Browsing by Subject "biosidi"

Abstract This work was done at R&D Center of Kemira Oy in Espoo. Paper machines are open systems which are impossible to keep sterile. Paper machines offer favourable conditions for microbial growth. Microbiological problems in paper industry have been reported for years and expanding the production facilities and recycling of process waters have increased microbial growth. Microorganisms cause a lot of problems in paper machines and contaminatios can lead to huge economical loses. Biofilms can block filters and nozzles. Biofilms cause production breakdowns. The quality of produced paper is deteriorated, produced paper can have holes and discalourations. Sometimes the paper machine has to be stopped. Biofilms also increase the corrosion of machinery. Biocides are commonly used to control the formation of biofilms. Biocides are dosed with process waters and they are not specific to biofilm forming bacteria. Biofilms tolerate biocides better than planktonic bacteria and the biofilm problem has not been able to solve. There are a lot of different microbes found on paper making processes. Paper machines can contain viruses, bacteria, syanobacteria, molds, yeasts, algae ja protozoa. Paper machines environment and location, temperature, pH, raw materials and other additives have impact on the composition of microbe population. Kemira has a targeted-release biocide product on the market. Polymeric micelles protect biocidal active agents from degradation while it has been delivered to the targeted surfaces. Global patent has been applied for this targeted-release technology. Target of this work was to develop a cheaper version of this product having same targeted effects and better storage stability In this work the stability, efficacy against planktonic cells and against biofilm were tested. qPCR and sequencing were used to test the effect of the biocide to microbe population.