FAMEs profiles of phenol-degrading Pseudomonas stutzeri introduced into soil

Fatty acid composition during phenol biodegradation by Pseudomonas stutzeri introduced into three sterile soils differed in organic matter content was investigated. It was found that type of soil strongly influenced the rate of phenol removal and survival of bacteria. In soil (MF) with the highest amount of organic matter (37.30%) the complete phenol biodegradation proceeded within 44 days, in soil (WM) with intermediate organic matter content (18%) lasted 68 days, whereas in sandy soil (PF) (2.10% of organic matter) phenol degradation was not observed. In phenol-polluted soil the number of introduced P. stutzeri cells decreased during experiment period from an initial density of 2.5 × 109 CFU/g soil to 1.73 × 105 CFU/g soil and to 9.7 × 103 CFU/g soil in MF and WM samples, respectively. Under phenol exposure changes in FAMEs profiles isolated from soils were detected. The most significant alterations were connected with the occurrence and content of cyclopropane fatty acids. Fatty acid 17:0 cy was detected only in uncontaminated soil whereas 19:0 cy ω8c fatty acid was synthesised by introduced bacteria in phenol amended soils when its concentration decreased significantly. Other noticeable changes included the increase of branched and straight-chain fatty acid contents, resulted in the higher level of fatty acids saturation in bacteria isolated from phenol-polluted soils. Our results show that fatty acid composition and the occurrence of specific fatty acids can be used for monitoring the progress of bioremediation process in phenol-polluted environment.