RESUMEN
It is known that isolation of oil-degrading bacterial strains is difficult at low temperatures, and the biodegradation efficiency of oil-contaminated soil is significantly reduced in cold weather. In this study, 14 strains were isolated from oil-contaminated soil that grew well at 10°C by using a newly developed culture method. 11 of the 14 isolates were successfully cultured in mineral salts medium containing 1,500 ppm of oil components, 500 ppm each kerosene, gasoline, and diesel as carbon sources, at 10°C for 2 weeks. The oil degradation efficiencies of these 11 isolates ranged from 36% to 100%, as measured by total petroleum hydrocarbon (TPH) degradation analyses. Three strains (Pseudomonas simiae G1-10O, P. taiwanensis Y1-4, and P. koreensis Gwa2) displayed complete degradation (100%), and six others (R frederiksbergensis G2-2, P arsenicoxydans Y2-1, R umsongensis Gwa3, P. migulae Gwa5, RhodococcusjialingiaeY 1-l , and R. qingshengii Y2-2) showed relatively high degradation efficiencies (> 70%). This study suggests that these isolates can be effectively utilised in thetreatment of oil-contaminated soil in landfarming, especially during winter.
Asunto(s)
Petróleo/metabolismo , Pseudomonas/metabolismo , Rhodococcus/metabolismo , Contaminantes del Suelo/metabolismo , Petróleo/análisis , Pseudomonas/clasificación , Pseudomonas/aislamiento & purificación , República de Corea , Rhodococcus/clasificación , Rhodococcus/aislamiento & purificación , Contaminantes del Suelo/químicaRESUMEN
Strain NHI-24(T) was isolated from forest soil by a polycarbonate membrane transwell plate. It is a Gram-negative, rod-shaped, non-motile, non-spore-forming bacterium. Phylogenetic analysis based on 16S rRNA gene sequence data indicated that strain NHI-24(T) is closely related to members of the genus Niabella: N. drilacis E90(T) (97.7 %), N. tibetensis 15-4(T) (96.7 %), N. aurantiaca R2A15-11(T) (96.5 %), N. hirudinis E96(T) (95.8 %), N. soli JS13-8(T) (94.7 %), N. ginsengisoli NBRC106414(T) (94.4 %), and N. yanshanensis CCBAU 05354(T) (94.2 %). Growth temperatures range widely, from 15 to 37 °C, with 30 °C as the optimum. Salt tolerance ranges from 0 to 2 %. The strain grows at pH 6.5-11.0, with an optimal range of pH 7.0-9.5. Cells produce flexirubin-type pigments, and the predominant menaquinone is MK-7. The major fatty acids of strain NHI-24(T) are iso-C15:0 (36.72 %), iso-C15:1 G (20.8 %), and summed feature 3 (C16:1 ω7c/C16:1 ω6c; 15.2 %). DNA-DNA hybridization values between strain NHI-24(T) and members of the genus Niabella range from 37 to 53 %. Based on these results, it is proposed that strain NHI-24(T) represents a novel species of the genus Niabella with the name Niabella thaonhiensis (= KACC 17215(T) = KEMB 9005-018(T) = JCM 18864(T)).
Asunto(s)
Bacteroidetes/clasificación , Bacteroidetes/aislamiento & purificación , Microbiología del Suelo , Bacteroidetes/genética , Bacteroidetes/fisiología , Análisis por Conglomerados , Citosol/química , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Ácidos Grasos/análisis , Bosques , Concentración de Iones de Hidrógeno , Corea (Geográfico) , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Filogenia , Pigmentos Biológicos , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Temperatura , Universidades , Vitamina K 2/análisisRESUMEN
Despite the abundance of bacterial species in soil, more than 99% of these species cannot be cultured by traditional techniques. In addition, the less than 1% of bacteria that can be cultured are not representative of the total phylogenetic diversity. Hence, identifying novel species and their new functions is still an important task for all microbiologists. Cultivating techniques have played an important role in identifying new species but are still low-throughput processes. This review discusses the issues surrounding cultivation, including achievements, limitations, challenges, and future directions.