Vol.:(0123456789) 1 3 Chemical Papers https://doi.org/10.1007/s11696-018-0487-6 ORIGINAL PAPER Study of the binding sites in the biomass of Aspergillus niger wild‑type strains by FTIR spectroscopy Katarína Gáplovská 1  · Alexandra Šimonovičová 2  · Radoslav Halko 3  · Lenka Okenicová 3  · Mária Žemberyová 3  · Slavomír Čerňanský 4  · Paula Brandeburová 5  · Tomáš Mackuľak 5 Received: 19 December 2017 / Accepted: 25 April 2018 © Institute of Chemistry, Slovak Academy of Sciences 2018 Abstract Fourier transform infrared (FTIR) spectroscopy studies were performed to confirm and to provide information on the identity and binding characteristics of the chemical groups responsible for the binding of elements using Aspergillus niger (A. niger) wild-type strains. Two absorption bands in the 3690–3615 and 2970–2895 cm −1 regions can characterize stretching vibrations OH and CH groups in fatty acids, respectively, and intensive bands around of 1600 cm −1 and by 1048 cm −1 correspond to stretching vibrations of C=O groups of amides (amide I) or stretching vibrations ν(C–N). The FTIR results confirmed that no extra differences between IR spectra of A. niger in raw biomass and in solid rest after extraction with chloroform were observed. The small differences were observed in IR spectra of A. niger in chloroform after extraction. Keywords Aspergillus niger · Bioaccumulation · Binding sites · FTIR spectroscopy · UV spectroscopy · Elemental analysis Introduction Microscopic filamentous fungi are ubiquitous and wide- spread microorganisms that play an important role in bio- degradation of organic material in the environment. How- ever, living as well as non-living fungal biomass can be used in sorption processes mainly due to unique composition of its cell walls (Gow et al. 2017; Dhankhar and Hooda 2011; Volesky 2003). This structural uniqueness of fungal cell walls differs significantly among various fungal species as well as fungal strains of the same species (Bowman and Free 2006). Thus, fungal metabolism and chemical composition of fungal cells are strongly dependent on the studied fun- gal strain and its original habitat affected by various envi- ronmental factors (Zemberyova et al. 2014; Šimonovičová et al. 2013). Fungal cell walls contain numerous quantities of glycoproteins and polysaccharides, mainly glucan and chitin, which can provide abundant functional groups (e.g., carboxyl, hydroxyl, sulphonate, phosphoryl, amido, amino, and imidazole groups) for metal(loid) binding (Vendruscolo et al. 2017; Horník et al. 2013; Chojnacka 2010). The strong species and strain diversity and differences in chemical com- position of fungal cell walls allow applying fungi in biosorp- tion processes of both cationic and anionic contaminants (Dadval and Mishra 2017; Gola et al. 2017; Rodríguez et al. 2013). Bioprospecting and further application of such different strains of the same species can be very beneficial for their variable uses such as removal of potentially toxic metal(loid) s from wastewaters. Moreover, filamentous fungi are applied in a variety of industrial fermentation processes which can serve as a rich source of biomass for metal(loid) removal. Therefore, fungi can be considered as low-price biosorbent with a high metal(loid)-binding capacity and selectivity for metal(loid)s (Yang et al. 2017; Wang and Chen 2006). * Paula Brandeburová brandeburova.paula@gmail.com 1 Faculty of Natural Sciences, Institute of Chemistry, Comenius University, Mlynská dolina CH-2, Ilkovičova 6, 842 15 Bratislava, Slovakia 2 Department of Soil Science, Faculty of Natural Sciences, Comenius University, Mlynská dolina B-2, Ilkovičova 6, 842 15 Bratislava, Slovakia 3 Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská dolina CH-2, Ilkovičova 6, 842 15 Bratislava, Slovakia 4 Department of Environmental Ecology, Faculty of Natural Sciences, Comenius University, Mlynská dolina B-2, Ilkovičova 6, 842 15 Bratislava, Slovakia 5 Department of Environmental Engineering, Faculty of Chemical and Food Technology, Slovak University of Technology, Bratislava, Slovakia