title: Production of extracellular polymeric substances (EPS) by Serratia sp.1 using wastewater sludge as raw material and flocculation activity of the EPS produced.
abstract: Growth profile and extracellular polymeric substances (EPS) production of Serratia sp.1 was studied in shake flask fermentation for 72 h using wastewater sludge as raw material. Maximum cell concentration of 6.7 × 10(9) cfu/mL was obtained at 48 h fermentation time. EPS dry weight, flocculation activity and dewaterability of different EPS (tightly bound or TB-EPS, loosely bound or LB-EPS and broth-EPS or B-EPS) were also measured. The highest concentration of LB-EPS (2.45 g/L) and TB-EPS (0.99 g/L) were attained at 48 h of fermentation. Maximum flocculation activity and dewaterability (ΔCST) of TB-EPS (76.4%, 14.5s and 76.5%, 15.5s), LB-EPS (67.8%, 8.1s and 64.7%, 7.6s) and broth EPS (61%, 6.1s and 70.4%, 6.8s) were obtained at 36 and 48 h of growth. Higher flocculation activity and dewaterability were achieved with TB-EPS than with the two other EPS. Characterization of TB-EPS and LB-EPS was done in terms of their protein and carbohydrate content. Protein content was much higher in TB-EPS where as carbohydrate content was only slightly higher in TB-EPS than LB-EPS. Morphology of the Serratia strain after fermentation in sludge and TSB was observed under a scanning electron microscope and the cell size was found to be bigger in the sludge medium than the TSB medium.
authors.affiliation: INRS-ETE, Université du Québec, 490, Rue de la Couronne, Québec G1K 9A9, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Bezawada
authors.forename: N V
authors.initials: NV
authors.lastname: Hoang
authors.forename: T T
authors.initials: TT
authors.lastname: More
authors.forename: S
authors.initials: S
authors.lastname: Yan
authors.forename: N
authors.initials: N
authors.lastname: Tyagi
authors.forename: R D
authors.initials: RD
authors.lastname: Tyagi
authors.forename: R Y
authors.initials: RY
authors.lastname: Surampalli
mesh_terms: D002241:Carbohydrates / Q000032:analysis*; D005110:Extracellular Space / Q000737:chemistry / Q000378:metabolism*; D005285:Fermentation; D005427:Flocculation; D007616:Kaolin; D011506:Proteins / Q000032:analysis / Q000378:metabolism*; D012705:Serratia / Q000254:growth & development / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*; D062065:Wastewater
chemical_list: D002241:Carbohydrates; D007616:Kaolin; D011506:Proteins; D012722:Sewage; D062065:Wastewater
keywords: CST; EPS production; Fermentation; Flocculation activity; Serratia growth profile; Wastewater sludge