title: Distribution and diversity of biosurfactant-producing bacteria in a wastewater treatment plant.
abstract: The distribution and diversity of culturable biosurfactant-producing bacteria were investigated in a wastewater treatment plant (WWTP) using the Shannon and Simpson's indices. Twenty wastewater samples were analysed, and from 667 isolates obtained, 32 were classified as biosurfactant producers as they reduced the surface tension of the culture medium (71.1 mN/m), with the lowest value of 32.1 mN/m observed. Certain isolates also formed stable emulsions with diesel, kerosene and mineral oils. The 16S ribosomal RNA (rRNA) analysis classified the biosurfactant producers into the Aeromonadaceae, Bacillaceae, Enterobacteriaceae, Gordoniaceae and the Pseudomonadaceae families. In addition, numerous isolates carried the surfactin 4'-phosphopantetheinyl transferase (sfp), rhamnosyltransferase subunit B (rhlB) and bacillomycin C (bamC) genes involved in the biosynthesis of surfactin, rhamnolipid and bacillomycin, respectively. While, biosurfactant-producing bacteria were found at all sampling points in the WWTP, the Simpson's diversity (1 - D) and the Shannon-Weaver (H) indices revealed an increase in bacterial diversity in the influent samples (0.8356 and 2.08), followed by the effluent (0.8 and 1.6094) and then the biological trickling filter (0.7901 and 1.6770) samples. Numerous biosurfactant-producing bacteria belonging to diverse genera are thus present throughout a WWTP.
authors: Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa.
authors: Thando
authors: T
authors: Ndlovu
authors: Department of Biomedical Sciences, Faculty of Health and Wellness Sciences, Cape Peninsula University of Technology, PO Box 1906, Bellville, 7535, South Africa.
authors: Sehaam
authors: S
authors: Khan
authors: Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa. wesaal@sun.ac.za.
authors: Wesaal
authors: W
authors: Khan
mesh_terms: D001406:Bacillaceae / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins; D053898:Biosynthetic Pathways; D003470:Culture Media / Q000737:chemistry; D004655:Emulsions; D004755:Enterobacteriaceae / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D006017:Glycolipids / Q000096:biosynthesis; D033601:Gordonia Bacterium / Q000235:genetics / Q000378:metabolism; D058889:Molecular Typing; D011548:Pseudomonadaceae / Q000235:genetics / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013500:Surface Tension; D013501:Surface-Active Agents / Q000032:analysis / Q000378:metabolism*; D017855:Transferases (Other Substituted Phosphate Groups); D062065:Wastewater / Q000382:microbiology*; D014871:Water Microbiology; D018508:Water Purification
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D004655:Emulsions; D006017:Glycolipids; D012336:RNA, Ribosomal, 16S; D013501:Surface-Active Agents; D017855:Transferases (Other Substituted Phosphate Groups); D062065:Wastewater; C082662:phosphopantetheinyl transferase; C418382:rhamnolipid
keywords: Biosurfactant-producing bacteria; Evenness; Shannon’s index; Simpson’s index; Wastewater