title: Biodegradation of dichloromethane by the polyvinyl alcohol-immobilized methylotrophic bacterium Ralstonia metallidurans PD11.
abstract: A dichloromethane (DCM)-degrading bacterium, Ralstonia metallidurans PD11 NBRC 101272, was immobilized in a polyvinyl alcohol (PVA) gel to use in a bioreactor for DCM treatment. After 4-month incubation of PVA gel beads with R. metallidurans PD11 and DCM in a mineral salt medium, the cells were tightly packed in the mesh of the gel. Forty beads of the gel in 10 ml of a batch system model showed effective activity degrading 500 and 1,000 mg l(-1) DCM within 2 and 3 h, respectively. Although reduction of pH due to accumulation of chloride ion liberated from DCM decreased the activity, it was recovered by adjustment to neutral pH. The activity of the immobilized cells was not affected by addition of nutrients which were preferentially utilized by R. metallidurans PD11, unlike the activity of the free-living cells. A continuous flow system with a column was more effective for rapid degradation of DCM. Thus, the PVA gel-immobilized cell of R. metallidurans PD11 is thought to be a prospective candidate to develop the bioreactor.
authors.affiliation: Graduate School of Natural Science and Technology, Okayama University, Tsushima, Okayama 700-0850, Japan. chi930@pharm.okayama-u.ac.jp
authors.forename: Chizuko
authors.initials: C
authors.lastname: Miyake-Nakayama
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Ikatsu
authors.forename: Minoru
authors.initials: M
authors.lastname: Kashihara
authors.forename: Masako
authors.initials: M
authors.lastname: Tanaka
authors.forename: Michiko
authors.initials: M
authors.lastname: Arita
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Miyoshi
authors.forename: Sumio
authors.initials: S
authors.lastname: Shinoda
mesh_terms: D001673:Biodegradation, Environmental; D018914:Cells, Immobilized / Q000378:metabolism*; D008752:Methylene Chloride / Q000378:metabolism*; D011142:Polyvinyl Alcohol / Q000737:chemistry*; D043367:Ralstonia / Q000145:classification / Q000378:metabolism* / Q000648:ultrastructure; D013997:Time Factors
chemical_list: D008752:Methylene Chloride; D011142:Polyvinyl Alcohol