Akademik Veri Yönetim Sistemi
Journal of Polymers and the Environment, cilt.31, sa.12, ss.5355-5370, 2023 (SCI-Expanded)
In this study, levan biopolymer (a fructose-based exopolysaccharide) was produced by Paenibacillus polymyxa HCT33-3, which was immobilized onto the composite of silica-coated magnetite nanoparticles (Fe3O4@SiO2 NPs). For this purpose, firstly, synthesis of magnetite nanoparticles (Fe3O4 NPs) was followed by Fe3O4@SiO2 composite formation to enhance its stability. The characterization studies were investigated with the scanning electron microscopy and energy dispersive X-ray analyzes, transmission electron microscopy, X-ray diffraction analyses. Then, the microorganism Paenibacillus polymyxa HCT33-3, immobilized onto Fe3O4@SiO2 and levan fermentation was carried out in the media including molasses. Effects of molasses percentage in the growth media, initial pH, temperature and fermentation period parameters were tested on levan production capability. The highest levan concentration of 35.8 g/L was obtained at the 54th hour in the medium including 20% molasses (v/v) with the initial pH and temperature values of 7.0 and 37 °C, respectively. The characterization studies clearly confirmed that the produced exopolysaccharide was levan, which showed an antimicrobial effect against all microorganisms used in the study, besides its effectiveness on the biofilm formed by Pseudomonas aeruginosa. This is the first study focusing on high-value levan biopolymer production by the immobilized microorganisms onto Fe3O4@SiO2 nanocomposite in the growth media including molasses as the sole carbon source. This environmentally friendly process, which can potentially enable the repeated use of the cells, seemed to be significantly advantageous in terms of both cost and sustainability.