ORIGINAL PAPER Sol–gel silica hybrid biomaterials for application in biodegradation of toxic compounds Georgi Chernev • Nadezhda Rangelova • Petar Djambazki • Sanchi Nenkova • Isabel Salvado • Maria Fernandes • Aiying Wu • Lyudmila Kabaivanova Received: 9 February 2011 / Accepted: 28 February 2011 / Published online: 12 March 2011 Ó Springer Science+Business Media, LLC 2011 Abstract The purpose of the present work is the sol–gel synthesis, structure characterization and potential applica- tion of hybrid biomaterials based on silica precursor (MTES) and natural polymers such as gelatin or pectin. The structure formation in the biomaterials was investi- gated by XRD, FTIR, BET and AFM. The results showed that all studied hybrid biomaterials have an amorphous structure. The FT-IR spectra of the obtained materials with MTES showed chemical bonds at 2,975, 1,255, 880 and 690 cm -1 due to the presence of Si–O–R (CH 3 and C 2 H 5 ) and Si–C bonds. In the samples synthesized with TEOS the inorganic and organic components interact by hydrogen bonding, Van der Waals or electrostatic forces. Surface area of investigated samples decreases with increasing of the natural polymers content. The structure evolution was studied by AFM and roughness analysis. Depending on the chemical composition a different design and size of particles and their aggregates on the surface structure were established. The hybrid biomaterials were used for immo- bilization of bacterial cells and applied in the biodegrada- tion of the toxic compound 4-chlorobutyronitrile, possible constituent of waste water effluents in a laboratory glass bioreactor. Optimization of the process at different tem- peratures was carried out. Keywords Sol–gel  Hybrid biomaterials  Immobilization  Biodegradation 1 Introduction Sol–gel chemistry [1] allows the combination at the nanosize level of inorganic and organic parts in a hybrid composite, providing access to an immense new area of materials science [2–4]. The family of inorganic–organic hybrid materials has attracted considerable attention due to their valuable properties such as: molecular homogeneity, transparency, flexibility and durability [5–8]. The nano- structure, the degree of organization and properties of such materials certainly depend on the chemical nature of their components, but they also rely on the synergy between them [9, 10]. The nature of the interface or the nature of the links and interactions between the organic and inorganic components has been used to categorize these hybrids into two main different classes [11, 12]. Biopolymers like pectin and gelatin are natural macro- molecules which play a prominent role acting as constitu- ents of plant fibers, wood and bones. Pectins are a family of complex polysaccharides that contain 1,4-linked a-D- galacturonic acid residues. Part of the carboxyl groups in pectin macromolecule is methoxylated [13]. Gelatin is a protein derived from collagen which is the major structural G. Chernev (&)  P. Djambazki Department of Silicate Technology, University of Chemical Technology and Metallurgy, 8 Kl. Ohridsky Blvd., 1756 Sofia, Bulgaria e-mail: georgi_chernev@yahoo.com N. Rangelova  S. Nenkova Department of Fundamentals of Chemical Technology, University of Chemical Technology and Metallurgy, 8 Kl. Ohridsky Blvd., 1756 Sofia, Bulgaria I. Salvado  M. Fernandes  A. Wu Department of Ceramic and Glass Engineering, University of Aveiro, CICECO, 3810-193 Aveiro, Portugal L. Kabaivanova Institute of Microbiology, Bulgarian Academy of Science, 26 Acad. G. Bonchev Str., 1113 Sofia, Bulgaria 123 J Sol-Gel Sci Technol (2011) 58:619–624 DOI 10.1007/s10971-011-2436-5