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Papers by Ljiljana Mojovic

Developments in food science, 1992

SUMMARY Regiospecific interesterification of triacylglycerols of palm oil mid fraction with stear... more SUMMARY Regiospecific interesterification of triacylglycerols of palm oil mid fraction with stearic acid by lipase from Rhizopus arrhizus immobilized on inorganic support was studied, for the purpose of cocoa buter-like fat production. Addition of 5% of crude soybean lechitin on the mass of immobilized enzyme caused valuable increase of stearic acid content in interesterified triacylglycerols. It is considered that lechitin acts as a surface active agent and forms reverse micellar system arround immobilized and hydrated enzyme in n-hexane.

Journal of bioscience and bioengineering, Jan 20, 2016

Lactic acid bacteria immobilization methods have been widely used for lactic acid production. Unt... more Lactic acid bacteria immobilization methods have been widely used for lactic acid production. Until now, the most common immobilization matrix used is calcium alginate. However, Ca-alginate gel disintegrated during lactic acid fermentation. To overcome this deficiency, we developed an immobilization method in which Lactobacillus rhamnosus cells were successfully encapsulated into an ordered mesoporous silica-based material under mild conditions with a high immobilization efficiency of 78.77% by using elemental analysis. We also optimized the cultivation conditions of the immobilized L. rhamnosus and obtained a high glucose conversion yield of 92.4%. Furthermore, L. rhamnosus encapsulated in mesoporous silica-based material exhibited operational stability during repeated fermentation processes and no decrease in lactic acid production up to 8 repeated batches.

Journal of The Institute of Brewing, Nov 19, 2017

Brewer's spent grain (BSG) hydrolysates were used for L-(+)-lactic acid (LA) fermentation by Lact... more Brewer's spent grain (BSG) hydrolysates were used for L-(+)-lactic acid (LA) fermentation by Lactobacillus rhamnosus ATCC 7469. In this study the effect of the addition of various amounts of thin stillage (TS) in BSG hydrolysate on LA fermentation parameters were evaluated. TS addition significantly increased utilization of glucose by up to 43.0%. In batch fermentation the highest LA concentration and volumetric productivity of 31.0 g/L, and 0.93 g/L/h, respectively, were obtained with the addition of 50% TS. L. rhamnosus cell viability also increased with the addition of 50% TS (by 2.4%). TS addition significantly increased free amino nitrogen concentration (by up to 209%) which is important for bacterial growth. A strong positive correlation between free amino nitrogen and LA concentration was noted. Compared with the results obtained in the batch fermentation (50% TS), significantly higher LA concentration, yield and volumetric productivity (54.8, 1.9 and 4.0%, respectively) were achieved in fed-batch fermentation with glucose and TS addition. The results suggest that the combination of the by-products of brewing and bioethanol industries could be suitable for LA production.

Journal of The Institute of Brewing, Sep 6, 2017

Brewer's spent grain (BSG) hydrolysates were used for L-(+)-lactic acid (LA) fermentation by Lact... more Brewer's spent grain (BSG) hydrolysates were used for L-(+)-lactic acid (LA) fermentation by Lactobacillus rhamnosus ATCC 7469. The aim of this study was to evaluate fed-batch LA fermentation of BSG hydrolysate with the addition of glucose, glucose and yeast extract, and wort during LA fermentation and its effect on fermentation parameters such as LA concentration, its volumetric productivity and yield, and L. rhamnosus cell viability. The highest LA yield, volumetric productivity and concentration of 93.3%, 2.0 g/L/h, and 116.1 g/L, respectively, were achieved with glucose and yeast extract addition during fermentation. In fed-batch fermentation with glucose and yeast extract addition significantly higher LA concentration, yield and volumetric productivity (by 194.8; 2.2, and 20.7%, respectively) were achieved compared with batch fermentation. The results indicated that fed-batch fermentation could be used to increase LA fermentation efficiency.

World Academy of Science, Engineering and Technology, International Journal of Energy and Power Engineering, Apr 14, 2016

Biomass Conversion and Biorefinery, Aug 19, 2020

Fungal treatment of lignocellulose is an ecologically and economically acceptable method. However... more Fungal treatment of lignocellulose is an ecologically and economically acceptable method. However, it needs improvement to increase the hydrolysis rate. A novel combination of multiple response optimization of ligninolytic activity of Trametes hirsuta F13 and supplementation of the lignocellulosic substrate (beechwood sawdust) with sugar beet molasses stillage was employed to improve and manage the desired type of fungal ligninolytic activity leading to a significant enhancement of biomass saccharification. Obtained optimal cultivation conditions (molasses stillage concentration, 13%; substrate moisture, 63%; and temperature, 25°C) provided the desired combination of laccase and manganese-dependent peroxidase activity, and maintained the activities longer and at higher values (51.5 ± 3.5 U/L and 91 ± 4.24 U/L, respectively) than the conditions without molasses stillage (21.5 ± 2.12 U/L and 31.5 ± 4.9 U/L, respectively). Enzyme hydrolysis of the substrate treated for 7 days in the presence of molasses stillage released 20.54 ± 0.80 mg/mL fermentable sugars, and 63.58 ± 1.47 mg/mL from 18-days treated substrate, while sugar concentrations released from the substrates pretreated without the supplementation were 16.84 ± 0.30 mg/mL and 53.63 ± 2.16 mg/mL, respectively. The proposed new approach of the lignocellulose supplementation with sugar beet molasses stillage and manipulation and improvement of fungal ligninolytic activity proved to be a promising solution for the enhancement of lignocellulose bioconversion.

Journal on Processing and Energy in Agriculture, 2021

This research examined the potential use of isolated Serbian autochthonous fungi in lignocellulos... more This research examined the potential use of isolated Serbian autochthonous fungi in lignocellulosic biomass pretreatment. Among 12 isolated fungi, the isolates identified as Trametes hirsuta F13 and Stereum gausapatum F28 stood out as ligninolytic enzyme producers and were selected for potential use in the pretreatment of a waste lignocellulosic biomass. An isolate identified as Myrmaecium fulvopruinatum F14 showed high hydrolytic activity, but negligible ligninolytic activity, and it was selected as a potential producer of important industrial hydrolytic enzymes. Further, the breakdown of lignocellulosic waste, beechwood sawdust, by T. hirsuta F13 and S. gausapatum F28 was examined. Both isolates efficiently degraded biomass, but T. hirsuta F13 exhibited greater selectivity (selectivity coefficient of 1.7) than S. gausapatum F28 (1.1). The isolate F13 was considered a better candidate for the pretreatment, and it was selected for further analysis which involved the use of molasses stillage as a supplement to improve the pretreatment.

The suitability of selected ZP maize hybrids for bioethanol and starch production was studied. Th... more The suitability of selected ZP maize hybrids for bioethanol and starch production was studied. The composition, physical and chemical traits, and the alcoholic fermentation of the maize hybrids hydrolysates were studied using Saccharomyces cerevisiae var. ellipsoideus yeast. The hybrid ZP 434 achieved the highest ethanol yield of 90.2% of the theoretical yield after 34 hr of fermentation, the maximum yield of 65.16%, and starch recovery of 93.14%. The hybrid ZP 544 obtained the lowest ethanol yield of 69.32%. The similar ethanol yield (approximately 79%) was also detected in Hybrids ZP 704wx and ZP 341 obtained similar ethanol yield of ≈ 79%, but differed very much on their starch content. The highest (74.13%) and the lowest (69%) starch contents were determined in hybrids ZP 704wx and ZP 341, respectively. This is an abstract of a paper presented at the 19th International Congress of Chemical and Process Engineering and 7th European Congress of Chemical Engineering (Prague, Czech Republic 8/28/2010-9/1/2010)

Food Technology and Biotechnology, 2018

Environmental Science and Pollution Research, 2019

This paper presents results of studies on qualities of maize dried distillers' grains with so... more This paper presents results of studies on qualities of maize dried distillers' grains with solubles (DDGS), as animal feed, which is a by-product from the process of maize grain-based bioethanol production. Twenty maize hybrids, developed at the Maize Research Institute, Zemun Polje, were used in this study. The moisture content in all DDGS samples was below 13%-the maximum value according to the Serbian Regulation. Furthermore, obtained results show that all observed DDGS samples had a high content of protein (29.58-36.08%), i.e. threefold higher than in the initial raw material-maize grain. The digestibility of dry matter in samples of DDGS ranged from 74.09 (ZP Rumenka) to 82.41% (ZP 505). Based on obtained results, samples of DDGS were of high quality and therefore can be used as feed for the preparation of complete and concentrated feed. Key words: maize, dried distillers' grains with solubles (DDGS), animal feed, bioethanol. REZIME Proizvodnjom bioetanola od zrna kukur...

Fuel, Apr 1, 2021

Lignite coal fly ash (FA) from a domestic thermal power plant was converted into a pure cancrinit... more Lignite coal fly ash (FA) from a domestic thermal power plant was converted into a pure cancrinite zeolitic material (ZM FA) using a novel, custom-made, rotating autoclave reactor system by a short-term alkali activation process. The obtained ZM FA was used as catalyst support of calcium oxide as an active component derived from waste chicken eggshells (ES). The ZM FA supported calcium oxide catalyst (xCaO/ZM FA) was synthesized by means of the ultrasound-assisted method. The influence of different concentrations of dispersed calcium oxide (x = 5-20 wt%) over ZM FA and thermal treatment at different temperatures (450-600 • C) were studied. The structural and morphological characterization showed that the original cancrinite structure was preserved. The basicity and textural properties indicated the presence of strong active sites in a well-defined pore network suitable for the reactions of bulky organic compounds such as triacylglycerols (TAGs). The highest activity (96.5% of fatty acid methyl esters) in the methanolysis of sunflower oil was achieved with the 20CaO/ZM FA catalyst under reaction conditions: temperature of 60 • C, methanol/oil molar ratio of 12:1, catalyst concentration of 4 wt%, and reaction time of 2 h. It was found that the optimal calcination temperature of the catalyst precursor was 550 • C. At calcination temperatures above 550 • C, the melting of the glassy phase became more intense whereby the molten phase partially reacted with calcium oxide forming the catalytically inactive calcium silicate compounds (wollastonite, larnite, etc.). The rate constants of the two tested kinetic models were correlated with the concentrations of active calcium oxide. The MRPD of both models was low indicating their reliability.

Developments in food science, 1992

SUMMARY Regiospecific interesterification of triacylglycerols of palm oil mid fraction with stear... more SUMMARY Regiospecific interesterification of triacylglycerols of palm oil mid fraction with stearic acid by lipase from Rhizopus arrhizus immobilized on inorganic support was studied, for the purpose of cocoa buter-like fat production. Addition of 5% of crude soybean lechitin on the mass of immobilized enzyme caused valuable increase of stearic acid content in interesterified triacylglycerols. It is considered that lechitin acts as a surface active agent and forms reverse micellar system arround immobilized and hydrated enzyme in n-hexane.

Journal of bioscience and bioengineering, Jan 20, 2016

Lactic acid bacteria immobilization methods have been widely used for lactic acid production. Unt... more Lactic acid bacteria immobilization methods have been widely used for lactic acid production. Until now, the most common immobilization matrix used is calcium alginate. However, Ca-alginate gel disintegrated during lactic acid fermentation. To overcome this deficiency, we developed an immobilization method in which Lactobacillus rhamnosus cells were successfully encapsulated into an ordered mesoporous silica-based material under mild conditions with a high immobilization efficiency of 78.77% by using elemental analysis. We also optimized the cultivation conditions of the immobilized L. rhamnosus and obtained a high glucose conversion yield of 92.4%. Furthermore, L. rhamnosus encapsulated in mesoporous silica-based material exhibited operational stability during repeated fermentation processes and no decrease in lactic acid production up to 8 repeated batches.

Journal of The Institute of Brewing, Nov 19, 2017

Brewer's spent grain (BSG) hydrolysates were used for L-(+)-lactic acid (LA) fermentation by Lact... more Brewer's spent grain (BSG) hydrolysates were used for L-(+)-lactic acid (LA) fermentation by Lactobacillus rhamnosus ATCC 7469. In this study the effect of the addition of various amounts of thin stillage (TS) in BSG hydrolysate on LA fermentation parameters were evaluated. TS addition significantly increased utilization of glucose by up to 43.0%. In batch fermentation the highest LA concentration and volumetric productivity of 31.0 g/L, and 0.93 g/L/h, respectively, were obtained with the addition of 50% TS. L. rhamnosus cell viability also increased with the addition of 50% TS (by 2.4%). TS addition significantly increased free amino nitrogen concentration (by up to 209%) which is important for bacterial growth. A strong positive correlation between free amino nitrogen and LA concentration was noted. Compared with the results obtained in the batch fermentation (50% TS), significantly higher LA concentration, yield and volumetric productivity (54.8, 1.9 and 4.0%, respectively) were achieved in fed-batch fermentation with glucose and TS addition. The results suggest that the combination of the by-products of brewing and bioethanol industries could be suitable for LA production.

Journal of The Institute of Brewing, Sep 6, 2017

Brewer's spent grain (BSG) hydrolysates were used for L-(+)-lactic acid (LA) fermentation by Lact... more Brewer's spent grain (BSG) hydrolysates were used for L-(+)-lactic acid (LA) fermentation by Lactobacillus rhamnosus ATCC 7469. The aim of this study was to evaluate fed-batch LA fermentation of BSG hydrolysate with the addition of glucose, glucose and yeast extract, and wort during LA fermentation and its effect on fermentation parameters such as LA concentration, its volumetric productivity and yield, and L. rhamnosus cell viability. The highest LA yield, volumetric productivity and concentration of 93.3%, 2.0 g/L/h, and 116.1 g/L, respectively, were achieved with glucose and yeast extract addition during fermentation. In fed-batch fermentation with glucose and yeast extract addition significantly higher LA concentration, yield and volumetric productivity (by 194.8; 2.2, and 20.7%, respectively) were achieved compared with batch fermentation. The results indicated that fed-batch fermentation could be used to increase LA fermentation efficiency.

World Academy of Science, Engineering and Technology, International Journal of Energy and Power Engineering, Apr 14, 2016

Biomass Conversion and Biorefinery, Aug 19, 2020

Fungal treatment of lignocellulose is an ecologically and economically acceptable method. However... more Fungal treatment of lignocellulose is an ecologically and economically acceptable method. However, it needs improvement to increase the hydrolysis rate. A novel combination of multiple response optimization of ligninolytic activity of Trametes hirsuta F13 and supplementation of the lignocellulosic substrate (beechwood sawdust) with sugar beet molasses stillage was employed to improve and manage the desired type of fungal ligninolytic activity leading to a significant enhancement of biomass saccharification. Obtained optimal cultivation conditions (molasses stillage concentration, 13%; substrate moisture, 63%; and temperature, 25°C) provided the desired combination of laccase and manganese-dependent peroxidase activity, and maintained the activities longer and at higher values (51.5 ± 3.5 U/L and 91 ± 4.24 U/L, respectively) than the conditions without molasses stillage (21.5 ± 2.12 U/L and 31.5 ± 4.9 U/L, respectively). Enzyme hydrolysis of the substrate treated for 7 days in the presence of molasses stillage released 20.54 ± 0.80 mg/mL fermentable sugars, and 63.58 ± 1.47 mg/mL from 18-days treated substrate, while sugar concentrations released from the substrates pretreated without the supplementation were 16.84 ± 0.30 mg/mL and 53.63 ± 2.16 mg/mL, respectively. The proposed new approach of the lignocellulose supplementation with sugar beet molasses stillage and manipulation and improvement of fungal ligninolytic activity proved to be a promising solution for the enhancement of lignocellulose bioconversion.

Journal on Processing and Energy in Agriculture, 2021

This research examined the potential use of isolated Serbian autochthonous fungi in lignocellulos... more This research examined the potential use of isolated Serbian autochthonous fungi in lignocellulosic biomass pretreatment. Among 12 isolated fungi, the isolates identified as Trametes hirsuta F13 and Stereum gausapatum F28 stood out as ligninolytic enzyme producers and were selected for potential use in the pretreatment of a waste lignocellulosic biomass. An isolate identified as Myrmaecium fulvopruinatum F14 showed high hydrolytic activity, but negligible ligninolytic activity, and it was selected as a potential producer of important industrial hydrolytic enzymes. Further, the breakdown of lignocellulosic waste, beechwood sawdust, by T. hirsuta F13 and S. gausapatum F28 was examined. Both isolates efficiently degraded biomass, but T. hirsuta F13 exhibited greater selectivity (selectivity coefficient of 1.7) than S. gausapatum F28 (1.1). The isolate F13 was considered a better candidate for the pretreatment, and it was selected for further analysis which involved the use of molasses stillage as a supplement to improve the pretreatment.

The suitability of selected ZP maize hybrids for bioethanol and starch production was studied. Th... more The suitability of selected ZP maize hybrids for bioethanol and starch production was studied. The composition, physical and chemical traits, and the alcoholic fermentation of the maize hybrids hydrolysates were studied using Saccharomyces cerevisiae var. ellipsoideus yeast. The hybrid ZP 434 achieved the highest ethanol yield of 90.2% of the theoretical yield after 34 hr of fermentation, the maximum yield of 65.16%, and starch recovery of 93.14%. The hybrid ZP 544 obtained the lowest ethanol yield of 69.32%. The similar ethanol yield (approximately 79%) was also detected in Hybrids ZP 704wx and ZP 341 obtained similar ethanol yield of ≈ 79%, but differed very much on their starch content. The highest (74.13%) and the lowest (69%) starch contents were determined in hybrids ZP 704wx and ZP 341, respectively. This is an abstract of a paper presented at the 19th International Congress of Chemical and Process Engineering and 7th European Congress of Chemical Engineering (Prague, Czech Republic 8/28/2010-9/1/2010)

Food Technology and Biotechnology, 2018

Environmental Science and Pollution Research, 2019

This paper presents results of studies on qualities of maize dried distillers' grains with so... more This paper presents results of studies on qualities of maize dried distillers' grains with solubles (DDGS), as animal feed, which is a by-product from the process of maize grain-based bioethanol production. Twenty maize hybrids, developed at the Maize Research Institute, Zemun Polje, were used in this study. The moisture content in all DDGS samples was below 13%-the maximum value according to the Serbian Regulation. Furthermore, obtained results show that all observed DDGS samples had a high content of protein (29.58-36.08%), i.e. threefold higher than in the initial raw material-maize grain. The digestibility of dry matter in samples of DDGS ranged from 74.09 (ZP Rumenka) to 82.41% (ZP 505). Based on obtained results, samples of DDGS were of high quality and therefore can be used as feed for the preparation of complete and concentrated feed. Key words: maize, dried distillers' grains with solubles (DDGS), animal feed, bioethanol. REZIME Proizvodnjom bioetanola od zrna kukur...

Fuel, Apr 1, 2021

Lignite coal fly ash (FA) from a domestic thermal power plant was converted into a pure cancrinit... more Lignite coal fly ash (FA) from a domestic thermal power plant was converted into a pure cancrinite zeolitic material (ZM FA) using a novel, custom-made, rotating autoclave reactor system by a short-term alkali activation process. The obtained ZM FA was used as catalyst support of calcium oxide as an active component derived from waste chicken eggshells (ES). The ZM FA supported calcium oxide catalyst (xCaO/ZM FA) was synthesized by means of the ultrasound-assisted method. The influence of different concentrations of dispersed calcium oxide (x = 5-20 wt%) over ZM FA and thermal treatment at different temperatures (450-600 • C) were studied. The structural and morphological characterization showed that the original cancrinite structure was preserved. The basicity and textural properties indicated the presence of strong active sites in a well-defined pore network suitable for the reactions of bulky organic compounds such as triacylglycerols (TAGs). The highest activity (96.5% of fatty acid methyl esters) in the methanolysis of sunflower oil was achieved with the 20CaO/ZM FA catalyst under reaction conditions: temperature of 60 • C, methanol/oil molar ratio of 12:1, catalyst concentration of 4 wt%, and reaction time of 2 h. It was found that the optimal calcination temperature of the catalyst precursor was 550 • C. At calcination temperatures above 550 • C, the melting of the glassy phase became more intense whereby the molten phase partially reacted with calcium oxide forming the catalytically inactive calcium silicate compounds (wollastonite, larnite, etc.). The rate constants of the two tested kinetic models were correlated with the concentrations of active calcium oxide. The MRPD of both models was low indicating their reliability.