Lipid hydrolysis by Pseudomonas putida 3SK cultured in organic—aqueous two-phase system

Abstract

The hydrolysis of olive oil using an organic solvent-tolerant strain, Pseudomonas putida 3SK, cultured as a source of lipase, has been studied in an organic—aqueous two-phase system. The strain grew well in the two-phase system and produced extracellular lipase simultaneously. Among the organic solvents tested, isooctane was the most suitable solvent for this purpose. Log P values of solvents used had a correlation with lipolytic activity of the strain. The critical log P value of the organic solvent for growth of P. putida 3SK was about 3 in this system. Straight-chain aliphatic hydrocarbons showed a linear relationship between the degree of hydrolysis and their log P values. The degree of hydrolysis in the two-phase system was influenced by several reaction parameters, such as the volumetric ratio of the two phases, type of culture medium, and substrate (olive oil) concentration in an organic phase. The appropriate volume ratio of the aqueous phase (culture medium) to isooctane was 5 : 2 (v/v). The optimal substrate concentration in isooctane was 9% (w/v) and 12.9% (w/v) in the case of LB and minimal media (aqueous phase), respectively, and olive oil would function as a carbon source as well in the case of minimal medium. In this optimized condition, the degree of hydrolysis was increased to 95%, the balance being utilized as a carbon source. Also, hydrolysis of beef tallow, which is solid at ambient temperature, was found to be feasible in this system.