title: Hydrocarbon degradation and bioemulsifier production by thermophilic Geobacillus pallidus strains.
abstract: Geobacillus pallidus XS2 and XS3 were isolated from oil contaminated soil samples in Yumen oilfield, China, and were able to produce bioemulsifiers on different hydrocarbons. Biodegradation assays exhibited that approximately 70% of PAH (250 mg/L) or 85% of crude oil (500 mg/L) was removed by the thermophilic bacteria after 20 days. The bioemulsifiers of the two strains were isolated and obtained a productive yield of 4.24±0.08 and 3.82±0.11g/L, respectively. GPC analysis revealed that the number-average molecular weights (M(n)) of the two bioemulsifiers were 271,785 Da and 526,369 Da, with PDI values of 1.104 and 1.027, respectively. Chemical composition studies exhibited that the bioemulsifier XS2 consisted of carbohydrates (68.6%), lipids (22.7%) and proteins (8.7%) while the bioemulsifier XS3 was composed by carbohydrates (41.1%), lipids (47.6%) and proteins (11.3%). Emulsification assays approved the effectiveness of bioemulsifiers over a wide range of temperature, pH and salinity.
authors.affiliation: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China. cg1982.zheng@gmail.com
authors.forename: Chenggang
authors.initials: C
authors.lastname: Zheng
authors.forename: Jianglin
authors.initials: J
authors.lastname: He
authors.forename: Yongli
authors.initials: Y
authors.lastname: Wang
authors.forename: Manman
authors.initials: M
authors.lastname: Wang
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Huang
mesh_terms: D001673:Biodegradation, Environmental; D002681:China; D002849:Chromatography, Gas; D016000:Cluster Analysis; D045703:Emulsifying Agents / Q000737:chemistry / Q000302:isolation & purification*; D056506:Geobacillus / Q000235:genetics / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D010578:Petroleum / Q000378:metabolism*; D010802:Phylogeny; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D054712:Salinity; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D013696:Temperature
chemical_list: D045703:Emulsifying Agents; D010578:Petroleum; D011084:Polycyclic Aromatic Hydrocarbons; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants