MİKROBİYAL BİYOPOLİMER ÜRETİMİ VE ANTİMİKROBİYAL YÜZEY OLARAK KULLANIMININ ARAŞTIRILMASI

Abstract

Levan is a homopolymer of fructose naturally obtained from both plants and microorganisms. Along with the general properties of a biopolymer like bio-compatibility, bio-degradability, renewability, flexi-bility, and eco-friendliness, levan also offers some important biomedical properties such as anti-oxidant,anti-inflammatory, anti-carcinogenic, anti-AIDS and hyperglycaemic inhibitör. Due to its exceptionally high production costs, levan could never find its proper place in the polymer market, and therefore, high-level levan producing microbial systems gain escalating industrial importance. Antimicrobial peptides and their precursor molecules form a central part of human and mammalian innate immunity. The hCAP18/LL37 is the only known human cathelicidin. In the skin, LL-37/mCRAMP is required to prevent invasive bacterial infections. Besides its an antimicrobial properties LL-37 plays a central role in innate immune responses and inflammation. In this study, we isolated several soil microorganisms which where levan producers. Pseudomonas mandelii is the microorganism used for production of levan in this study. The biopolymer was analyzed with CNMR, HNMR, FTIR and the results comfirmed that the polymer was levan. The highest amount of levan was achieved by optimizing the incubation time, pH, temperature, sugar amount, nitrogen, carbon source of the produced polymer. After the optimization, the highest amount of levan produced by Pseudomonas mandelii was found to be 42.6 g/L. The conversion yield and effective yield were calculated as 37.8% and 27.7% respectively. Various film samples with different ingredients and levan were prepared, and glycerol was chosen as the plasticizer. Film samples were evaluated for water vapor permeability and thermogravimetric analysis (TGA). Antimicrobial properties were determined on different microorganisms by adding LL-37 antimicrobial peptides in varying amounts to the film samples. The antimicrobial effect of antibiotics used in wound treatment and the antimicrobial effect of film compositions were evaluated comparatively. It was determined that LL-37 biopolymer films had an antimicrobial effect on E. coli, S. aureus, Candida albicans and Aspergillus niger. The antimicrobial effect of the film specimens, especially on Candida albicans, was higher than all the antibiotics tested. This biodegradable polymer film is supported by the work we have done in the treatment of medical field wounds, as bandages, wound dressings, food packaging and as an antimicrobial surface for many fields.