Application of laser-induced breakdown spectroscopy to the analysis of algal biomass for industrial biotechnology P. Pořízka a , D. Prochazka a , Z. Pilát b , L. Krajcarová c , J. Kaiser a, ⁎, R. Malina a , J. Novotný a , P. Zemánek b , J. Ježek b , M. Šerý b , S. Bernatová b , V. Krzyžánek b , K. Dobranská b , K. Novotný c , M. Trtílek d , O. Samek b a X-ray micro CT and nano CT research group, CEITEC—Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, 616 00 Brno, Czech Republic b Institute of Scientiﬁc Instruments of the ASCR v.v.i., Academy of Sciences of the Czech Republic, Královopolská 147, Brno 61669, Czech Republic c Department of Chemistry, Faculty of Sciences, Masaryk University, Kotlářská 2, Brno 611 37, Czech Republic d Photon Systems Instruments, Drásov 470, 664 24 Drásov, Czech Republic abstract article info Article history: Received 15 December 2011 Accepted 18 June 2012 Available online 26 June 2012 Keywords: LIBS Double-pulse Water-jet Algal biomass Biotechnology We report on the application of laser-induced breakdown spectroscopy (LIBS) to the determination of ele- ments distinctive in terms of their biological signiﬁcance (such as potassium, magnesium, calcium, and sodi- um) and to the monitoring of accumulation of potentially toxic heavy metal ions in living microorganisms (algae), in order to trace e.g. the inﬂuence of environmental exposure and other cultivation and biological factors having an impact on them. Algae cells were suspended in liquid media or presented in a form of ad- herent cell mass on a surface (bioﬁlm) and, consequently, characterized using their spectra. In our feasibility study we used three different experimental arrangements employing double-pulse LIBS technique in order to improve on analytical selectivity and sensitivity for potential industrial biotechnology applications, e.g. for monitoring of mass production of commercial biofuels, utilization in the food industry and control of the re- moval of heavy metal ions from industrial waste waters. © 2012 Elsevier B.V. All rights reserved. 1. Introduction One of the most promising alternatives to satisfy the increasing demands of the human population for energy sources is the produc- tion of carbon-based fuels from plants. By the process of photosyn- thesis plants convert the energy of solar radiation into the chemical energy stored in the molecular building blocks of life (proteins, lipids, carbohydrates, etc.), thus providing energy for most of the life forms on Earth. Moreover, photosynthesis has a crucial impact on Earth's at- mosphere as it generates oxygen while simultaneously using up car- bon dioxide, a prominent greenhouse-effect gas responsible for global climate changes. In order to utilize photoautotrophic microorganisms (algae) for ef- ﬁcient biofuel, food industry, and bioremediation applications [1,2] the optimal cultivation parameters have to be determined for each given purpose, which results in a high production of oil in the selected cell line, increased production of carotenoids/omega-3 oils and poten- tial absorption of heavy-metals in the selected cell line, respectively. This can be accomplished using small-scale photobioreactors that allow precise monitoring and control of the culture irradiance, tem- perature, pH, and gas composition in the medium. However, the abil- ity to monitor the elemental composition of cells and consequently the cellular response to external stimuli in real time (ratios/elemental compositions of algal cells might be signiﬁcantly changed over short periods of time) is not provided. For this purpose qualitative/quantita- tive information about elemental composition of the algal cells that provides a deeper insight into the cellular physiology and enables more efﬁcient optimization of the selected parameters for speciﬁed purposes outlined above is required. So far, only a few studies [3–6] have been performed – using dedicated chemical techniques for lipid determination – to analyze the effect of nutrient elements on oil production/bioremediation. Thus, a fast and remote technique which is capable to analyze elements in-situ within algal cells would be of an advantage. The technique of laser-induced breakdown spectroscopy (LIBS) utilizes the high power densities employing focused radiation from a pulsed, ﬁxed-frequency laser in order to generate luminous plasma from a sample (solid, liquid, and gaseous samples) [7]. In our experi- ments we assume the stoichiometric ablation so that the plasma com- position reﬂects the elemental composition of the ablated target. Here we report on the application of a double-pulse LIBS tech- nique to the analysis of important elements including heavy metal ions in algal cells. The technique of double-pulse LIBS [8] was intro- duced by K. Niemax and his co-workers from ISAS Dortmund in 1991 [9], and nowadays it is a common technique used in many LIBS research laboratories. LIBS has been previously applied to the analysis of biological samples [7,10–12], namely to the determination of Sr in algal pellets [13]. Spectrochimica Acta Part B 74–75 (2012) 169–176 ⁎ Corresponding author. E-mail address: kaiser@fme.vutbr.cz (J. Kaiser). 0584-8547/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.sab.2012.06.014 Contents lists available at SciVerse ScienceDirect Spectrochimica Acta Part B journal homepage: www.elsevier.com/locate/sab