Polyhydroxyalkanoate Synthesis Affects Biosurfactant Production and Cell Attachment to Hydrocarbons in Pseudomonas sp. KA-08

Abstract

Stressful conditions prevailing in hydrocarbon-contaminated sites influence the diversity, distribution, and activities of microorganisms. Oil bioremediation agents should develop special characteristics to cope with these environments like surfactant production and cellular affinity to hydrocarbons. Additionally, polyhydroxyalkanoate (PHA) accumulation was proven to improve tolerance to stressful conditions. Pseudomonas sp. KA-08 was isolated from a chronic oil-contaminated environment, it is highly tolerant to xylene, and it is able to accumulate PHA and to produce surfactant compounds that lower the water surface tension (ST) as well as bioemulsifiers. In this work, we studied the effect of the capability to accumulate PHAs on biosurfactant production and microbial attachment to hydrocarbons (MATH). Our results showed that PHA synthesis capability has a favorable effect in the production of compounds which affect the ST but not on the production of bioemulsifiers. On the other hand, PHA accumulation affects cellular affinity to xylene. MATH analysis showed that a PHA-negative mutant increased its affinity to xylene compared with the wild-type strain. This result was also observed in Pseudomonas putida GPp104 (a PHA- mutant), suggesting that this effect could be generalized to other Pseudomonas strains.