Isolation and functional characterization of hydrocarbon emulsifying and solubilizing factors produced by a Pseudomonas species

Pseudomonas PG‐1 cultivated on pristane produced in good amount a heat‐stable polymeric substance which showed strong hydrocarbon emulsifying and solubilizing properties. The substance was isolated in crude form and was found to contain 34% protein, 16% carbohydrate, and 40% lipid. The hydrocarbon solubilizing activity of the isolate was strongly inhibited by EDTA but the chelating agent had no effect on the hydrocarbon emulsifying activity. Both activities of the isolate were strongly inhibited by chymotrypsin treatment indicating the importance of the protein moiety for its activity. Hydrocarbon solubilization by the isolate showed a certain degree of specificity to pristane in modest agitation generally used in microbial cultivation, but this specificity was lost by vigorous agitation in a Waring blender. It was proposed that in the first case, solubilization was effected by a solubilizing factor specific to pristane, whereas in the latter case, nonspecific solubilization occurred due to the action of the emulsifying factor. The rate of pristane solubilization by heat‐treated culture broth under the conditions of agitation used in cultivation (rotary shaker, 120 rpm) was found to be ca. 750 mg L−1 h−1 which was much larger than the maximal pristane uptake rate of 170 mg L−1 h−1 observed during microbial growth on the substrate. It was concluded that hydrocarbon solubilization could satisfactorily account for the substrate uptake and growth.

[1]  E. Rosenberg,et al.  Emulsifier of Arthrobacter RAG-1: specificity of hydrocarbon substrate , 1979, Applied and environmental microbiology.

[2]  J. N. Baruah,et al.  Characterization of hydrocarbon emulsification and solubilization occurring during the growth of Endomycopsis lipolytica on hydrocarbons , 1979 .

[3]  J. Zajic,et al.  Emulsifying and surface active agents from Corynebacterium hydrocarboclastus , 1977, Biotechnology and bioengineering.

[4]  H. Ohsawa,et al.  Emulsifying Factor of Hydrocarbon Produced by a Hydrocarbon-Assimilating Yeast , 1969 .

[5]  Takeo Suzuki,et al.  Trehalose Lipid and α-Branched-β-hydroxy Fatty Acid Formed by Bacteria Grown on n -Alkanes , 1969 .

[6]  O. Käppeli,et al.  Partition of alkane by an extracellular vesicle derived from hexadecane-grown Acinetobacter , 1979, Journal of bacteriology.

[7]  O. H. Lowry,et al.  Protein measurement with the Folin phenol reagent. , 1951, The Journal of biological chemistry.

[8]  P. L. Kirk,et al.  The ultramicrodetermination of glycogen in liver; a comparison of the anthrone and reducing-sugar methods. , 1953, Archives of biochemistry and biophysics.

[9]  E. Rosenberg,et al.  Emulsifier of Arthrobacter RAG-1: Chemical and Physical Properties , 1979, Applied and environmental microbiology.

[10]  J. N. Baruah,et al.  Predominant role of hydrocarbon solubilization in the microbial uptake of hydrocarbons , 1982, Biotechnology and bioengineering.

[11]  Koichi Yamada,et al.  Protein-like Activator for n-Alkane Oxidation by Pseudomonas aeruginosa S7B1 , 1972 .

[12]  V. Wray,et al.  Formation, Isolation and Characterization of Trehalose Dimycolates from Rhodococcus erythropolis Grown on n-Alkanes , 1979 .

[13]  O. Käppeli,et al.  Characteristics of hexadecane partition by the growth medium of Acinetobacter sp. , 1980 .

[14]  E. Rosenberg,et al.  Emulsifier of Arthrobacter RAG-1: isolation and emulsifying properties , 1979, Applied and environmental microbiology.

[15]  Koichi Yamada,et al.  Formation of Rhamnolipid by Pseudomonas aeruginosa and its Function in Hydrocarbon Fermentation , 1971 .

[16]  D. Cooper,et al.  Production of surface-active lipids by Corynebacterium lepus , 1979, Applied and environmental microbiology.