title: Bacterial succession and degradative changes by biofilm on plastic medium for wastewater treatment.
abstract: Biofilms contain a diverse range of microorganisms and their varying extracellular polysaccharides. The present study has revealed biofilm succession associated with degradative effects on plastic (polypropylene) and contaminants in sludge. The wet weight of biofilm significantly (p < 0.05) increased; from 0.23 ± 0.01 to 0.44 ± 0.01 g. Similarly, the dry weight of the biofilm increased from 0.02 to 0.05 g. Significant reduction in pathogens (E. coli and feacal coliforms) by MPN technique (>80%) and in chemical parameters (decrease in COD, BOD5 of 73.32 and 69.94%) representing diminution of organic pollutants. Energy dispersive X-ray spectroscopy (EDS) of plastic revealed carbon and oxygen contents, further surface analysis of plastic by scanning electron microscopy (SEM) revealed emergence of profound bacterial growth on the surface. Fourier transform infrared (FTIR) spectroscopy conforms its biotransformation under aerobic conditions after 8 weeks. New peaks developed at the region 1050 and 969 cm(-1) indicating CO and CC bond formation. Thus plastic with 6 weeks old aerobic biofilm (free of pathogens, max. weight, and OD, efficient COD & BOD removal ability) is suggested to be maintained in fixed biofilm reactors for wastewater treatment.
authors.affiliation: Microbiology Research Laboratory, Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan.
authors.forename: Nazia
authors.initials: N
authors.lastname: Khatoon
authors.forename: Iffat
authors.initials: I
authors.lastname: Naz
authors.forename: Muhammad Ishtiaq
authors.initials: MI
authors.lastname: Ali
authors.forename: Naeem
authors.initials: N
authors.lastname: Ali
authors.forename: Asif
authors.initials: A
authors.lastname: Jamal
authors.forename: Abdul
authors.initials: A
authors.lastname: Hameed
authors.forename: Safia
authors.initials: S
authors.lastname: Ahmed
mesh_terms: D001422:Bacterial Adhesion; D018441:Biofilms / Q000254:growth & development*; D002954:Citrobacter / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D004754:Enterobacter / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D007709:Klebsiella / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D059013:Microbial Consortia / Q000502:physiology*; D011126:Polypropylenes / Q000737:chemistry*; D012475:Salmonella / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D012722:Sewage / Q000382:microbiology*; D012760:Shigella / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D018508:Water Purification
chemical_list: D011126:Polypropylenes; D012722:Sewage
keywords: Biofilm; Microbial succession; Plastic; Polypropylene