title: Effect of multiwalled carbon nanotubes on UASB microbial consortium.
abstract: The continuous rise in production and applications of carbon nanotubes (CNTs) has grown a concern about their fate and toxicity in the environment. After use, these nanomaterials pass through sewage and accumulate in wastewater treatment plants. Since, such plants rely on biological degradation of wastes; their activity may decrease due to the presence of CNTs. This study investigated the effect of multiwalled carbon nanotubes (MWCNTs) on upflow anaerobic sludge blanket (UASB) microbial activity. The toxic effect on microbial viability, extracellular polymeric substances (EPS), volatile fatty acids (VFA), and biogas generation was determined. The reduction in a colony-forming unit (CFU) was 29 and 58 % in 1 and 100 mg/L test samples, respectively, as compared to control. The volatile fatty acids and biogas production was also found reduced. The scanning electron microscopy (SEM) and fluorescent microscopy images confirmed that the MWCNT mediated microbial cell damage. This damage caused the increase in EPS carbohydrate, protein, and DNA concentration. Fourier transform infrared (FTIR) spectroscopy results supported the alterations in sludge EPS due to MWCNT. Our observations offer a new insight to understand the nanotoxic effect of MWCNTs on UASB microflora in a complex environment system.
authors.affiliation: Chemical Engineering Department, Sardar Vallabhbhai National Institute of Technology, Ichchhanath, Surat, 395007, Gujarat, India.
authors.forename: Tushar
authors.initials: T
authors.lastname: Yadav
authors.affiliation: Chemical Engineering Department, Sardar Vallabhbhai National Institute of Technology, Ichchhanath, Surat, 395007, Gujarat, India.
authors.forename: Alka A
authors.initials: AA
authors.lastname: Mungray
authors.affiliation: Chemical Engineering Department, Sardar Vallabhbhai National Institute of Technology, Ichchhanath, Surat, 395007, Gujarat, India. akm@ched.svnit.ac.in.
authors.forename: Arvind K
authors.initials: AK
authors.lastname: Mungray
mesh_terms: D000693:Anaerobiosis; D056804:Biofuels / Q000032:analysis; D001704:Biopolymers / Q000032:analysis; D019149:Bioreactors / Q000382:microbiology; D059013:Microbial Consortia / Q000187:drug effects*; D008855:Microscopy, Electron, Scanning; D037742:Nanotubes, Carbon / Q000737:chemistry / Q000633:toxicity*; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity*; D018508:Water Purification / Q000379:methods*
chemical_list: D056804:Biofuels; D001704:Biopolymers; D037742:Nanotubes, Carbon; D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Extracellular polymeric substances (EPS); Multiwalled carbon nanotubes; Nanotoxicity; UASB sludge; Volatile fatty acids (VFA)
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