Sanja Grbavčić
University of Belgrade
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Featured researches published by Sanja Grbavčić.
Bioresource Technology | 2011
Sanja Grbavčić; Dejan Bezbradica; Lidija Izrael-Živković; Nataša Avramović; Nenad Milosavić; Ivanka Karadžić; Zorica Knežević-Jugović
An indigenous Pseudomonas aeruginosa strain has been studied for lipase and protease activities for their potential application in detergents. Produced enzymes were investigated in order to assess their compatibility with several surfactants, oxidizing agents and commercial detergents. The crude lipase appeared to retain high activity and stability in the presence of several surfactants and oxidizing agents and it was insusceptible to proteolysis. Lutensol® XP80 and Triton® X-100 strongly activated the lipase for a long period (up to 40 and 30% against the control after 1h) while the protease activity was enhanced by the addition of Triton® WR1339 and Tween® 80. The washing performance of the investigated surfactants was significantly improved with the addition of the crude enzyme preparation. Studies were further undertaken to improve enzymes production. The optimization of fermentation conditions led to an 8-fold increase of lipase production, while the production of protease was enhanced by 60%.
Bioresource Technology | 2017
Abdalla Ali Salim; Sanja Grbavčić; Nataša Ž. Šekuljica; Andrea B. Stefanović; Sonja Jakovetić Tanasković; Nevena Luković; Zorica Knežević-Jugović
Study on potential of different agro-industrial waste residues for supporting the growth of newly isolated Bacillus sp. TMF-1 strain under solid-state fermentation (SSF) was conducted aiming to produce several industrially valuable enzymes. Since the feasibility of the initial study was confirmed, further objectives included evaluation of several pretreatments of the studied agricultural by-products (soybean meal, sunflower meal, maize bran, maize pericarp, olive oil cake and wheat bran) on the microbial productivity as means of enhancing the yields of produced proteases, α-amylases, cellulases and pectinases. Among acid/alkaline treatment, ultrasound and microwave assisted methods, chemical treatments superiorly affected most of the studied substrates. Highest yields of produced proteases (50.5IUg-1) and α-amylases (50.75IUg-1) were achieved on alkaline treated corn pericarp. Alkaline treatment also promoted the secretion of cellulases on maize bran (1.19IUg-1). Highest yield of pectinases was obtained on untreated soybean meal (64.90IUg-1).
Methods of Molecular Biology | 2017
Zorica Knežević-Jugović; Sanja Grbavčić; Jelena R. Jovanović; Andrea B. Stefanović; Dejan Bezbradica; Dušan Ž. Mijin; Mirjana G. Antov
A selection of best combination of adequate immobilization support and efficient immobilization method is still a key requirement for successful application of immobilized enzymes on an industrial level. Eupergit® supports exhibit good mechanical and chemical properties and allow establishment of satisfactory hydrodynamic regime in enzyme reactors. This is advantageous for their wide application in enzyme immobilization after finding the most favorable immobilization method. Methods for enzyme immobilization that have been previously reported as efficient considering the obtained activity of immobilized enzyme are presented: direct binding to polymers via their epoxy groups, binding to polymers via a spacer made from ethylene diamine/glutaraldehyde, and coupling the periodate-oxidized sugar moieties of the enzymes to the polymer beads. The modification of the conventionally immobilized enzyme with ethylenediamine via the carbodiimide route seems to be a powerful tool to improve its stability and catalytic activity.
Hemijska Industrija | 2010
Milena R. Bradić; Nevena Ognjanovic; Dejan Bezbradica; Sanja Grbavčić; Nataša Avramović; Dušan Ž. Mijin; Zorica Knežević-Jugović
Monoacylglycerols are non-ionic surfactants widely used in the food industry. They are also important in cosmetic and pharmaceutical industries as drug carriers and for the consistency improvements in creams and lotions. Current process for their production is based on the glycerolysis of natural fats and oils in the presence of inorganic catalysts at temperatures higher than 220 oC. The major drawbacks of this process include high-energy consumption, low yield, and poor product quality. The use of lipases for the monoacylglycerols production offers environmental advantages and a reduction in energy consumption. Besides, the same surfactants prepared by the enzymatic synthesis may be labeled as “natural”. Recent progress in the application of highly-stable lipases in the organic solvents offers the possibility of employing various methods to the enzyme-catalyzed synthesis of monoacylglycerols, such as selective hydrolysis of fats and oils using 1,3-regiospecific lipases, the esterification of glycerol with fatty acids and the glycerolysis of fats or oils. In this review, different reaction systems such as aqueous-organic two-phase systems, microemulsions and reverse micelles systems, anhydrous organic solvents, solvent-free systems with free or immobilized lipases, as well as the use of two-phase membrane reactor systems are presented. We discuss some of the key factors, such as the control of water content, removing of the products from reaction system, and the effects of solvent on the lipase activity and selectivity, that must be addressed in order to obtain an efficient reaction system with high yields of monoacylglycerols. Engineering of the enzymatic monoacylglycerols synthesis processes requires also optimization of other factors as: molar ratio of substrates, temperature, type of lipase immobilization and supports (if any), reactor design and operating regime.
European Food Research and Technology | 2014
Andrea B. Stefanović; Jelena R. Jovanović; Sanja Grbavčić; Nataša Ž. Šekuljica; Verica Manojlovic; Branko Bugarski; Zorica Knežević-Jugović
Applied Biochemistry and Biotechnology | 2012
Omar Ali Saied Moftah; Sanja Grbavčić; Milena G. Žuža; Nevena Luković; Dejan Bezbradica; Zorica Knežević-Jugović
Applied Clay Science | 2017
Sonja Jakovetić Tanasković; Bojan Jokić; Sanja Grbavčić; Ivana Drvenica; Nevena Ž. Prlainović; Nevena Luković; Zorica Knežević-Jugović
Hemijska Industrija | 2014
Milica Carević; Maja Vukašinović-Sekulić; Sanja Grbavčić; Marija Stojanović; Mladen Mihailović; Aleksandra Dimitrijević; Dejan Bezbradica
Food and Bioprocess Technology | 2015
Sonja M. Jakovetić; Nevena Luković; Branimir Z. Jugović; Milica M. Gvozdenović; Sanja Grbavčić; Jelena Jovanovic; Zorica Knežević-Jugović
Journal of Surfactants and Detergents | 2015
Sanja Grbavčić; Darka Marković; Mirjana Rajilić-Stojanović; Mirjana G. Antov; Marina B. Šćiban; Ivanka Karadžić; Zorica Knežević-Jugović