Antimicrobial activity and biodegradation of natural cellulose fibre blends with embedded ZnO

Mikroorganizmi poleg svojih številnih pozitivnih učinkov, kot je na primer biorazgradnja organskih snovi, predstavljajo tudi problem z vidika prenosa bolezni in negativnih vplivov na funkcionalne lastnosti tekstilij. V raziskavi smo proučevali vpliv nanodelcev ZnO na protimikrobno zaščito in stopnjo biorazgradnje mešanic naravnih celuloznih vlaken, z vključenimi protimikrobnimi vlakni liocel v različnih deležih. Protimikrobne teste za bakterije vrst Staphylococcus aureus in Escherichia coli smo izvedli po standardni metodi ASTM E 2149-01. Pri bakterijah vrste E. coli smo opazili značilen trend naraščanja protimikrobne zaščite s povečevanjem deleža protimikrobnih vlaken v mešanici, za pojasnitev odstopajočih rezultatov pri bakterijah vrste S. aureus pa smo izvedli še dodatne teste rasti in adhezije bakterij na posamezna vlakna. Ugotovili smo, da lanena vlakna predstavljajo primeren substrat za rast bakterij vrste S. aureus in da se bakterije nanj po določenem času pritrdijo in zaščitijo s tvorbo biofilma. V drugem delu raziskave o biorazgradnji vlaken smo izbrali mešanico vlaken s 25 % vlaken liocel, ki je dosegla zadovoljivo protimikrobno zaščito pri bakterijah vrste E. coli. Za namen določanja stopnje biorazgradnje smo mešanico skupaj s kontrolnimi vzorci zakopali v humusno ilovico. Po določenih intervalih zakopa smo določili fizikalne in kemijske lastnosti vlaken, za ugotovitev stopnje kontaminacije zemlje pa smo preučili tudi kaljenje semen. Ugotovili smo, da je povišanje količine protimikrobnih vlaken v mešanic vplivalo na zmanjšanje stopnje biorazgradnje mešanice in hkrati ni vplivalo na kontaminacijo zemlje.Microorganisms, in addition to many positive effects such as biological decomposition of organic matters, represent a problem because they cause infectious diseases and adversely affect functional properties of textiles. The main aim of the research was to study the influence of ZnO nanoparticles on the antimicrobial activity and biodegradation of natural cellulose fibre blends including different proportions of lyocell antimicrobial fibres. Antimicrobial tests for Staphylococcus aureus and Escherichia coli were carried out according the ASTM E 2149-01 standard method. A significant trend in the increase of antimicrobial activity with the increase of the proportion of antimicrobial fibres in the blends was observed for E. coli. Additional tests of bacterial growth and adhesion to individual fibres were performed to clarify the divergent results which were obtained for S. aureus. It was found out that the flax fibres represent a suitable substrate for the growth of S. aureus and that the bacteria adhere to the fibres after a certain period of time and protect themselves by forming a biofilm. In the second part of the research, a fibre blend including 25% lyocell fibres, that provided a satisfactory antimicrobial protection for E. coli, was chosen for biodegradation experiments. In this study, the fibre blend and the control samples were buried into the humus soil. Physical and chemical properties of fibres were analysed after certain intervals of soil burial. To determine the level of the soil contamination, the seed germination was also studied. The results showed that an increase in the proportion of antimicrobial fibres in the blend caused a decrease in the blend biodegradability and at the same time had no effect on the soil contamination