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Despite the already established route of chemically catalyzed transesterification reaction in biodiesel production, due to some of its shortcomings, biocatalysts such as lipases present a vital alternative. Namely, it was noticed that one of the key shortcomings for the optimization of the enzyme catalyzed biodiesel synthesis process is the information on the lipase activity in the reaction mixture. In addition to making optimization difficult, it also makes it impossible to compare the results of the independent research. This article shows how lipase intended for use in biodiesel synthesis can be easily and accurately characterized and what is the enzyme concentration that enables achievement of the desired level of fatty acid methyl esters (FAME) in the final product mixture. Therefore, this study investigated the effect of two different activity loads of Burkholderia cepacia lipase on the biodiesel synthesis varying the pH and temperature optimal for lipase activity. The optimal lipase pH and temperature were determined by two different enzyme assays: spectrophotometric and titrimetric. The B. cepacia lipase pH optimum differentiated between assays, while the lipase optimally hydrolyzed substrates at 50°C. The analysis of FAME during 24 hr of biodiesel synthesis, at two different enzyme concentrations, pH 7, 8, and 10, and using two different buffers, revealed that the transesterification reaction at optimal pH, 1 hr reaction time and lipase activity load of 250 U per gram of reaction mixture was sufficient to produce more than 99% FAME.
Marta Ostojčić; Sandra Budžaki; Ivana Flanjak; Blanka Bilić Rajs; Iva Barišić; Nghiep Nam Tran; Volker Hessel; Ivica Strelec. Production of biodiesel by Burkholderia cepacia lipase as a function of process parameters. Biotechnology Progress 2020, 37, e3109 .
AMA StyleMarta Ostojčić, Sandra Budžaki, Ivana Flanjak, Blanka Bilić Rajs, Iva Barišić, Nghiep Nam Tran, Volker Hessel, Ivica Strelec. Production of biodiesel by Burkholderia cepacia lipase as a function of process parameters. Biotechnology Progress. 2020; 37 (2):e3109.
Chicago/Turabian StyleMarta Ostojčić; Sandra Budžaki; Ivana Flanjak; Blanka Bilić Rajs; Iva Barišić; Nghiep Nam Tran; Volker Hessel; Ivica Strelec. 2020. "Production of biodiesel by Burkholderia cepacia lipase as a function of process parameters." Biotechnology Progress 37, no. 2: e3109.
This study shows that by-products obtained after cold-pressing oil production (flex oil cake, hemp oil cake, hull-less pumpkin oil cake) could be used as substrates for the sustainable and cost-effective production of lipase when cultivating Thermomyces lanuginosus under solid-state conditions (T = 45 °C, t = 9 days). Lipase showed optimum activity at T = 40 °C. The produced lipase extract was purified 17.03-folds with a recovery of 1% after gel chromatography. Three different batch experiments were performed in order to test the possibility of using the lipase in biodiesel production. Experiments were performed with a commercial, unpurified enzyme, and partially purified lipase with sunflower oil and methanol as substrates in a batch reactor at 40 °C. During the experiments, the operational stability of the enzyme was studied. The obtained results clearly showed that produced crude and purified lipase can be used for biodiesel production, but the process needs some additional optimization. As for operation stability, it was noticed that the commercial enzyme was deactivated after 30 h, while produced crude enzyme remained 8.25% of its activity after 368 h.
Marina Tišma; Toma Tadić; Sandra Budžaki; Marta Ostojčić; Anita Šalić; Bruno Zelić; Nghiep Nam Tran; Yung Ngothai; Volker Hessel. Lipase Production by Solid-State Cultivation of Thermomyces Lanuginosus on By-Products from Cold-Pressing Oil Production. Processes 2019, 7, 465 .
AMA StyleMarina Tišma, Toma Tadić, Sandra Budžaki, Marta Ostojčić, Anita Šalić, Bruno Zelić, Nghiep Nam Tran, Yung Ngothai, Volker Hessel. Lipase Production by Solid-State Cultivation of Thermomyces Lanuginosus on By-Products from Cold-Pressing Oil Production. Processes. 2019; 7 (7):465.
Chicago/Turabian StyleMarina Tišma; Toma Tadić; Sandra Budžaki; Marta Ostojčić; Anita Šalić; Bruno Zelić; Nghiep Nam Tran; Yung Ngothai; Volker Hessel. 2019. "Lipase Production by Solid-State Cultivation of Thermomyces Lanuginosus on By-Products from Cold-Pressing Oil Production." Processes 7, no. 7: 465.
Drying as one of the oldest food preservation processes is also the most energy demanding process. Nowadays, when conventional energy sources are declining, reduction/rationalization of energy consumptions in industrial processes is of great importance. One of the more successful ways of saving energy and make the process energy efficient is the integration of heat pumps within the existing technological processes. Heat pump systems are successfully used for different applications such as heating and cooling, and drying as well. In addition, the quality of final dried product is a priority that can be accomplished by heat pump assisted drying systems. This paper presents up-to-date survey in the field of air source heat pump assisted drying of food: fruit, vegetables, herbs and spices.
Sandra Budžaki; Jozo Leko; Kristina Jovanović; Jožef Viszmeg; Ivo Koški. Air source heat pump assisted drying for food applications. Croatian journal of food science and technology 2019, 11, 122 -130.
AMA StyleSandra Budžaki, Jozo Leko, Kristina Jovanović, Jožef Viszmeg, Ivo Koški. Air source heat pump assisted drying for food applications. Croatian journal of food science and technology. 2019; 11 (1):122-130.
Chicago/Turabian StyleSandra Budžaki; Jozo Leko; Kristina Jovanović; Jožef Viszmeg; Ivo Koški. 2019. "Air source heat pump assisted drying for food applications." Croatian journal of food science and technology 11, no. 1: 122-130.
Biodiesel production depends to a great extent on the use of cheap raw materials, since biodiesel itself is a mass product, not a high-value product. New processing methods, such as micro-flow continuous processing combined with enzymatic catalysis, open doors to the latter. As reported here, the window of opportunity in enzyme-catalyzed biodiesel production is the conversion of waste cooking oil. The main technological challenge for this is to obtain efficient immobilization of the lipase catalyst on beads. The beads can be filled into tubular reactors where designed packed-bed provide porous channels, forming micro-flow. It turns out, that in this way, the immobilization costs become the decisive economic factor. This paper reports a solution to that issue. The use of oil cake enables economic viability, which is not given by any of the commercial polymeric substrates used so far for enzyme immobilization. The costs of immobilization are mirrored in the earnings and cash flow of the new biotechnological process.
Sandra Budžaki; Smitha Sundaram; Marina Tišma; Volker Hessel. Cost analysis of oil cake-to-biodiesel production in packed-bed micro-flow reactors with immobilized lipases. Journal of Bioscience and Bioengineering 2019, 128, 98 -102.
AMA StyleSandra Budžaki, Smitha Sundaram, Marina Tišma, Volker Hessel. Cost analysis of oil cake-to-biodiesel production in packed-bed micro-flow reactors with immobilized lipases. Journal of Bioscience and Bioengineering. 2019; 128 (1):98-102.
Chicago/Turabian StyleSandra Budžaki; Smitha Sundaram; Marina Tišma; Volker Hessel. 2019. "Cost analysis of oil cake-to-biodiesel production in packed-bed micro-flow reactors with immobilized lipases." Journal of Bioscience and Bioengineering 128, no. 1: 98-102.
In order to increase the current knowledge on cold‐press oil cakes composition, the present study aims to determine the chemical composition of oil cakes from hull‐less pumpkin (Cucurbita pepo L.), flax (Linum usitatissimum L.), and hemp (Canabis sativa L.) before and after the biological treatment with Trametes versicolor and Humicola grisea using fungal‐based solid‐state technology. After 10 days of treatment, the content of ash, total nitrogen, total proteins, and total organic carbon increased in all three oil cakes, while the content of ether extracts decreased. After treatment, the concentration of soluble carbohydrates decreased in pumpkin and hemp seed oil cakes, whereas it increased in flaxseed oil cake. During treatment with T. versicolor, the content of fructose significantly increased in hull‐less pumpkin seed oil cake. Fiber content decreased in pumpkin and flaxseed oil cakes after treatment with both of the fungi, whereas it increased in flaxseed oil cake. This article is protected by copyright. All rights reserved
Sandra Budžaki; Ivica Strelec; Mija Krnić; Kristina Alilović; Marina Tišma; Bruno Zelić. Proximate analysis of cold-press oil cakes after biological treatment with Trametes versicolor and Humicola grisea. Engineering in Life Sciences 2018, 18, 924 -931.
AMA StyleSandra Budžaki, Ivica Strelec, Mija Krnić, Kristina Alilović, Marina Tišma, Bruno Zelić. Proximate analysis of cold-press oil cakes after biological treatment with Trametes versicolor and Humicola grisea. Engineering in Life Sciences. 2018; 18 (12):924-931.
Chicago/Turabian StyleSandra Budžaki; Ivica Strelec; Mija Krnić; Kristina Alilović; Marina Tišma; Bruno Zelić. 2018. "Proximate analysis of cold-press oil cakes after biological treatment with Trametes versicolor and Humicola grisea." Engineering in Life Sciences 18, no. 12: 924-931.
Grease trap waste has been considered as a cost-effective feedstock for biodiesel production due to its high lipid content and relatively low cost for collection. However, the costly pre-treatment of this contaminated resource is currently the barrier to the commercialization of biodiesel. This study analyses the economic feasibility of biodiesel production from grease trap waste collected in Adelaide (South Australia), focussing on the environmental service providers as the potential biodiesel producers. Based on the experimental results, two different production routes with the same capacity of around 4400 t/year were simulated using Aspen Plus® V8.8, these being; esterification without using acetone as a co-solvent (1); and esterification using a co-solvent of acetone-ethanol (2). The best production price of biodiesel obtained was US$1337.5/t which would indicate that grease trap waste may be a promising feedstock for biodiesel production.
Nghiep Nam Tran; Marina Tišma; Sandra Budžaki; Edward J. McMurchie; Olivia Maria Morales Gonzalez; Volker Hessel; Yung Ngothai. Scale-up and economic analysis of biodiesel production from recycled grease trap waste. Applied Energy 2018, 229, 142 -150.
AMA StyleNghiep Nam Tran, Marina Tišma, Sandra Budžaki, Edward J. McMurchie, Olivia Maria Morales Gonzalez, Volker Hessel, Yung Ngothai. Scale-up and economic analysis of biodiesel production from recycled grease trap waste. Applied Energy. 2018; 229 ():142-150.
Chicago/Turabian StyleNghiep Nam Tran; Marina Tišma; Sandra Budžaki; Edward J. McMurchie; Olivia Maria Morales Gonzalez; Volker Hessel; Yung Ngothai. 2018. "Scale-up and economic analysis of biodiesel production from recycled grease trap waste." Applied Energy 229, no. : 142-150.
M.J. Fernandes; F.C. Pires; J.M. Dias; J Borges; C Alvim-Ferraz; M Almeida; S Budžaki; Cândida Vilarinho; Fernando Castro; Maria De. Formulation of waste mixtures towards effective composting: A case study. WASTES – Solutions, Treatments and Opportunities II 2017, 245 -250.
AMA StyleM.J. Fernandes, F.C. Pires, J.M. Dias, J Borges, C Alvim-Ferraz, M Almeida, S Budžaki, Cândida Vilarinho, Fernando Castro, Maria De. Formulation of waste mixtures towards effective composting: A case study. WASTES – Solutions, Treatments and Opportunities II. 2017; ():245-250.
Chicago/Turabian StyleM.J. Fernandes; F.C. Pires; J.M. Dias; J Borges; C Alvim-Ferraz; M Almeida; S Budžaki; Cândida Vilarinho; Fernando Castro; Maria De. 2017. "Formulation of waste mixtures towards effective composting: A case study." WASTES – Solutions, Treatments and Opportunities II , no. : 245-250.
Sandra Budžaki; Goran Miljić; Marina Tišma; Smitha Sundaram; Volker Hessel. Is there a future for enzymatic biodiesel industrial production in microreactors? Applied Energy 2017, 201, 124 -134.
AMA StyleSandra Budžaki, Goran Miljić, Marina Tišma, Smitha Sundaram, Volker Hessel. Is there a future for enzymatic biodiesel industrial production in microreactors? Applied Energy. 2017; 201 ():124-134.
Chicago/Turabian StyleSandra Budžaki; Goran Miljić; Marina Tišma; Smitha Sundaram; Volker Hessel. 2017. "Is there a future for enzymatic biodiesel industrial production in microreactors?" Applied Energy 201, no. : 124-134.
S. Budžaki. Enzyme-catalysed Biodiesel Production from Edible and Waste Cooking Oils. Chemical & biochemical engineering quarterly 2015, 29, 329 -333.
AMA StyleS. Budžaki. Enzyme-catalysed Biodiesel Production from Edible and Waste Cooking Oils. Chemical & biochemical engineering quarterly. 2015; 29 (3):329-333.
Chicago/Turabian StyleS. Budžaki. 2015. "Enzyme-catalysed Biodiesel Production from Edible and Waste Cooking Oils." Chemical & biochemical engineering quarterly 29, no. 3: 329-333.
Sandra Budžaki; Bernarda Šeruga. Specific Heat of Strawberry and Raspberry Puree. Journal of Food Processing and Preservation 2014, 38, 2240 -2245.
AMA StyleSandra Budžaki, Bernarda Šeruga. Specific Heat of Strawberry and Raspberry Puree. Journal of Food Processing and Preservation. 2014; 38 (6):2240-2245.
Chicago/Turabian StyleSandra Budžaki; Bernarda Šeruga. 2014. "Specific Heat of Strawberry and Raspberry Puree." Journal of Food Processing and Preservation 38, no. 6: 2240-2245.
A line heat source probe method was used to determine thermal conductivity of the Croatian unleavened dough in a temperature range of 27–125°C. For estimation of the specific heat of the Croatian unleavened dough, a mixing method was used. The maximum value of 4.0 ± 0.8 kJ/(kg °C) was determined at 57.1°C for the potato dough, and the minimum value of 1.4 ± 0.6 kJ/(kg °C) was determined at 35.3°C for the Kroštula dough. Thermal conductivity first increased with temperature and then decreased after reaching its maximum value. Minimum value of 0.29 ± 0.04 W/(m °C) was determined at 123.8°C for the Kroštula dough. Further on, a set of empirical equations was established using regression analysis to correlate the results and to predict the specific heat and thermal conductivity of the Croatian unleavened dough within the studied temperature range and moisture levels.
Sandra Budžaki; Bernarda Šeruga. Specific Heat and Thermal Conductivity of the Croatian Unleavened Dough. International Journal of Food Properties 2014, 18, 2300 -2311.
AMA StyleSandra Budžaki, Bernarda Šeruga. Specific Heat and Thermal Conductivity of the Croatian Unleavened Dough. International Journal of Food Properties. 2014; 18 (10):2300-2311.
Chicago/Turabian StyleSandra Budžaki; Bernarda Šeruga. 2014. "Specific Heat and Thermal Conductivity of the Croatian Unleavened Dough." International Journal of Food Properties 18, no. 10: 2300-2311.
The objective of this study was to determine the thermal conductivity of “Mlinci” dough T-500 and “Mlinci” dough T-500 with the addition of eggs, wheat germs and wheat bran in the temperature range of 40°C to 70°C. Thermal conductivity was determined using modifications of guarded hot plate steady state method. For all types of dough, thermal conductivity first increased with temperature and then, after reaching maximum values, it decreased. The maximum values for “Mlinci” dough T-500 containing wheat germs and bran were 54°C, and for “Mlinci” dough T-500 with eggs were 58°C. The minimal value of 0.347 ± 0.020 W/mK was determined for “Mlinci” dough T-500 at 39.38°C. The maximum value 0.585 ± 0.023 W/mK was determined for “Mlinci” dough T-500 with wheat bran at 54.39°C. The thermal conductivity of “Mlinci” dough T-500 with the addition of wheat germs and wheat bran was higher in comparison with the basic composition due to the elevated amounts of ash, water, proteins, and porosity, as well as non-homogeneity. Based on the experimental thermal conductivity values of “Mlinci” dough T-500 samples at various temperatures, quadratic polynomial equations were developed. The research results could be used for the modelling of the heat transfer of “Mlinci” dough T-500 during processing.
B. Seruga; Sandra Budžaki; Ž. Ugarčić-Hardi; M. Šeruga. Effect of temperature and composition on thermal conductivity of “Mlinci” dough. Czech Journal of Food Sciences 2011, 23, 152 -158.
AMA StyleB. Seruga, Sandra Budžaki, Ž. Ugarčić-Hardi, M. Šeruga. Effect of temperature and composition on thermal conductivity of “Mlinci” dough. Czech Journal of Food Sciences. 2011; 23 (No. 4):152-158.
Chicago/Turabian StyleB. Seruga; Sandra Budžaki; Ž. Ugarčić-Hardi; M. Šeruga. 2011. "Effect of temperature and composition on thermal conductivity of “Mlinci” dough." Czech Journal of Food Sciences 23, no. No. 4: 152-158.
In this study, the influence of oil temperature, water migration and surface temperature of “Kroštula” dough on convective heat transfer coefficient was investigated. The convective heat transfer coefficient during deep fat frying was determined at temperatures 160, 170, 180 and 190±1 °C. Heat transfer coefficient was the highest at the start of deep fat frying process; 579.12±2.46, 583.88±1.81, 597.05±1.10 and 657.91±0.95 W/m2 K for 160, 170, 180 and 190 °C of oil temperature, respectively. The smallest heat transfer coefficient was in the case of setting up a uniform period of water migration from sample, which corresponded to surface temperatures slightly higher than 100 °C; 26.53±0.63, 14.42±0.56, 56.78±0.49 and 37.52±0.54 W/m2 K for 160, 170, 180 and 190 °C of oil temperature, respectively. Higher oil temperature for deep fat frying increased values of heat transfer coefficient. A steady-state method was used to determine thermal conductivity of “Kroštula” dough in temperature range of 40–70±1 °C. The thermal conductivity first increased with temperature and then after reaching maximum values decreased. The maximum value 0.5985±0.0196 W/(m K) was determined at 47.5 °C. The minimal value 0.4723±0.0192 W/(m K) was determined at 65 °C.
Bernarda Šeruga; Sandra Budžaki. Determination of thermal conductivity and convective heat transfer coefficient during deep fat frying of “Kroštula” dough. European Food Research and Technology 2005, 221, 351 -356.
AMA StyleBernarda Šeruga, Sandra Budžaki. Determination of thermal conductivity and convective heat transfer coefficient during deep fat frying of “Kroštula” dough. European Food Research and Technology. 2005; 221 (3-4):351-356.
Chicago/Turabian StyleBernarda Šeruga; Sandra Budžaki. 2005. "Determination of thermal conductivity and convective heat transfer coefficient during deep fat frying of “Kroštula” dough." European Food Research and Technology 221, no. 3-4: 351-356.
S. Budžaki; B. Seruga. Determination of convective heat transfer coefficient during frying of potato dough. Journal of Food Engineering 2005, 66, 307 -314.
AMA StyleS. Budžaki, B. Seruga. Determination of convective heat transfer coefficient during frying of potato dough. Journal of Food Engineering. 2005; 66 (3):307-314.
Chicago/Turabian StyleS. Budžaki; B. Seruga. 2005. "Determination of convective heat transfer coefficient during frying of potato dough." Journal of Food Engineering 66, no. 3: 307-314.
The mechanism of moisture transfer by diffusion and uptake of frying oil was studied during deep fat frying of “Kroštula” dough with an initial moisture content of 0.4358 kg/kg (db). The experimental data were found to fit well to a first-order exponential model for moisture transfer (with a regression coefficient of 0.99). The effective moisture diffusivity of Kroštula dough was determined for two periods of moisture loss (intensive in first 60 s and constant after 60 s of frying). In the frying range 0–60 s at temperatures of 160, 170, 180 and 190±1 °C, the effective moisture diffusivity values were 5.837, 6.607, 8.472 and 9.728×10−9 m2/s, from which the activation energy (30 kJ/mol) was calculated by using an Arrhenius-type equation. The effective oil diffusivity values of Kroštula dough in the frying time range 0–210 s at temperatures of 160, 170, 180 and 190±1 °C were 0.932, 1.135, 1.094 and 1.054×10−9 m2/s, from which the activation energy (5.5 kJ/mol) was calculated by using an Arrhenius-type equation.
Sandra Budžaki; Bernarda Šeruga. Moisture loss and oil uptake during deep fat frying of “Kroštula” dough. European Food Research and Technology 2004, 220, 90 -95.
AMA StyleSandra Budžaki, Bernarda Šeruga. Moisture loss and oil uptake during deep fat frying of “Kroštula” dough. European Food Research and Technology. 2004; 220 (1):90-95.
Chicago/Turabian StyleSandra Budžaki; Bernarda Šeruga. 2004. "Moisture loss and oil uptake during deep fat frying of “Kroštula” dough." European Food Research and Technology 220, no. 1: 90-95.