental Science, Nanjing 210036, China.
authors.forename: Long
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, China. Electronic address: liaimin@nju.edu.cn.
authors.forename: Aimin
authors.initials: A
authors.lastname: Li
mesh_terms: D000693:Anaerobiosis; D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019149:Bioreactors; D009532:Nickel / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical
chemical_list: D014874:Water Pollutants, Chemical; D009532:Nickel
keywords: Ni(II); Soluble microbial products (SMP); Two-phase anaerobic reactor; Upflow anaerobic sludge bed (UASB)