title: Drotaverine hydrochloride degradation using cyst-like dormant cells of Rhodococcus ruber.
abstract: This work has a focus on adaptive capabilities of the actinobacterium Rhodococcus ruber IEGM 326 to cope with drotaverine hydrochloride (DH), a known pharmaceutical pollutant. Cultivation of R. ruber in a nitrogen-limited medium with incubation at the ambient temperature resulted in the formation of cyst-like dormant cells (CLDCs). They maintained viability for 2-7 months, possessed the undetectable respiratory activity and elevated resistance to heating, and had a specific morphology. CLDCs are regarded to ensure long-term survival in various habitats and may be used as storage formulations. R. ruber IEGM 326 was tolerant to DH (MIC, 200 mg/l) and displayed different abilities to degrade this compound, depending on inoculum, temperature, and the presence of glucose as co-oxidized substrate. Thus, the loss of DH (20 mg/l) over 48 h at the optimal temperature (27 ± 2 °C) was 5-8 % in the absence of glucose after inoculating with vegetative cells. The addition of glucose (5 g/l) increased DH degradation up to 46 %. Noteworthy, CLDCs as inoculum were advantageous over vegetative cells to degrade DH at the non-optimal temperature (35 ± 2 °C) at reduced bulk respiratory activity. The obtained results are promising to improve the biodegrading capabilities of other Rhodococcus strains.
authors.affiliation: Institute of Ecology and Genetics of Microorganisms, Russian Academy of Sciences, 13 Golev Street, 614081, Perm, Russia, ivshina@iegm.ru.
authors.forename: Irena B
authors.initials: IB
authors.lastname: Ivshina
authors.forename: Anna N
authors.initials: AN
authors.lastname: Mukhutdinova
authors.forename: Helena A
authors.initials: HA
authors.lastname: Tyumina
authors.forename: Helena V
authors.initials: HV
authors.lastname: Vikhareva
authors.forename: Nataliya E
authors.initials: NE
authors.lastname: Suzina
authors.forename: Galina I
authors.initials: GI
authors.lastname: El'-Registan
authors.forename: Andrey L
authors.initials: AL
authors.lastname: Mulyukin
mesh_terms: D001673:Biodegradation, Environmental; D003470:Culture Media; D004785:Environmental Pollutants / Q000378:metabolism; D010208:Papaverine / Q000031:analogs & derivatives* / Q000378:metabolism; D012240:Rhodococcus / Q000378:metabolism* / Q000648:ultrastructure; D013696:Temperature
chemical_list: D003470:Culture Media; D004785:Environmental Pollutants; C005317:drotaverin; D010208:Papaverine