Biodegradation of diesel/biodiesel blends in saturated sand microcosms Piotr Lisiecki a , Lukasz Chrzanowski a,⇑ , Alicja Szulc a , Lukasz Lawniczak a , Wojciech Białas b , Mariusz Dziadas c , Mikołaj Owsianiak d , Jacek Staniewski a , Paweł Cyplik b , Roman Marecik b , Henryk Jelen ´ c , Hermann J. Heipieper e a Institute of Chemical Technology and Engineering, Poznan University of Technology, Pl. M. Skłodowskiej-Curie 2, 60-965 Poznan ´, Poland b Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, Wojska Polskiego 48, 60-627 Poznan ´, Poland c Institute of Food Technology of Plant Origin, Poznan University of Life Sciences, Wojska Polskiego 31, 60-624 Poznan ´, Poland d Division for Quantitative Sustainability Assessment, Department of Management Engineering, Technical University of Denmark, Produktionstorvet, Building 426, DK-2800 Kgs. Lyngby, Denmark e Helmholtz Centre for Environmental Research – UFZ, Department of Environmental Biotechnology, Permoserstraße 15, D-04318 Leipzig, Germany highlights  Biodegradation of diesel/biodiesel blends was studied for 578 days.  Procedure for monitoring the aliphatic and aromatic fractions was developed.  Additive effect of biodiesel on mineralization of fuel blends was confirmed.  Biodiesel did not impact the biodegradation of aliphatic and aromatic fractions.  Biodiesel can affect the growth of microbial consortium members. article info Article history: Received 4 April 2013 Received in revised form 26 June 2013 Accepted 5 August 2013 Available online 20 August 2013 Keywords: Biodegradation Biodiesel Diesel fuel Hydrocarbon fractions Community dynamics abstract The aim of the study was to evaluate the biodegradation extent of both aromatic and aliphatic hydrocar- bon fractions in saturated sandy microcosm spiked with diesel/biodiesel blends (D, B10, B20, B30, B40, B50, B60, B70, B80, B90 and B100, where D is commercial petroleum diesel fuel and B is commercial biodiesel blend) augmented with a bacterial consortium of petroleum degraders. The biodegradation kinetics for blends were evaluated based on measuring the amount of emitted CO 2 after 578 days. Sub- sequently, the residual aromatic and aliphatic fractions were separated and determined by employing GC-FID and GC  GC–TOF-MS. Additionally, the influence of biodiesel-amendment on the community dynamics was assessed based on the results of real-time PCR analyzes. Our results suggest that the bio- degradation extents of both aliphatic and aromatic hydrocarbon were uninfluenced by the addition of biodiesel, regardless of the concentration used. This observation leads to the conclusion that blending with biodiesel does not impact the long-term biodegradation of specific diesel oil fractions. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Biodegradation is a major removal process of petroleum hydro- carbons in the environment, with degradation half-lives ranging from days to weeks, depending on the type of hydrocarbon and the environmental compartment [1]. Both biodegradation rates and extent of hydrocarbon mixtures containing biodiesel in form of fatty acid methyl esters (FAME), such as diesel/biodiesel blends, are usually higher compared to those of non-blended petroleum fuels [2]. Accelerated biodegradation of fuels containing biodiesel can be attributed to the fact that FAME are a better carbon source compared to petroleum hydrocarbons to support microbial growth [3]. Prince et al. [4] have demonstrated that FAME in a B20 blend (containing 20% v/v of FAME) were degraded at about the same rates as n-alkanes, but at lower rates than other petroleum hydro- carbons by unacclimated freshwater inocula. Little is known about the role of biodiesel in long-term biodeg- radation of petroleum hydrocarbons. DeMello et al. [5] have shown that biodegradation of aliphatic hydrocarbons in the presence of biodiesel (B8 and B25) in seawater microcosms was accelerated at time scales of days, but no effects on compositions of the resid- ual post-biodegradation mixture were observed after 53 days. Cyp- lik et al. [6] speculated that due to structural similarities between FAME and intermediate metabolites of alkane biotransformation, the presence of biodiesel could stimulate the growth of alkane- degraders in aqueous media, but the fate of specific hydrocarbons was not investigated. In porous media, biodiesel can mobilize aged, 0016-2361/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.fuel.2013.08.009 ⇑ Corresponding author. Tel.: +48 61 6653716; fax: +48 61 6653649. E-mail address: lucaschrz@gmx.de (L. Chrzanowski). Fuel 116 (2014) 321–327 Contents lists available at ScienceDirect Fuel journal homepage: www.elsevier.com/locate/fuel