Yazar "Akkurt, Seyma" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim Yok
    Öğe
    Equilibrium, kinetic, and thermodynamic studies on the biosorption of lead by human metallothionein gene-cloned bacteria as a novel biosorbent
    (Wiley, 2024) Akkurt, Seyma; Uckun, Aysel Alkan; Oguz, Merve; Uckun, Mirac; Kahraman, Huseyin
    Heavy metals are the main pollutants in water and are an important global problem that threatens human health and ecosystems. In recent years, there has been an increasing interest in the use of genetically modified bacteria as an eco-friendly method to solve heavy metal pollution problems. The goal of this study was to generate genetically modified Escherichia coli expressing human metallothioneins (hMT2A and hMT3) and to determine their tolerance, bioaccumulation, and biosorption capacity to lead (Pb2+). Recombinant MT2A and MT3 strains expressing MT were successfully generated. Minimum inhibition concentrations (MIC) of Pb for MT2A and MT3 were found to be 1750 and 2000 mg L-1, respectively. Pb2+ resistance and bioaccumulation capacity of MT3 were higher than MT2A. Therefore, only MT3 biosorbent was used in Pb2+ biosorption, and its efficiency was examined by performing experiments in a batch system. Pb2+ biosorption by MT3 was evaluated in terms of isotherms, kinetics, and thermodynamics. The results showed that Pb biosorption fits to the Langmuir isotherm model and the pseudo-first-order kinetic model, and the reaction is exothermic. The maximum Pb2+ capacity of the biosorbent was 50 mg Pb2+g-1. The potential of MT3 in Pb biosorption was characterized by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and scanning transmission electron microscopy (STEM) analyses. The desorption study showed that the sorbent had up to 74% recovery and could be effectively used four times. These findings imply that this biosorbent can be applied as a promising, precise, and effective means of removing Pb2+ from contaminated waters.Practitioner Points In this study, the tolerance levels, bioaccumulation, and biosorption capacities of Pb in aqueous solutions were determined for the first time in recombinant MT2A and MT3 strains in which human MT2A and MT3 genes were cloned. The biosorbent of MT3, which was determined to be more effective in Pb bioaccumulation, was synthesized and used in Pb biosorption. The Pb biosorption mechanism of MT3 biosorbent was identified using isotherm modeling, kinetic modeling, and thermodynamic studies. The maximum Pb removal percentage capacity of the biosorbent was 90%, whereas the maximum biosorption capacity was up to 50 mg Pb2+g-1. These results indicated that MT3 biosorbent has a higher Pb biosorption capacity than existing recombinant biosorbents. MT3 biosorbent can be used as a promising and effective biosorbent for removing Pb from wastewater. In this study, genetically modified bacteria were used to remove Pb+2 from water, which is an important global problem. To our knowledge, tolerance levels, bioaccumulation, and biosorption capacities of Pb+2 from aqueous solutions of MT2A and MT3 recombinant strains were determined for the first time in this study. MT3 biosorbent can be used as an effective tool for Pb+2 biosorption from water. image
  • Küçük Resim Yok
    Öğe
    Fabrication, characterization, and application of laccase-immobilized membranes for acetamiprid and diuron degradation
    (Elsevier, 2024) Ulu, Ahmet; Akkurt, Seyma; Birhanli, Emre; Uckun, Aysel Alkan; Uckun, Mirac; Yesilada, Ozfer; Ates, Burhan
    Water and wastewater pollution by acetamiprid and diuron is considered a serious environmental problem. In this study, chitosan (CHS), a naturally occurring bioadsorbent considered ecologically harmless to remove these micropollutants, was developed as a possible carrier to immobilize laccase (Lac) from Trametes trogii. Polyethylene glycol methyl ether (PEGME) was chosen for blending CHS, so a hybrid biocatalyst-based Lac/CHSPEGME membrane was prepared. The prepared CHS-PEGME and Lac/CHS-PEGME membranes were characterized by Fourier-transformed-infrared (FTIR) spectroscopy, scanning-electron-microscopy (SEM), and X-raydiffraction (XRD). Pesticide degradation tests with Lac/CHS-PEGME were performed at different contact times and initial concentrations. Acetamiprid degradation was most effective (84 %) at the 12th hour, at an initial concentration of 0.1 mg/L, while diuron degradation was most effective (65 %) at an initial concentration of 6 mg/L and a contact time of 16th hour. Under optimum conditions, the reusability of Lac/CHS-PEGME was found to be 8 cycles for acetamiprid and 5 cycles for diuron. From these results, it is understood that acetamiprid is degraded more quickly and effectively than diuron. Adsorption process data were well fitted to the Langmuir isotherm model and the pseudo-first-order kinetic model. These findings showed that using Lac/CHS-PEGME was a practical and environmentally friendly method for acetamiprid and diuron degradation.
  • Küçük Resim Yok
    Öğe
    Immobilization of laccase isolated from Trametes trogii on chitosan-based membrane and its application in the biodegradation of atrazine and trifloxystrobin pesticides
    (Springer, 2025) Uckun, Aysel Alkan; Uckun, Mirac; Akkurt, Seyma; Birhanli, Emre; Bakar, Busra; Ulu, Ahmet; Yesilada, Ozfer
    Recently, focus has been placed on various enzyme immobilization applications as effective, eco-friendly, and low-cost methods for the degradation of pesticides in water. Laccases are very effective biocatalysts that are frequently used in environmental remediation applications. In this research, the use of a biocatalyst obtained by immobilizing laccase purified from Trametes trogii on chitosan-polyethylene glycol methyl ether (Lac/CH/MPEG) in the degradation of atrazine (ATR) and trifloxystrobin (TFS) pesticides in water was investigated. The degradation of these pesticides with this synthesized biocatalyst is the first in the literature. Therefore, primarily, the basic physicochemical parameters and mechanical properties of Lac/CH/MPEG prepared before and after immobilization were investigated. Structural analysis and morphological imaging of Lac/CH/MPEG before and after degradation of ATR and TFS were also performed. In the degradation tests, the initial concentrations at which optimum degradation rates were observed for ATR (72%) and TFS (85%) were 1 mg L-1 and 0.5 mg L-1, and the contact times were 24 h and 12 h, respectively. Additionally, the reuse cycles of Lac/CH/MPEG in ATR and TFS degradation were found to be 5 and 6, respectively. These findings showed that TFS was degraded faster and more effectively than ATR. Compared to several biocatalysts in the literature, ours was shown to degrade pesticides more quickly and efficiently. Considering all the findings, it can be concluded that this novel Lac/CH/MPEG biocatalysts is promising, can be applied, and can be successfully used as an alternative agent for quick and efficient degradation of ATR and TFS in water/wastewater.