Mikrobiološko iskorišćenje otpadnog glicerola iz proizvodnje biodizela
Committee membersVeljković, Vlada
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Three-hydroxyl alcohol glicerol, obtained during the biodiesel production, can be observed as a crude glicerol fraction because of the impurity content. Current researches around the world are aimed at studying the possibilities of converting waste glicerol into various products. Glicerol can be used as the main source of carbon in media for industrial fermentations. This dissertation was studying the possibility of microbial utilization of waste glicerol, obtained as a by-product in the production of biodiesel from sunflower and rapeseed oil, using Enterococcus faecalis MK3-10A lactic acid bacteria, Streptomyces hygroscopicus CH-7 bacteria and freshwater microalgae. Bacteria E. faecalis MK3-10A did not produce a significant amount of lactic acid.The highest production of 14,64 mg/ml/d was achieved in medium containing waste glicerol obtained in biodiesel production from sunflower oil. Depending on the medium, consumption of glicerol was 21-37 %. Cultivating in media containing waste g...licerol, as opposed to media with glucose, bacteria S. hygroscopicus CH-7 showed lower growth and did not produce significantly higher amounts of antibiotics. However, addition of isatin derivatives, as a nitrogen source, significantly increased the production of antibiotics. Isatin-3-hydrazone shows the best influence on the antibiotics production, wherein the maximum concentration of hexaene H-85 (196 μg/ml) and azalomycine B (75μg/ml) was obtained. An isolated strain of algae, characterized as a member of genus Chlorococcum, grows well and consume all of available quantity of clean and waste glicerol from sunflower oil, as well as significant amount of glicerol from rapeseed oil (61 %), but in comparison to other isolated strains of algae it produces the least amount of microbial oil (15-23 %). Regardless of weaker growth and consumption of glicerol, Chlorella and Scenedesmus strains produce the most microbial oil (27-35 %). The general conclusion of this thesis is that the waste glicerol obtained in biodiesel production from rapeseed oil is less suitable, as a carbon source, for cultivation of bacteria E. faecalis MK3-10A, because of impurities it contains. Therefore, it is necessary to purify it before using, except in the case of antibiotic azalomycine B production by S.hygroscopicus CH-7 with addition of isatin derivatives, as well as microbial oil production by freshwater algae. As opposed to that, waste glicerol from sunflower oil can be used without purification, because it was more efficient in production of lactic acid, antibiotic hexane and algae oil than the pure glicerol.