ENVIRONMENTAL BIOTECHNOLOGY Adaptation mechanisms of bacteria during the degradation of polychlorinated biphenyls in the presence of natural and synthetic terpenes as potential degradation inducers Slavomíra Zorádová-Murínová & Hana Dudášová & Lucia Lukáčová & Milan Čertík & Katarína Šilharová & Branislav Vrana & Katarína Dercová Received: 29 September 2011 /Revised: 13 November 2011 /Accepted: 14 November 2011 /Published online: 10 December 2011 # Springer-Verlag 2011 Abstract In this study, we examined the effect of polychlori- nated biphenyls (PCBs) in the presence of natural and syn- thetic terpenes and biphenyl on biomass production, lipid accumulation, and membrane adaptation mechanisms of two PCB-degrading bacterial strains Pseudomonas stutzeri and Burkholderia xenovorans LB400. According to the results obtained, it could be concluded that natural terpenes, mainly those contained in ivy leaves and pine needles, decreased adaptation responses induced by PCBs in these strains. The adaptation processes under investigation included growth inhibition, lipid accumulation, composition of fatty acids, cis/trans isomerization, and membrane saturation. Growth inhibition effect decreased upon addition of these natural compounds to the medium. The amount of unsaturated fatty acids that can lead to elevated membrane fluidity increased in both strains after the addition of the two natural terpene sources. The cells adaptation changes were more prominent in the presence of carvone, limonene, and biphenyl than in the presence of natural terpenes, as indicated by growth inhibition, lipid accumulation, and cis/trans isomerization. Addition of biphenyl and carvone simultaneously with PCBs increased the trans/cis ratio of fatty acids in mem- brane fractions probably as a result of fluidizing effects of PCBs. This stimulation is more pronounced in the presence of PCBs as a sole carbon source. This suggests that PCBs alone have a stronger effect on bacterial membrane adapta- tion mechanisms than when added together with biphenyl or natural or synthetic terpenes. Keywords Membrane lipids . Polychlorinated biphenyls . Adaptation . Bacteria . Environmental stress . Terpenes . Stimulators Introduction PCBs constitute a class of 209 congeners that are structur- ally related. They comprise a biphenyl core with varying number of chlorine atoms and are produced by catalytic chlorination of biphenyl to various degrees (Furukawa et al. 1978; Arensdorf and Focht 1994;Tříska et al. 2004). PCBs have had a wide range of industrial applications, particularly as lubricants, cooling agents, and electric insu- lants. Between 1930 and 1979, over 600 million kg of PCBs were used in North America alone (Sylvestre 1995). Although the manufacture of PCBs has been forbidden (in USA in 1970; in Slovak Republic in 1984) they still pose an environmental problem due to their presence in electrical transformers, landfills, and contaminated sites in the areas around former production facilities. Their physical and chemical properties such as thermal and chemical stability, resistance to degradation, and general inertness contribute to their persistence in the environment (Tříska et al. 2004). PCBs represent potential health risks for living organisms due to their lipophilic nature, toxicity, and possible carcino- genic properties (Komancová et al. 2003). Studies per- formed with individual PCB congeners show that PCB toxicity is structure-related (Safe 1978). S. Zorádová-Murínová (*) : H. Dudášová : L. Lukáčová : M. Čertík : K. Dercová Institute of Biotechnology and Food Science, Department of Biochemical Technology, Slovak University of Technology, Faculty of Chemical and Food Technology, Radlinského 9, 812 37 Bratislava, Slovakia e-mail: slavomira.murinova@gmail.com K. Šilharová : B. Vrana Water Research Institute, Nábrežie arm. gen. L. Svobodu 5, 812 49 Bratislava, Slovakia Appl Microbiol Biotechnol (2012) 94:1375–1385 DOI 10.1007/s00253-011-3763-8