maria kanellaki | Technological Educational Institute (TEI) of Western Greece (former TEI of Patras) (original) (raw)
Papers by maria kanellaki
Bioresource Technology, 2015
An economic evaluation of an integrated technology for industrial scale new generation biofuel pr... more An economic evaluation of an integrated technology for industrial scale new generation biofuel production using whey, vinasse, and lignocellulosic biomass as raw materials is reported. Anaerobic packed-bed bioreactors were used for organic acids production using initially synthetic media and then wastes. Butyric, lactic and acetic acid were predominately produced from vinasse, whey, and cellulose, respectively. Mass balance was calculated for a 16,000L daily production capacity. Liquid-liquid extraction was applied for recovery of the organic acids using butanol-1 as an effective extraction solvent which serves also as the alcohol for the subsequent enzyme-catalyzed esterification. The investment needed for the installation of the factory was estimated to about 1.7million€ with depreciation excepted at about 3months. For cellulosics, the installation investment was estimated to be about 7-fold higher with depreciation at about 1.5years. The proposed technology is an alternative trend in biofuel production.
Biotechnology for Biofuels, 2015
Background: This investigation comprises a contribution on the production of a new generation bio... more Background: This investigation comprises a contribution on the production of a new generation biofuel using the industrial liquid waste of bioethanol distilleries, known as vinasse. This study focuses on the exploitation of vinasse as an acidogenesis substrate for volatile fatty acids and simultaneous ethanol production. These products can be used for ester production, which is the new generation biofuel. Therefore, the aims of the present study are (i) to examine any promotional effect of γ-alumina on acidogenesis of a sucrose-raffinose mixture simulating vinasse, (ii) to study the operational stability of the continuous acidogenesis of sucrose and raffinose and subsequently of vinasse, and (iii) to determine the volatile fatty acid chemical composition and ethanol formation. Results: Batch acidogenesis of sucrose and raffinose mixtures showed that γ-alumina promoted fermentation leading to an increase in the volatile fatty acid yield factor from 40% to 95% compared to free cells. The application of the system in continuous mode for more than 3 months showed that the continuous volatile fatty acid productivity obtained was higher than 7 g/L/day. Lactic acid was the predominant acid when sucrose and raffinose were used while butyric acid in the case of vinasse. The highest volatile fatty acid concentration reached was 19 g/L for vinasse. Conclusions: A promoting effect of γ-alumina in acidogenic fermentation of sucrose-raffinose and vinasse is reported. Continuous acidogenesis of sucrose-raffinose mixtures and vinasse using γ-alumina with immobilized cells showed high operational stability (more than 3 months). These findings result in easy scale up of the process that will produce a high annual added value of $11,000,000 in a daily bioethanol production plant of 50,000 L.
Bioresource Technology, 2015
The use of kissiris as promoter (culture immobilization carrier) in anaerobic acidogenesis of suc... more The use of kissiris as promoter (culture immobilization carrier) in anaerobic acidogenesis of sucrose, raffinose and vinasse is reported. Initially, the effect of pH (4-8) and fermentation temperature (18-52°C) on the accumulation of low molecular weight organic acids (OAs) during sucrose acidogenesis, was evaluated. The promoting effect of kissiris was confirmed compared to free cells, resulting in 80% increased OAs production. The optimum conditions (pH 8; 37°C) were used during acidogenesis of sucrose/raffinose mixtures. A continuous system was also operated for more than 2months. When sucrose and sucrose/raffinose mixtures were used, lactic acid type fermentation prevailed, while when vinasse was used, butyric acid type fermentation occurred. Total OAs concentrations were more than 14g/L and ethanol concentrations were 0.5-1mL/L. Culture adaptation in vinasse was necessary to avoid poor results. The proposed process is promising for new generation ester-based biofuel production from industrial wastes.
Bioresource Technology, 2015
An economic evaluation of an integrated technology for industrial scale new generation biofuel pr... more An economic evaluation of an integrated technology for industrial scale new generation biofuel production using whey, vinasse, and lignocellulosic biomass as raw materials is reported. Anaerobic packed-bed bioreactors were used for organic acids production using initially synthetic media and then wastes. Butyric, lactic and acetic acid were predominately produced from vinasse, whey, and cellulose, respectively. Mass balance was calculated for a 16,000L daily production capacity. Liquid-liquid extraction was applied for recovery of the organic acids using butanol-1 as an effective extraction solvent which serves also as the alcohol for the subsequent enzyme-catalyzed esterification. The investment needed for the installation of the factory was estimated to about 1.7million€ with depreciation excepted at about 3months. For cellulosics, the installation investment was estimated to be about 7-fold higher with depreciation at about 1.5years. The proposed technology is an alternative trend in biofuel production.
Biotechnology for Biofuels, 2015
Background: This investigation comprises a contribution on the production of a new generation bio... more Background: This investigation comprises a contribution on the production of a new generation biofuel using the industrial liquid waste of bioethanol distilleries, known as vinasse. This study focuses on the exploitation of vinasse as an acidogenesis substrate for volatile fatty acids and simultaneous ethanol production. These products can be used for ester production, which is the new generation biofuel. Therefore, the aims of the present study are (i) to examine any promotional effect of γ-alumina on acidogenesis of a sucrose-raffinose mixture simulating vinasse, (ii) to study the operational stability of the continuous acidogenesis of sucrose and raffinose and subsequently of vinasse, and (iii) to determine the volatile fatty acid chemical composition and ethanol formation.
Food Chemistry, 2015
The objective of this study was to produce a composite biocatalyst, based on porous cellulosic ma... more The objective of this study was to produce a composite biocatalyst, based on porous cellulosic material, produced after wood sawdust delignification (tubular cellulose; TC) and starch gel (SG), for the development of bioprocesses related to enzyme applications. The composite biocatalyst was studied by Scanning Electron Microscopy to observe the SG deposition in the TC pores, and porosimetry analysis to determine the average pore diameter and surface area. The deposition of SG into the TC tubes provided a TC/SG composite with reduced pore sizes. X-ray powder diffractometry showed a decrease of crystallinity with increased SG ratio in the composite. The composite was used as an insoluble carrier for entrapment of the dairy enzyme rennin, leading to the production of an active biocatalyst for milk coagulation (initiation of milk clotting at about 20 min and full coagulation at about 200 min), creating perspectives for several applications in food enzyme research and technology.
Food chemistry, 2015
The effect of the amount of immobilized Lactobacillus casei ATCC 393 on wheat grains on the gener... more The effect of the amount of immobilized Lactobacillus casei ATCC 393 on wheat grains on the generation of volatile compounds during the production of heat treated probiotic dry-fermented sausages was investigated. For comparison reasons, sausages containing free L. casei cells or no starter culture as well as a similar commercial product were also included in the study. Samples ripened for 8days and heat treated to 70-72°C for 8-10min were subjected to Solid Phase Microextraction (SPME) Gas Chromatography/Mass Spectrometry (GC/MS) analysis. The starter culture affected significantly the production of volatile compounds. The highest content of esters and alcohols was observed in the sample containing 30g of immobilized cells/kg of stuffing mixture, while the highest concentration of organic acids was observed in the sausages with no starter culture. In contrast, the commercial product contained the lowest concentration of volatiles. Principal component analysis of the semi-quantitati...
Meat science, 2015
The effect of immobilized Lactobacillus casei ATCC 393 on wheat grains on the generation of volat... more The effect of immobilized Lactobacillus casei ATCC 393 on wheat grains on the generation of volatile compounds in probiotic dry-fermented sausages during ripening was investigated. For comparison reasons, sausages containing free L. casei cells or no starter culture were also included in the study. Samples were collected after 1, 28 and 45days of ripening and subjected to SPME GC/MS analysis. Both the probiotic culture and the ripening process affected significantly the concentration of all volatile compounds. The significantly highest content of total volatiles, esters, alcohols and miscellaneous compounds was observed in sausages containing the highest amount of immobilized culture (300g/kg of stuffing mixture) ripened for 45days. Principal component analysis of the semi-quantitative data revealed that primarily the concentration of the immobilized probiotic culture affected the volatile composition.
Enzyme and microbial technology, 2014
Advantages in maltose fermentation at extremely low temperatures (5-10°C) using an alcohol resist... more Advantages in maltose fermentation at extremely low temperatures (5-10°C) using an alcohol resistant and cryotolerant yeast strain (Saccharomyces cerevisiae AXAZ-1) immobilized on porous cellulosic material (or tubular cellulose, TC), produced by delignification of wood sawdust, are reported. Pure maltose and glucose media (80, 100 and 140 g/l) were examined as model substrates to evaluate the potential effect of TC on the rate of fermentation of maltose containing substrates. The use of TC sharply accelerated the rate of maltose fermentation compared to free cells (FC) in suspension. Fermentation at 5°C by immobilized cells was complete, while FC were unable to ferment maltose at this temperature, in contrast to glucose, which was completely fermented. From the results of maltose and glucose fermentations at 5 and 10°C, it was concluded that the effect of TC was higher at lower fermentation temperature and that its promotional effect on fermentation rate had to be at the step of ma...
Bioresource Technology, 2015
The use of kissiris as promoter (culture immobilization carrier) in anaerobic acidogenesis of suc... more The use of kissiris as promoter (culture immobilization carrier) in anaerobic acidogenesis of sucrose, raffinose and vinasse is reported. Initially, the effect of pH (4-8) and fermentation temperature (18-52°C) on the accumulation of low molecular weight organic acids (OAs) during sucrose acidogenesis, was evaluated. The promoting effect of kissiris was confirmed compared to free cells, resulting in 80% increased OAs production. The optimum conditions (pH 8; 37°C) were used during acidogenesis of sucrose/raffinose mixtures. A continuous system was also operated for more than 2months. When sucrose and sucrose/raffinose mixtures were used, lactic acid type fermentation prevailed, while when vinasse was used, butyric acid type fermentation occurred. Total OAs concentrations were more than 14g/L and ethanol concentrations were 0.5-1mL/L. Culture adaptation in vinasse was necessary to avoid poor results. The proposed process is promising for new generation ester-based biofuel production from industrial wastes.
Journal of Food Science and Technology, 2014
Resin from Pistacia terebinthus tree was used for the immobilization of L. casei ATCC 393 cells. ... more Resin from Pistacia terebinthus tree was used for the immobilization of L. casei ATCC 393 cells. The encapsulated L. casei cells biocatalysts were added as adjuncts during yogurt production at 45°C and probiotic viability was assessed during storage at 4°C. For comparison reasons yogurt with free L. casei cells were prepared. The effect of encapsulated bacteria as adjuncts in yogurt on pH, lactic acid, lactose and other physicochemical parameters were studied for 60 storage days at 4°C. Samples were also tested for the microbiological and organoleptic characteristics during storage at 4°C. Encapsulation matrix seems to sustain the viability of embedded L. casei cells at levels more than 7 logcfug −1 after 60 days of storage at 4°C. Furthermore, the absence of p a t h o g e n s s u c h a s S a l m o n e l l a , S t a p h y l o c o c c i , Enterobacteriaceae and coliforms in the produced yogurts is noteworthy where spoilage microorganisms such as yeasts and molds seem to affect yogurt quality only in absence of Pistacia terebinthus resin. The effect of the resin on production of aroma-related compounds responsible for yogurt flavor was also studied using the solid phase microextraction gas chromatography/mass spectrometry technique. Alpha and beta-pinene were the major aroma compounds detected in produced yogurts (over 60 % of total aromatic compounds detected). Yogurts with immobilized cells on P.terebintus resin had a fine aroma and taste characteristic of the resin.
Process Biochemistry, 2003
Glycerol formation is reported in alcoholic fermentation with an alcohol resistant and psychrophy... more Glycerol formation is reported in alcoholic fermentation with an alcohol resistant and psychrophylic Saccharomyces cerevisiae strain immobilized on delignified cellulosic material (DCM) and gluten pellets (GP). The immobilized biocatalysts were used for successive fermentation batches of synthetic media (glucose, fructose and sucrose) and grape must. Generally, immobilization affects glycerol production positively. Glycerol concentration in the range 11.9 Á/14.9 g/l in wines was produced by immobilized cells and 10.2 Á/12.8 g/l was produced by free cells at fermentation temperatures 5 Á/30 8C. Glycerol concentration was affected by fermentation temperature and decreased as the temperature decreased for every fermenting medium. Glycerol concentration was higher in fermentations of grape must with immobilized or free cells than in those of synthetic media. The increased glycerol concentrations produced by immobilized yeast cells on DCM and GP support their use in wine making given that glycerol affects wine flavour and gives an impression of fullness and softness.
Journal of the Science of Food and Agriculture, 2005
... Correspondence: Athanasios A Koutinas, Food ... 15 Argiriou T, Kanellaki M, Voliotis S and Ko... more ... Correspondence: Athanasios A Koutinas, Food ... 15 Argiriou T, Kanellaki M, Voliotis S and Koutinas AA, Kissiris-supported yeast cells: high biocatalytic stability and productivity improvement by successive preservations at 0 °C. J Agric Food Chem 44: 40284031 (1996). ...
Journal of Food Engineering, 2009
A freeze-dried immobilized biocatalyst produced by immobilization of Saccharomyces cerevisiae AXA... more A freeze-dried immobilized biocatalyst produced by immobilization of Saccharomyces cerevisiae AXAZ-1 yeast cells on gluten pellets and subsequent freeze-drying was used in a multistage fixed-bed tower (MFBT) bioreactor for batch and continuous wine-making. The MFBT bioreactor resulted in higher alcohol productivity compared to fermentations carried out in a packed bed (PB) bioreactor and showed an important operational stability and no decrease in activity, even at low fermentation temperature (5°C) and after storage for 6 months at 4°C. The production of amyl alcohols proved to be temperature dependent and was significantly reduced at low temperatures. Re-activation of the freeze-dried immobilized cells after storage for 6 months resulted in further decreased content of amyl alcohols. The SPME GC/MS analysis of volatile compounds revealed no significant differences in the wines produced by MFBT and PB bioreactors, while the preliminary sensory evaluation ascertained the overall improved quality of the produced wines. Potential industrial application of MFBT bioreactor is also assessed and discussed.
Journal of Agricultural and Food Chemistry, 2005
In this work Lactobacillus casei ATCC 393 cells immobilized on delignified cellulosic material (D... more In this work Lactobacillus casei ATCC 393 cells immobilized on delignified cellulosic material (DCM) were used for malolactic fermentation (MLF) of wine. Wine was produced using yeast cells immobilized on DCM at 20 degrees C, and after alcoholic fermentation, MLF at 27 degrees C followed using immobilized L. casei ATCC 393 cells. A total of 11 repeated alcoholic and subsequent MLF batches were performed within a period of 1 month. As the repeated MLF batches proceeded, the MLF activity of the immobilized biocatalyst was reduced. Malic acid degradation was reduced from 80 to 2%, pH was reduced by 0.5-0.1 unit, acetic acid concentrations were slightly reduced or remained stable (0.002 g/L), the higher alcohols 1-propanol, isobutyl alcohol, and amyl alcohol were decreased by 84, 23, and 11%, respectively, and ethyl acetate concentration was increased by approximately 56%. Wine samples were analyzed by GC-MS before and after MLF, revealing some qualitative differences.
Journal of Agricultural and Food Chemistry, 2003
A biocatalyst was prepared by immobilization of Saccharomyces cerevisiae cells on grape skins. Re... more A biocatalyst was prepared by immobilization of Saccharomyces cerevisiae cells on grape skins. Repeated batch fermentations were conducted using this biocatalyst as well as free cells, at 25, 20, 15, and 10 degrees C. Solid phase microextraction (SPME) was used in monitoring the evolution of volatile byproducts. The effect of immobilization and temperature on evolution patterns of volatiles was obvious. The major part of esters was formed after consumption of 40-50% of the sugars. Similar processes were observed for amyl alcohols and 2-phenylethanol, whereas 1-propanol and 2-methyl-1-propanol were formed during the whole alcoholic fermentation period at an almost constant formation rate. Acetaldehyde and acetoin were synthesized in the early stages of fermentation. Afterward, their amount decreased. In most cases, immobilized cells exhibited higher formation rates of volatiles than free cells. The final concentration of esters was higher in wines produced by immobilized biocatalyst. Their amount increased with temperature decrease. The opposite was observed for higher alcohols.
Food Chemistry, 2007
A biocatalyst, prepared by immobilization of the psychrotolerant yeast strain Saccharomyces cerev... more A biocatalyst, prepared by immobilization of the psychrotolerant yeast strain Saccharomyces cerevisiae AXAZ-1 on delignified brewer’s spent grains, was used for brewing at very low temperatures, resulting in beers with fine clarity, excellent quality and mature character after the end of primary fermentation. Fermentation times were low (only 20 days at 0°C), while ethanol and beer productivities were high, showing
Enzyme and Microbial Technology, 2007
Industrial scale-up of whey fermentation, promoted by raisin extracts, using free kefir-yeast cel... more Industrial scale-up of whey fermentation, promoted by raisin extracts, using free kefir-yeast cells is reported. The fermented whey would be exploited as raw material to produce kefir-like whey-based drinks, potable and fuel alcohol, as well as kefir-yeast biomass for use as baker's yeast. The scale-up process involved the development of a technology transfer scheme from lab-scale experiments to a successive series of increased capacity bioreactors (100, 3000 and 11,000 L). The development of this technology was supported by the six-fold promotion of whey fermentation by the addition of 1% black raisin extracts (optimum concentration found in this investigation), as well as by the formation of kefir-yeast in the form of easily precipitated granular biomass that led to the avoidance of centrifugal separators, which are equipment of high cost. A cost analysis showed a big reduction of the production cost of the aforementioned products in comparison with the market prices, attributed to the negligible cost of raw materials (whey) and the granular biomass formation.
Bioresource Technology, 2014
h i g h l i g h t s Contribution on a new generation biofuel based on VFAs production by acidogen... more h i g h l i g h t s Contribution on a new generation biofuel based on VFAs production by acidogenic fermentation. Acidogenic fermentation of glucose advantaged by immobilised cells on c-alumina. Higher VFA yields obtained at substrate concentrations lower than 50 g glucose/L using immobilised cells. Butyric-type fermentation enhanced by continuous operation at high pH (9) using immobilised cells.
Bioresource Technology, 2014
h i g h l i g h t s Porous cellulosic materials and composites for cell immobilisation. Improveme... more h i g h l i g h t s Porous cellulosic materials and composites for cell immobilisation. Improvements in lactic acid fermentation by immobilised L. bulgaricus cells. Possible use of the three-layer composites for multispecies co-immobilisation.
Bioresource Technology, 2015
An economic evaluation of an integrated technology for industrial scale new generation biofuel pr... more An economic evaluation of an integrated technology for industrial scale new generation biofuel production using whey, vinasse, and lignocellulosic biomass as raw materials is reported. Anaerobic packed-bed bioreactors were used for organic acids production using initially synthetic media and then wastes. Butyric, lactic and acetic acid were predominately produced from vinasse, whey, and cellulose, respectively. Mass balance was calculated for a 16,000L daily production capacity. Liquid-liquid extraction was applied for recovery of the organic acids using butanol-1 as an effective extraction solvent which serves also as the alcohol for the subsequent enzyme-catalyzed esterification. The investment needed for the installation of the factory was estimated to about 1.7million€ with depreciation excepted at about 3months. For cellulosics, the installation investment was estimated to be about 7-fold higher with depreciation at about 1.5years. The proposed technology is an alternative trend in biofuel production.
Biotechnology for Biofuels, 2015
Background: This investigation comprises a contribution on the production of a new generation bio... more Background: This investigation comprises a contribution on the production of a new generation biofuel using the industrial liquid waste of bioethanol distilleries, known as vinasse. This study focuses on the exploitation of vinasse as an acidogenesis substrate for volatile fatty acids and simultaneous ethanol production. These products can be used for ester production, which is the new generation biofuel. Therefore, the aims of the present study are (i) to examine any promotional effect of γ-alumina on acidogenesis of a sucrose-raffinose mixture simulating vinasse, (ii) to study the operational stability of the continuous acidogenesis of sucrose and raffinose and subsequently of vinasse, and (iii) to determine the volatile fatty acid chemical composition and ethanol formation. Results: Batch acidogenesis of sucrose and raffinose mixtures showed that γ-alumina promoted fermentation leading to an increase in the volatile fatty acid yield factor from 40% to 95% compared to free cells. The application of the system in continuous mode for more than 3 months showed that the continuous volatile fatty acid productivity obtained was higher than 7 g/L/day. Lactic acid was the predominant acid when sucrose and raffinose were used while butyric acid in the case of vinasse. The highest volatile fatty acid concentration reached was 19 g/L for vinasse. Conclusions: A promoting effect of γ-alumina in acidogenic fermentation of sucrose-raffinose and vinasse is reported. Continuous acidogenesis of sucrose-raffinose mixtures and vinasse using γ-alumina with immobilized cells showed high operational stability (more than 3 months). These findings result in easy scale up of the process that will produce a high annual added value of $11,000,000 in a daily bioethanol production plant of 50,000 L.
Bioresource Technology, 2015
The use of kissiris as promoter (culture immobilization carrier) in anaerobic acidogenesis of suc... more The use of kissiris as promoter (culture immobilization carrier) in anaerobic acidogenesis of sucrose, raffinose and vinasse is reported. Initially, the effect of pH (4-8) and fermentation temperature (18-52°C) on the accumulation of low molecular weight organic acids (OAs) during sucrose acidogenesis, was evaluated. The promoting effect of kissiris was confirmed compared to free cells, resulting in 80% increased OAs production. The optimum conditions (pH 8; 37°C) were used during acidogenesis of sucrose/raffinose mixtures. A continuous system was also operated for more than 2months. When sucrose and sucrose/raffinose mixtures were used, lactic acid type fermentation prevailed, while when vinasse was used, butyric acid type fermentation occurred. Total OAs concentrations were more than 14g/L and ethanol concentrations were 0.5-1mL/L. Culture adaptation in vinasse was necessary to avoid poor results. The proposed process is promising for new generation ester-based biofuel production from industrial wastes.
Bioresource Technology, 2015
An economic evaluation of an integrated technology for industrial scale new generation biofuel pr... more An economic evaluation of an integrated technology for industrial scale new generation biofuel production using whey, vinasse, and lignocellulosic biomass as raw materials is reported. Anaerobic packed-bed bioreactors were used for organic acids production using initially synthetic media and then wastes. Butyric, lactic and acetic acid were predominately produced from vinasse, whey, and cellulose, respectively. Mass balance was calculated for a 16,000L daily production capacity. Liquid-liquid extraction was applied for recovery of the organic acids using butanol-1 as an effective extraction solvent which serves also as the alcohol for the subsequent enzyme-catalyzed esterification. The investment needed for the installation of the factory was estimated to about 1.7million€ with depreciation excepted at about 3months. For cellulosics, the installation investment was estimated to be about 7-fold higher with depreciation at about 1.5years. The proposed technology is an alternative trend in biofuel production.
Biotechnology for Biofuels, 2015
Background: This investigation comprises a contribution on the production of a new generation bio... more Background: This investigation comprises a contribution on the production of a new generation biofuel using the industrial liquid waste of bioethanol distilleries, known as vinasse. This study focuses on the exploitation of vinasse as an acidogenesis substrate for volatile fatty acids and simultaneous ethanol production. These products can be used for ester production, which is the new generation biofuel. Therefore, the aims of the present study are (i) to examine any promotional effect of γ-alumina on acidogenesis of a sucrose-raffinose mixture simulating vinasse, (ii) to study the operational stability of the continuous acidogenesis of sucrose and raffinose and subsequently of vinasse, and (iii) to determine the volatile fatty acid chemical composition and ethanol formation.
Food Chemistry, 2015
The objective of this study was to produce a composite biocatalyst, based on porous cellulosic ma... more The objective of this study was to produce a composite biocatalyst, based on porous cellulosic material, produced after wood sawdust delignification (tubular cellulose; TC) and starch gel (SG), for the development of bioprocesses related to enzyme applications. The composite biocatalyst was studied by Scanning Electron Microscopy to observe the SG deposition in the TC pores, and porosimetry analysis to determine the average pore diameter and surface area. The deposition of SG into the TC tubes provided a TC/SG composite with reduced pore sizes. X-ray powder diffractometry showed a decrease of crystallinity with increased SG ratio in the composite. The composite was used as an insoluble carrier for entrapment of the dairy enzyme rennin, leading to the production of an active biocatalyst for milk coagulation (initiation of milk clotting at about 20 min and full coagulation at about 200 min), creating perspectives for several applications in food enzyme research and technology.
Food chemistry, 2015
The effect of the amount of immobilized Lactobacillus casei ATCC 393 on wheat grains on the gener... more The effect of the amount of immobilized Lactobacillus casei ATCC 393 on wheat grains on the generation of volatile compounds during the production of heat treated probiotic dry-fermented sausages was investigated. For comparison reasons, sausages containing free L. casei cells or no starter culture as well as a similar commercial product were also included in the study. Samples ripened for 8days and heat treated to 70-72°C for 8-10min were subjected to Solid Phase Microextraction (SPME) Gas Chromatography/Mass Spectrometry (GC/MS) analysis. The starter culture affected significantly the production of volatile compounds. The highest content of esters and alcohols was observed in the sample containing 30g of immobilized cells/kg of stuffing mixture, while the highest concentration of organic acids was observed in the sausages with no starter culture. In contrast, the commercial product contained the lowest concentration of volatiles. Principal component analysis of the semi-quantitati...
Meat science, 2015
The effect of immobilized Lactobacillus casei ATCC 393 on wheat grains on the generation of volat... more The effect of immobilized Lactobacillus casei ATCC 393 on wheat grains on the generation of volatile compounds in probiotic dry-fermented sausages during ripening was investigated. For comparison reasons, sausages containing free L. casei cells or no starter culture were also included in the study. Samples were collected after 1, 28 and 45days of ripening and subjected to SPME GC/MS analysis. Both the probiotic culture and the ripening process affected significantly the concentration of all volatile compounds. The significantly highest content of total volatiles, esters, alcohols and miscellaneous compounds was observed in sausages containing the highest amount of immobilized culture (300g/kg of stuffing mixture) ripened for 45days. Principal component analysis of the semi-quantitative data revealed that primarily the concentration of the immobilized probiotic culture affected the volatile composition.
Enzyme and microbial technology, 2014
Advantages in maltose fermentation at extremely low temperatures (5-10°C) using an alcohol resist... more Advantages in maltose fermentation at extremely low temperatures (5-10°C) using an alcohol resistant and cryotolerant yeast strain (Saccharomyces cerevisiae AXAZ-1) immobilized on porous cellulosic material (or tubular cellulose, TC), produced by delignification of wood sawdust, are reported. Pure maltose and glucose media (80, 100 and 140 g/l) were examined as model substrates to evaluate the potential effect of TC on the rate of fermentation of maltose containing substrates. The use of TC sharply accelerated the rate of maltose fermentation compared to free cells (FC) in suspension. Fermentation at 5°C by immobilized cells was complete, while FC were unable to ferment maltose at this temperature, in contrast to glucose, which was completely fermented. From the results of maltose and glucose fermentations at 5 and 10°C, it was concluded that the effect of TC was higher at lower fermentation temperature and that its promotional effect on fermentation rate had to be at the step of ma...
Bioresource Technology, 2015
The use of kissiris as promoter (culture immobilization carrier) in anaerobic acidogenesis of suc... more The use of kissiris as promoter (culture immobilization carrier) in anaerobic acidogenesis of sucrose, raffinose and vinasse is reported. Initially, the effect of pH (4-8) and fermentation temperature (18-52°C) on the accumulation of low molecular weight organic acids (OAs) during sucrose acidogenesis, was evaluated. The promoting effect of kissiris was confirmed compared to free cells, resulting in 80% increased OAs production. The optimum conditions (pH 8; 37°C) were used during acidogenesis of sucrose/raffinose mixtures. A continuous system was also operated for more than 2months. When sucrose and sucrose/raffinose mixtures were used, lactic acid type fermentation prevailed, while when vinasse was used, butyric acid type fermentation occurred. Total OAs concentrations were more than 14g/L and ethanol concentrations were 0.5-1mL/L. Culture adaptation in vinasse was necessary to avoid poor results. The proposed process is promising for new generation ester-based biofuel production from industrial wastes.
Journal of Food Science and Technology, 2014
Resin from Pistacia terebinthus tree was used for the immobilization of L. casei ATCC 393 cells. ... more Resin from Pistacia terebinthus tree was used for the immobilization of L. casei ATCC 393 cells. The encapsulated L. casei cells biocatalysts were added as adjuncts during yogurt production at 45°C and probiotic viability was assessed during storage at 4°C. For comparison reasons yogurt with free L. casei cells were prepared. The effect of encapsulated bacteria as adjuncts in yogurt on pH, lactic acid, lactose and other physicochemical parameters were studied for 60 storage days at 4°C. Samples were also tested for the microbiological and organoleptic characteristics during storage at 4°C. Encapsulation matrix seems to sustain the viability of embedded L. casei cells at levels more than 7 logcfug −1 after 60 days of storage at 4°C. Furthermore, the absence of p a t h o g e n s s u c h a s S a l m o n e l l a , S t a p h y l o c o c c i , Enterobacteriaceae and coliforms in the produced yogurts is noteworthy where spoilage microorganisms such as yeasts and molds seem to affect yogurt quality only in absence of Pistacia terebinthus resin. The effect of the resin on production of aroma-related compounds responsible for yogurt flavor was also studied using the solid phase microextraction gas chromatography/mass spectrometry technique. Alpha and beta-pinene were the major aroma compounds detected in produced yogurts (over 60 % of total aromatic compounds detected). Yogurts with immobilized cells on P.terebintus resin had a fine aroma and taste characteristic of the resin.
Process Biochemistry, 2003
Glycerol formation is reported in alcoholic fermentation with an alcohol resistant and psychrophy... more Glycerol formation is reported in alcoholic fermentation with an alcohol resistant and psychrophylic Saccharomyces cerevisiae strain immobilized on delignified cellulosic material (DCM) and gluten pellets (GP). The immobilized biocatalysts were used for successive fermentation batches of synthetic media (glucose, fructose and sucrose) and grape must. Generally, immobilization affects glycerol production positively. Glycerol concentration in the range 11.9 Á/14.9 g/l in wines was produced by immobilized cells and 10.2 Á/12.8 g/l was produced by free cells at fermentation temperatures 5 Á/30 8C. Glycerol concentration was affected by fermentation temperature and decreased as the temperature decreased for every fermenting medium. Glycerol concentration was higher in fermentations of grape must with immobilized or free cells than in those of synthetic media. The increased glycerol concentrations produced by immobilized yeast cells on DCM and GP support their use in wine making given that glycerol affects wine flavour and gives an impression of fullness and softness.
Journal of the Science of Food and Agriculture, 2005
... Correspondence: Athanasios A Koutinas, Food ... 15 Argiriou T, Kanellaki M, Voliotis S and Ko... more ... Correspondence: Athanasios A Koutinas, Food ... 15 Argiriou T, Kanellaki M, Voliotis S and Koutinas AA, Kissiris-supported yeast cells: high biocatalytic stability and productivity improvement by successive preservations at 0 °C. J Agric Food Chem 44: 40284031 (1996). ...
Journal of Food Engineering, 2009
A freeze-dried immobilized biocatalyst produced by immobilization of Saccharomyces cerevisiae AXA... more A freeze-dried immobilized biocatalyst produced by immobilization of Saccharomyces cerevisiae AXAZ-1 yeast cells on gluten pellets and subsequent freeze-drying was used in a multistage fixed-bed tower (MFBT) bioreactor for batch and continuous wine-making. The MFBT bioreactor resulted in higher alcohol productivity compared to fermentations carried out in a packed bed (PB) bioreactor and showed an important operational stability and no decrease in activity, even at low fermentation temperature (5°C) and after storage for 6 months at 4°C. The production of amyl alcohols proved to be temperature dependent and was significantly reduced at low temperatures. Re-activation of the freeze-dried immobilized cells after storage for 6 months resulted in further decreased content of amyl alcohols. The SPME GC/MS analysis of volatile compounds revealed no significant differences in the wines produced by MFBT and PB bioreactors, while the preliminary sensory evaluation ascertained the overall improved quality of the produced wines. Potential industrial application of MFBT bioreactor is also assessed and discussed.
Journal of Agricultural and Food Chemistry, 2005
In this work Lactobacillus casei ATCC 393 cells immobilized on delignified cellulosic material (D... more In this work Lactobacillus casei ATCC 393 cells immobilized on delignified cellulosic material (DCM) were used for malolactic fermentation (MLF) of wine. Wine was produced using yeast cells immobilized on DCM at 20 degrees C, and after alcoholic fermentation, MLF at 27 degrees C followed using immobilized L. casei ATCC 393 cells. A total of 11 repeated alcoholic and subsequent MLF batches were performed within a period of 1 month. As the repeated MLF batches proceeded, the MLF activity of the immobilized biocatalyst was reduced. Malic acid degradation was reduced from 80 to 2%, pH was reduced by 0.5-0.1 unit, acetic acid concentrations were slightly reduced or remained stable (0.002 g/L), the higher alcohols 1-propanol, isobutyl alcohol, and amyl alcohol were decreased by 84, 23, and 11%, respectively, and ethyl acetate concentration was increased by approximately 56%. Wine samples were analyzed by GC-MS before and after MLF, revealing some qualitative differences.
Journal of Agricultural and Food Chemistry, 2003
A biocatalyst was prepared by immobilization of Saccharomyces cerevisiae cells on grape skins. Re... more A biocatalyst was prepared by immobilization of Saccharomyces cerevisiae cells on grape skins. Repeated batch fermentations were conducted using this biocatalyst as well as free cells, at 25, 20, 15, and 10 degrees C. Solid phase microextraction (SPME) was used in monitoring the evolution of volatile byproducts. The effect of immobilization and temperature on evolution patterns of volatiles was obvious. The major part of esters was formed after consumption of 40-50% of the sugars. Similar processes were observed for amyl alcohols and 2-phenylethanol, whereas 1-propanol and 2-methyl-1-propanol were formed during the whole alcoholic fermentation period at an almost constant formation rate. Acetaldehyde and acetoin were synthesized in the early stages of fermentation. Afterward, their amount decreased. In most cases, immobilized cells exhibited higher formation rates of volatiles than free cells. The final concentration of esters was higher in wines produced by immobilized biocatalyst. Their amount increased with temperature decrease. The opposite was observed for higher alcohols.
Food Chemistry, 2007
A biocatalyst, prepared by immobilization of the psychrotolerant yeast strain Saccharomyces cerev... more A biocatalyst, prepared by immobilization of the psychrotolerant yeast strain Saccharomyces cerevisiae AXAZ-1 on delignified brewer’s spent grains, was used for brewing at very low temperatures, resulting in beers with fine clarity, excellent quality and mature character after the end of primary fermentation. Fermentation times were low (only 20 days at 0°C), while ethanol and beer productivities were high, showing
Enzyme and Microbial Technology, 2007
Industrial scale-up of whey fermentation, promoted by raisin extracts, using free kefir-yeast cel... more Industrial scale-up of whey fermentation, promoted by raisin extracts, using free kefir-yeast cells is reported. The fermented whey would be exploited as raw material to produce kefir-like whey-based drinks, potable and fuel alcohol, as well as kefir-yeast biomass for use as baker's yeast. The scale-up process involved the development of a technology transfer scheme from lab-scale experiments to a successive series of increased capacity bioreactors (100, 3000 and 11,000 L). The development of this technology was supported by the six-fold promotion of whey fermentation by the addition of 1% black raisin extracts (optimum concentration found in this investigation), as well as by the formation of kefir-yeast in the form of easily precipitated granular biomass that led to the avoidance of centrifugal separators, which are equipment of high cost. A cost analysis showed a big reduction of the production cost of the aforementioned products in comparison with the market prices, attributed to the negligible cost of raw materials (whey) and the granular biomass formation.
Bioresource Technology, 2014
h i g h l i g h t s Contribution on a new generation biofuel based on VFAs production by acidogen... more h i g h l i g h t s Contribution on a new generation biofuel based on VFAs production by acidogenic fermentation. Acidogenic fermentation of glucose advantaged by immobilised cells on c-alumina. Higher VFA yields obtained at substrate concentrations lower than 50 g glucose/L using immobilised cells. Butyric-type fermentation enhanced by continuous operation at high pH (9) using immobilised cells.
Bioresource Technology, 2014
h i g h l i g h t s Porous cellulosic materials and composites for cell immobilisation. Improveme... more h i g h l i g h t s Porous cellulosic materials and composites for cell immobilisation. Improvements in lactic acid fermentation by immobilised L. bulgaricus cells. Possible use of the three-layer composites for multispecies co-immobilisation.