In this review, chemical and biological parameters are discussed thatstrongly influence the speciation of heavy metals, their availability tobiological systems and, consequently, the possibilities to usebioremediation as a cleanup tool for heavy metal polluted sites. In orderto assess heavy metal availability, a need exists for rapid, cost-effectivesystems that reliably predict this parameter and, based on this, thefeasibility of using biological remediation techniques for site managementand restoration. Special attention is paid to phytoremediation as anemerging technology for stabilization and remediation of heavy metalpollution. In order to improve phytoremediation of heavy metal pollutedsites, several important points relevant to the process have to beelucidated. These include the speciation and bioavailability of the heavymetals in the soil determined by many chemical and biological parameters, the role of plant-associated soil microorganisms and fungi inphytoremediation, and the plants. Several options are described how plant-associated soil microorganisms canbe used to improve heavy metal phytoremediation.

To demonstrate the importance of sample preparation used in Fourier transform infrared (FTIR) spectroscopy of microbiological materials, bacterial biomass samples with and without grinding and after different drying periods (1.5–23 h at 45 °C), as well as biogenic selenium nanoparticles (SeNPs; without washing and after one to three washing steps) were comparatively studied by transmission FTIR spectroscopy. For preparing bacterial biomass samples, Azospirillum brasilense Sp7 and A. baldaniorum Sp245 (earlier known as A. brasilense Sp245) were used. The SeNPs were obtained using A. brasilense Sp7 incubated with selenite. Grinding of the biomass samples was shown to result in slight downshifting of the bands related to cellular poly-3-hydroxybutyrate (PHB) present in the samples in small amounts (under ~10%), reflecting its partial crystallisation. Drying for 23 h was shown to give more reproducible FTIR spectra of bacterial samples. SeNPs were shown to contain capping layers of proteins, polysaccharides and lipids. The as-prepared SeNPs contained significant amounts of carboxylated components in their bioorganic capping, which appeared to be weakly bound and were largely removed after washing. Spectroscopic characteristics and changes induced by various sample preparation steps are discussed with regard to optimising sample treatment procedures for FTIR spectroscopic analyses of microbiological specimens.