title: Selective adsorption of hydrocarbon-oxidizing Rhodococcus cells in a column with hydrophobized poly(acrylamide) cryogel.
abstract: A method for selective adsorption of Rhodococcus cells in the column with hydrophobized poly(acrylamide) cryogel (cryoPAAG) was developed that allowed rhodococci separation from mixed bacterial populations and their effective concentration within a sponge-like gel matrix. Hydrophobization of cryoPAAG using the n-dodecane graft (C12) was performed to enhance the adhesion of Rhodococcus cells to the cryogel; this was suggested by our finding that alkanotrophic rhodococci possess high adhesive activity (91-98%) towards n-alkanes, whereas other Gram-positive and Gram-negative bacteria tested did not adhere strongly to hydrocarbons. The selective index of the hydrophobic C12-cryoPAAG column for Rhodococcus cells was 72% that ensured their separation from complex bacterial cultures. Respirometry results using the Columbus Micro-Oxymax respirometer showed that the maximal respiratory activity of C12-cryoPAAG-immobilized Rhodococcus cells incubated with petroleum hydrocarbons was 1.6-1.8 times higher than that of freely suspended cells, and this correlated with the largest immobilized cell number. Moreover, high respiration rates were maintained over 3 weeks of incubation, indicating a considerable functional stability of the cryoPAAG-immobilized biocatalyst developed.
authors.affiliation: Institute of Ecology and Genetics of Microorganisms, Russian Academy of Sciences, Perm, Russia. kuyukina@iegm.ru
authors.forename: Maria S
authors.initials: MS
authors.lastname: Kuyukina
authors.forename: Ekaterina V
authors.initials: EV
authors.lastname: Rubtsova
authors.forename: Irena B
authors.initials: IB
authors.lastname: Ivshina
authors.forename: Roman V
authors.initials: RV
authors.lastname: Ivanov
authors.forename: Vladimir I
authors.initials: VI
authors.lastname: Lozinsky
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000327:Adsorption; D001431:Bacteriological Techniques / Q000379:methods; D059985:Cryogels; D006838:Hydrocarbons / Q000378:metabolism*; D020100:Hydrogels / Q000737:chemistry*; D010084:Oxidation-Reduction; D012240:Rhodococcus / Q000302:isolation & purification* / Q000378:metabolism*; D000099166:Polyacrylamides
chemical_list: D000180:Acrylic Resins; D059985:Cryogels; D006838:Hydrocarbons; D020100:Hydrogels; D000099166:Polyacrylamides