Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2026/r/gumushane/13623
  Layered Polymeric Carbon Nitride as a Green Support for Cellulase Immobilization: Improved Stability, Activity, and Reusability

  Gulesci, Nuri; Altan, Orhan; Toprak, Ali; Yalçın, M. Serkan; Bilgin, Ramazan; Yildirim, Deniz

  Polymeric carbon nitride (PCN) has attracted considerable attention in recent years due to its layered structure and donor groups such as terminal amines and triazine units. In this study, PCN was synthesized from melamine and employed for the first time as a support material for the immobilization of cellulase, a key enzyme used in numerous industrial applications. Transmission electron microscopy (TEM) analysis revealed that ranged from 219 to 375 nm in size, thereby confirming their nanoscale layered morphology. Cellulase from Aspergillus sp. was immobilized onto PCN using three methods. In the first approach, cellulase was adsorbed onto PCN to form PCN@cellulase. In the second method, PCN@cellulase was cross-linked with glutaraldehyde (PCN@cellulase/Glu). Finally, the primary amino group of PCN was modified with glutaraldehyde, and the cellulase was immobilized onto this support via covalent attachment (PCN/Glu@cellulase). Each cellulase preparation was assessed for its optimal pH, temperature conditions, thermal stability, and enzyme kinetics. The optimal pH was 5.5 for all cellulase preparations, while the optimal temperature was 45 °C for free cellulase and 55 °C for all immobilized cellulase preparations. Thermal stability of PCN@cellulase, PCN@cellulase/Glu, and PCN/Glu@cellulase increased by 2.1-, 2.7-, and 3.7-fold, respectively, compared to the free cellulase. PCN/Glu@cellulase showed a 1.4-fold higher catalytic efficiency than the free cellulase and retained 80% of its initial activity after 10 reuses. This work highlights PCN as a green, metal-free, and easy-to-prepare support for enzyme immobilization, thereby opening new possibilities for sustainable bioprocessing applications.

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• MakaleAçık Erişim2024/r/gumushane/14326
  Gluconic Acid Production by Using Recombinant Escherichia coli Waksman pqq+ Cells with a Novel Approach from Biomass Sources

  Gül, Abdulkadir; Tanyıldızı, Muhammet Şaban

  Gluconic acid (GA) is widely used in the pharmaceutical, food, detergent, textile, leather, and concrete industries. However, cost-effective and high-yield production of GA remains a challenge. Due to currently high raw material inputs of GA, various alternative carbohydrate sources are being investigated. Sucrose is one of the cost-effective biomass sources that can be used as feedstock. The most common industrial production of GA is based on wild-type bacteria and fungi, but there are many problems with this production. This study aimed to optimize the production of GA from glucose produced by hydrolysis of sucrose using recombinant E. coli Waksman (W) pqq+ strain. After sucrose was enzymatically hydrolyzed, significant medium components for GA production were determined as glucose, calcium carbonate (CaCO3), peptone, and ammonium phosphate ((NH4)3PO4) using Placket-Burman Design (PBD). Detailed optimization of the medium components that are significant in GA production was carried out using central composite design (CCD), and optimum values of the independent variables examined in maximum GA production (93.5 ± 2.95 g/L) were determined as glucose 95, CaCO3 25, peptone 2, and (NH4)3PO4 1.13 (g/L). Using results obtained in the Erlenmeyer experiments, GA production in the bioreactor was investigated by CCD. The maximum GA efficiency (3.20 ± 0.15 g/L. h) was obtained under conditions where the air supply rate was 10.82 L/min, stirring speed was 656.87 rpm, and CaCO3 concentration was 16.90 g/L. In conclusion, it has been shown that GA can be produced with a high yield with this novel approach using a recombinant strain for GA production from sucrose.

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• MakaleAçık Erişim2024/r/gumushane/12720
  Investigation of Antibiofilm and Antibacterial Properties of Green Synthesized Silver Nanoparticles from Aqueous Extract of Rumex sp.

  Akay, Seref; Yüksel, Gamze; Özad Düzgün, Azer

  The decrease in the effectiveness of conventional drugs as a result of the growth of resistance to antibiotics has increased the need for innovative tools to control the infections. At this point, metallic nanoparticles, in particular silver nanoparticles, have appeared as a promising method. In the current study, the extract of Rumex sp. (Labada, dock) leaves was used as a reducing agent for the formation of silver nanoparticles. Unlike similar studies, in this study the synthesis conditions were optimized by changing the extract ratio and silver nitrate concentration. Morphological investigations of synthesized silver nanoparticles showed that spherical homogeneous particles at size under 100 nm had been produced. SEM/EDS and FTIR analyses showed that plant components are involved in the synthesis of nanoparticles. It was also determined that higher extract ratio reduced nanoparticle size. The antimicrobial effects of the synthesized nanoparticles against Gram-positive and Gram-negative bacteria were tested, and it was determined that all nanoparticles exhibited activity against both groups. Rumex sp. silver nanoparticles (NPs) were revealed to exhibit antibiofilm activity against three different isolates with moderate and strong biofilm-forming ability. The NPs reduced the biofilm-forming capacity of Acinetobacter baumannii and Klebsiella pneumonaie by 2.66-fold and 3.25-fold, whereas they decreased the Escherichia coli biofilm-forming capacity by 1.25-fold. The investigation of microbial biofilm could play an important role in developing new strategies for treatment options. Our results suggest that Rumex sp. silver NPs may have a high potential for use in the treatment of pathogenic strains.

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• MakaleAçık Erişim2024/r/gumushane/12580
  Determination of the Cytotoxicity and Antibiofilm Potential Effect of Equisetum arvense Silver Nanoparticles

  Akar, Zeynep; Akay, Seref; Ejder, Nebahat; Özad Düzgün, Azer

  This study aimed to synthesize and characterize silver nanoparticles (AgNPs) by green synthesis from Equisetum arvense (Ea) extracts and to investigate their cytotoxicity, antibiofilm activity, and α-glucosidase enzyme inhibition. Diverse characterization techniques were applied to verify the production of nanoparticles. SEM examination confirmed that the size of nanoparticles is in the range of 40–60 nm. Also, interactions between silver and natural compounds of plant extract were confirmed through FT-IR and EDX analyses. It was determined that Equisetum arvense silver nanoparticles had antibiofilm activity against three different clinical strains with high biofilm-forming ability. AgNPs reduced the biofilm-forming capacity of clinical A. baumannii isolate with strong biofilm-forming capacity by approximately twofold, while the capacity of clinical K.pneumonaie and E.coli isolates decreased by 1.5 and 1.2 fold, respectively. The α-glucosidase enzyme inhibition potential of the AgNPs, which is determined as 93.50%, was higher than the plant extract with, and the α- 30.37%. MTT was performed to assess whether incubation of nanoparticles with A549 and ARPE-19 cell lines affected their viability, and a dramatic reduction in cell growth inhibition of both A549 and ARPE-19 cells was observed. It has been shown that A549 cells treated with 200 and 150 µg/mL nanoparticles had less cell proliferation compared to control cells at 24-h and 48-h incubation time. According to these results, Ea-derived AgNPs appear to have potential anticancer activity against A549 cancer cells. Investigating the effects of green synthesis nanoparticles on microbial biofilm and various tumors may be important for developing new therapies. The outcomes of this study have showed that Ea-AgNPsmay have a high potential both in the treatment of pathogenic strains that form biofilms, as well as in anticancer therapy use.

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