Proceedings,Venice 2012, Fourth International Symposium on Energy from Biomass and Waste,ISBN:978-88-6265-006-9, Nov 12, 2012
"Volatile fatty acids (VFA) including acetic, butyric, formic and propionic are extensively utili... more "Volatile fatty acids (VFA) including acetic, butyric, formic and propionic are extensively utilized in contemporary industry. Their commercial value is of high significance while their often derive from petroleum which is non-abundance source. Other methods for the production and recovery from these substances have been proposed and investigated. Waste effluent streams are potential candidates for VFA recovery, especially if for their processing filtration technology will be used. Membrane filtration is an effective and efficient choice as it is a low cost, low energy, easy integrated method tested for the separation and concentration.
"
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In order to achieve that, the optimised medium was then filtrated via ultrafiltration membrane modules of 30 and 4 kDa MWCO , in an effort to simplify the medium and facilitate the extraction of the produced substance. The medium’s efficiency in supporting the growth and the bacteriocin production of the bacilli was tested and comparative studies between filtrated and unfiltrated media were done.The filtered medium, containing low molecular weight nutrient sources, was proven to to successfully support growth and bacteriocin production.
Keywords: LAB, Bacteriocins, Target strain, Ultrafiltration, Growth rate, DT.
Three Lactobacilli strains, Lactobacillus casei NCIMB 11970 Lactobacillus plantarum NCIMB 8014, Lactobacillus lactis NCIMB 8586 have been used for the production of bacteriocins. Though their production phase, their biochemical nature , their mode of activity even their genetic structure have been widely investigated, there are hardly any studies investigating their potency and activity in depth of time, in other words their self life under several physicochemical conditions that may occur during their production in large scale.
As such the effect of several factors influencing the activity and the potency of bacteriocins when produced in large scale were examined as due to bacteriocins peptide nature be degradation or denaturation might occur, under extreme physicochemical conditions. During scale up process, differences between the output data may occur, such as concerning biomass, metabolic by products and limiting substrate concentrations. These may affect negatively, the activity and the potency of the bacteriocins. For investigating these effects and minimising them, numerous studies were conducted, which were related to the exact phase of the production of these substances, the effect of dilution and temperature changes. These studies could be used in order to minimise the scaling up effect when decided to produce these peptides in large scale.
. Materials and Methods
Nisin solutions of 1000 IU/ml, crude extracts of the fermented media by Lactobacilli and treated supernatants containing bacteriocins were serially diluted. These were tested for potency against the indicator strain L.delbruckii subsp.lactis NCIMB 8117 and their activity was calculated in international units per millilitre (IU/ml) according to the dose response model fabricated. Mechanical stress was applied to the produced bacteriocins and nisin through microfiltration (0.2μm MWCO) and ultrafiltration (30kDa MWCO). Heat tolerance was also tested in a range of temperature of 40, 60, 80 and 100°C for 15, 30, 45, and 60 minutes time interval in each temperature. The stability of the bacteriocins in low temperatures was also tested. The solutions were kept in 4°C for 12, 48, 60, 72, 84 and 96h.
Results
The bacteriostatic effect of the produced bacteriocins and nisin treated with several methods, was strong up to the first 48h, though the target strain started getting in the death phase. The most sensitive bacteriocin is proven to be the one deriving from L.lactis, as it is partially loses its potency when heated in 80°C. These substances were proven to be sensitive when treated with in very high temperatures but are relatively stable. They maintain though their stability and potency even up to 72 h of storage.
.Discussion and Conclusion
When concentrated ,the bacteriocins were causing death of the target strain within 48h. They also retained their potency against the target strain for up to 60 h of storage. Treatment though with heat and microfiltration caused partial loss of potency, though the bacteriocin deriving from L.plantarum was proven to be most active. On the whole these substances were stable and there is potential to scale these processes for production knowing that if handled correctly they will not be significant losses."""
These bacteria have numerous features, which are based on their main ability to ferment complex carbohydrates such as the production of acids, enzymes and natural antimicrobial substances called bacteriocins. Currently, they are principally used as natural acidifiers for the inoculation of bulk quantities of milk and vegetables in order to produce a variety of fermented products. some of the most important uses of Lactobacilli in the industry will be reviewed. The production of lactic acid and lantibiotics through the usage of modern fermentation technology, shall be highlighted
Keywords:Lactobacilly, LAB, fermentation science, biochemical engineering, industry, bacteriocins, lactic acid""
Keywords: microfiltration, anaerobic digestion, sludge, nutrient media, bacterial growth, biofuels, acid, wastewater treatment
The growth efficiency on the medium was tested on a 2L STR reactor operated batch wise with continuous pH control. The optimum pH conditions for the growth of the bacilli were determined as well as parameters such as cellular yield coefficient, substrate and starter inoculum concentration and lactic acid rate and production. The metabolism of the Lactobacilli was determined as homofermentative, mainly producing lactic acid.
The efficiency of the optimized medium was evaluated in terms of growth rate and doubling time through the spectrophotometric measurement of cellular biomass.
Keywords: LAB, STR, Growth rate, Doubling time, lactic acid, nutrient medium
Keywords: waste process, nutrients, particle size, dry matter, ammonia, phosphate, environment, conductivity, salinity, sludge""
Keywords: Lactic acid bacteria, Lactobacilli, Bacteriocins, Nisin, Plantaricins, Lantibiotics
The growth efficiency on the medium was tested on a 2L STR reactor operated batch wise with continuous pH control. The optimum pH conditions for the growth of the bacilli were determined as well as parameters such as cellular yield coefficient, substrate and starter inoculum concentration and lactic acid rate and production. The metabolism of the Lactobacilli was determined as homofermentative, mainly producing lactic acid.
The efficiency of the optimized medium was evaluated in terms of growth rate and doubling time through the spectrophotometric measurement of cellular biomass.
Keywords: LAB, STR, Growth rate, Doubling time, lactic acid, nutrient medium.
Index Terms-Doubling time, Growth rate, Lactic acid, Nisin
Keywords: LAB, STR, Growth rate, Doubling time, lactic acid, nutrient medium.
Keywords: LAB, fermentation technology, food industry, β-galactosidase, lactic acid.
"
lactobacilli and lactococcoi bacteriocins include chemical precipitation, separation employing solvents
and chromatographic techniques. These methods are arduous, costly, with limited scalability, offering
low bacteriocin yields (<20%). To address these challenges, the alternatives of ultrafiltration and
nanofiltration, as separation methods were tested. Three promising bacteriocin producing strains,
Lactobacillus casei NCIMB 11970, Lactobacillus plantarum NCIMB 8014 and Lactococcus lactis NCIMB
8586 were selected to investigate the applicability and feasibility of the method.
To facilitate separation, the microorganisms were grown on specially developed low molecular weight
medium (LMWM) mainly containing nutritive sources up to 4 kDa molecular weight. Bacterial cells
were removed by centrifugation. The clarified broths were filtered using 4 and 1 kDa MWCO.
Bacteriocin activity was determined by an antimicrobial activity test using nisin, which has an
inhibitory effect on the growth of susceptible microorganisms. Recovery yields using filtration were
found to range between 53 to 68%, a high recovery performance.
The bacteriocin activity of crude extracts of all the three lactobacilli were between 95-105 IU ml-1.
When the substances were separated using ultrafiltration membrane (4kDa MWCO) their activity was
enhanced to 145-150 IU ml-1, achieving a total potency yield of 44% to 53%. Further enhancement of
yields up to 36% was attained employing nanofiltration (1 kDa MWCO) membranes with an activity
increased up to 200 IU ml-1.
Bacteriocin isolation from crude extracts using filtration was found to be effective, offering high
recovery yields, optimizing their activity as well as presenting a realistic option towards the
formulation of these as commercially available antibacterial agents.
awareness of the environmental impact the carbon based economy has created, research has been focused in
developing alternative methods of their production. These include fermentation, anaerobic digestion and recovery
from discharged chemical and industrial plants effluents.
During these processes, the hydrolysis of target solid wastes followed by the microbial conversion of them to
biodegradable organic, content results in the production of intermediate VFA, commonly acetate and butyrate.
These, are detected at varying concentrations in the effluent streams and mixed liquors of the reactor systems. Their
concentration is depending on hydraulic, retention and organic loading rates. Several studies have shown possible environmental and commercial benefits using various techniques for their separation and recovery. Among these, extensively applied has been reactive extraction. Currently, membrane
filtration is most prominent as a source separation process in comparison to integral wastewater treatment.
VFA reclamation benefits include the formulation of a valorisized waste effluent that can be further processed for the recovery of valuable nutrients, the relief of municipal treatment plants and the recycle and re-use of favorable nutrients and chemicals."
Keywords: sludge; ceramic filter; cake resistance; flux; cross flow filtration"
The possibility of producing these substances in mass quantities will be investigated through several techniques. Three carefully selected Lactobacilli, L.plantarum NCIMB 8014, L.casei NCIMB 11970 and L.lactis NCIMB 8586 were grown into simple batch cultures without pH control, where their physicochemical needs were determined. Through the determination of the optimum nutritional conditions for their propagation an optimised growth medium occurred. A simple, liquid turbidometric method was developed to test the bacteriocin productivity of these strains. The antimicrobial activity and potency of the bacteriocins produced, were tested against the target strain L.delbruckii subsp.lactis NCIMB 8117.
The optimised medium was then filtrated via membrane modules of 4 and 30 kDa , in an effort to simplify the medium and facilitate the extraction of the produced substance. The medium’s efficiency in supporting the growth and the bacteriocin production of the bacilli was tested and comparative studies between filtrated and unfiltrated media were done.
Keywords: LAB, Bacteriocins, Target strain, Ultrafiltration, Growth rate, Doubling time""
In order to achieve that, the optimised medium was then filtrated via ultrafiltration membrane modules of 30 and 4 kDa MWCO , in an effort to simplify the medium and facilitate the extraction of the produced substance. The medium’s efficiency in supporting the growth and the bacteriocin production of the bacilli was tested and comparative studies between filtrated and unfiltrated media were done.The filtered medium, containing low molecular weight nutrient sources, was proven to to successfully support growth and bacteriocin production.
Keywords: LAB, Bacteriocins, Target strain, Ultrafiltration, Growth rate, DT.
Three Lactobacilli strains, Lactobacillus casei NCIMB 11970 Lactobacillus plantarum NCIMB 8014, Lactobacillus lactis NCIMB 8586 have been used for the production of bacteriocins. Though their production phase, their biochemical nature , their mode of activity even their genetic structure have been widely investigated, there are hardly any studies investigating their potency and activity in depth of time, in other words their self life under several physicochemical conditions that may occur during their production in large scale.
As such the effect of several factors influencing the activity and the potency of bacteriocins when produced in large scale were examined as due to bacteriocins peptide nature be degradation or denaturation might occur, under extreme physicochemical conditions. During scale up process, differences between the output data may occur, such as concerning biomass, metabolic by products and limiting substrate concentrations. These may affect negatively, the activity and the potency of the bacteriocins. For investigating these effects and minimising them, numerous studies were conducted, which were related to the exact phase of the production of these substances, the effect of dilution and temperature changes. These studies could be used in order to minimise the scaling up effect when decided to produce these peptides in large scale.
. Materials and Methods
Nisin solutions of 1000 IU/ml, crude extracts of the fermented media by Lactobacilli and treated supernatants containing bacteriocins were serially diluted. These were tested for potency against the indicator strain L.delbruckii subsp.lactis NCIMB 8117 and their activity was calculated in international units per millilitre (IU/ml) according to the dose response model fabricated. Mechanical stress was applied to the produced bacteriocins and nisin through microfiltration (0.2μm MWCO) and ultrafiltration (30kDa MWCO). Heat tolerance was also tested in a range of temperature of 40, 60, 80 and 100°C for 15, 30, 45, and 60 minutes time interval in each temperature. The stability of the bacteriocins in low temperatures was also tested. The solutions were kept in 4°C for 12, 48, 60, 72, 84 and 96h.
Results
The bacteriostatic effect of the produced bacteriocins and nisin treated with several methods, was strong up to the first 48h, though the target strain started getting in the death phase. The most sensitive bacteriocin is proven to be the one deriving from L.lactis, as it is partially loses its potency when heated in 80°C. These substances were proven to be sensitive when treated with in very high temperatures but are relatively stable. They maintain though their stability and potency even up to 72 h of storage.
.Discussion and Conclusion
When concentrated ,the bacteriocins were causing death of the target strain within 48h. They also retained their potency against the target strain for up to 60 h of storage. Treatment though with heat and microfiltration caused partial loss of potency, though the bacteriocin deriving from L.plantarum was proven to be most active. On the whole these substances were stable and there is potential to scale these processes for production knowing that if handled correctly they will not be significant losses."""
These bacteria have numerous features, which are based on their main ability to ferment complex carbohydrates such as the production of acids, enzymes and natural antimicrobial substances called bacteriocins. Currently, they are principally used as natural acidifiers for the inoculation of bulk quantities of milk and vegetables in order to produce a variety of fermented products. some of the most important uses of Lactobacilli in the industry will be reviewed. The production of lactic acid and lantibiotics through the usage of modern fermentation technology, shall be highlighted
Keywords:Lactobacilly, LAB, fermentation science, biochemical engineering, industry, bacteriocins, lactic acid""
Keywords: microfiltration, anaerobic digestion, sludge, nutrient media, bacterial growth, biofuels, acid, wastewater treatment
The growth efficiency on the medium was tested on a 2L STR reactor operated batch wise with continuous pH control. The optimum pH conditions for the growth of the bacilli were determined as well as parameters such as cellular yield coefficient, substrate and starter inoculum concentration and lactic acid rate and production. The metabolism of the Lactobacilli was determined as homofermentative, mainly producing lactic acid.
The efficiency of the optimized medium was evaluated in terms of growth rate and doubling time through the spectrophotometric measurement of cellular biomass.
Keywords: LAB, STR, Growth rate, Doubling time, lactic acid, nutrient medium
Keywords: waste process, nutrients, particle size, dry matter, ammonia, phosphate, environment, conductivity, salinity, sludge""
Keywords: Lactic acid bacteria, Lactobacilli, Bacteriocins, Nisin, Plantaricins, Lantibiotics
The growth efficiency on the medium was tested on a 2L STR reactor operated batch wise with continuous pH control. The optimum pH conditions for the growth of the bacilli were determined as well as parameters such as cellular yield coefficient, substrate and starter inoculum concentration and lactic acid rate and production. The metabolism of the Lactobacilli was determined as homofermentative, mainly producing lactic acid.
The efficiency of the optimized medium was evaluated in terms of growth rate and doubling time through the spectrophotometric measurement of cellular biomass.
Keywords: LAB, STR, Growth rate, Doubling time, lactic acid, nutrient medium.
Index Terms-Doubling time, Growth rate, Lactic acid, Nisin
Keywords: LAB, STR, Growth rate, Doubling time, lactic acid, nutrient medium.
Keywords: LAB, fermentation technology, food industry, β-galactosidase, lactic acid.
"
lactobacilli and lactococcoi bacteriocins include chemical precipitation, separation employing solvents
and chromatographic techniques. These methods are arduous, costly, with limited scalability, offering
low bacteriocin yields (<20%). To address these challenges, the alternatives of ultrafiltration and
nanofiltration, as separation methods were tested. Three promising bacteriocin producing strains,
Lactobacillus casei NCIMB 11970, Lactobacillus plantarum NCIMB 8014 and Lactococcus lactis NCIMB
8586 were selected to investigate the applicability and feasibility of the method.
To facilitate separation, the microorganisms were grown on specially developed low molecular weight
medium (LMWM) mainly containing nutritive sources up to 4 kDa molecular weight. Bacterial cells
were removed by centrifugation. The clarified broths were filtered using 4 and 1 kDa MWCO.
Bacteriocin activity was determined by an antimicrobial activity test using nisin, which has an
inhibitory effect on the growth of susceptible microorganisms. Recovery yields using filtration were
found to range between 53 to 68%, a high recovery performance.
The bacteriocin activity of crude extracts of all the three lactobacilli were between 95-105 IU ml-1.
When the substances were separated using ultrafiltration membrane (4kDa MWCO) their activity was
enhanced to 145-150 IU ml-1, achieving a total potency yield of 44% to 53%. Further enhancement of
yields up to 36% was attained employing nanofiltration (1 kDa MWCO) membranes with an activity
increased up to 200 IU ml-1.
Bacteriocin isolation from crude extracts using filtration was found to be effective, offering high
recovery yields, optimizing their activity as well as presenting a realistic option towards the
formulation of these as commercially available antibacterial agents.
awareness of the environmental impact the carbon based economy has created, research has been focused in
developing alternative methods of their production. These include fermentation, anaerobic digestion and recovery
from discharged chemical and industrial plants effluents.
During these processes, the hydrolysis of target solid wastes followed by the microbial conversion of them to
biodegradable organic, content results in the production of intermediate VFA, commonly acetate and butyrate.
These, are detected at varying concentrations in the effluent streams and mixed liquors of the reactor systems. Their
concentration is depending on hydraulic, retention and organic loading rates. Several studies have shown possible environmental and commercial benefits using various techniques for their separation and recovery. Among these, extensively applied has been reactive extraction. Currently, membrane
filtration is most prominent as a source separation process in comparison to integral wastewater treatment.
VFA reclamation benefits include the formulation of a valorisized waste effluent that can be further processed for the recovery of valuable nutrients, the relief of municipal treatment plants and the recycle and re-use of favorable nutrients and chemicals."
Keywords: sludge; ceramic filter; cake resistance; flux; cross flow filtration"
The possibility of producing these substances in mass quantities will be investigated through several techniques. Three carefully selected Lactobacilli, L.plantarum NCIMB 8014, L.casei NCIMB 11970 and L.lactis NCIMB 8586 were grown into simple batch cultures without pH control, where their physicochemical needs were determined. Through the determination of the optimum nutritional conditions for their propagation an optimised growth medium occurred. A simple, liquid turbidometric method was developed to test the bacteriocin productivity of these strains. The antimicrobial activity and potency of the bacteriocins produced, were tested against the target strain L.delbruckii subsp.lactis NCIMB 8117.
The optimised medium was then filtrated via membrane modules of 4 and 30 kDa , in an effort to simplify the medium and facilitate the extraction of the produced substance. The medium’s efficiency in supporting the growth and the bacteriocin production of the bacilli was tested and comparative studies between filtrated and unfiltrated media were done.
Keywords: LAB, Bacteriocins, Target strain, Ultrafiltration, Growth rate, Doubling time""
LAB in the form of starter cultures are used in dairy wine and food processing industry. Their applications include enhancing the natural ripening of milk and plant origin products, such as butter, cheese, olives and cucumbers.
Numerous Lactobacillus strains are producing antimicrobial compounds called bacteriocins. Major group are the so called Lantibiotics. Lantibiotics are mainly active against bacteria of the same genus they are produced during growth of the bacilli, especially during exponential phase. These metabolic end products can be used as natural preservatives and antimicrobial agents against contamination and food spoilage occurring during or after the fermentation process, and their applications have been a matter of research lately. In this project novel methods for their production will be proposed.
The LMWM were made through serial filtration (filters varying in pore size 30kDa, 4 kDa and 1 kDa MWCO) of a modified optimum liquid medium for Lactobacilli growth. The developed media were tested for bacteriocin production and biomass growth, using three known bacteriocin producing Lactobacilli strains, Lactobacillus casei NCIMB 11970, Lactobacillus plantarum NCIMB 8014, Lactobacillus lactis NCIMB 8586. All were successfully grown (μmax 0.16 to 0.18 h-1 ) on the LMWM and produced a significant amount of bacteriocins in a range of 95 to 100 IU ml-1 in the crude extracts while when the substances were further with a 4kDa and 1kDa membrane their activity was enhanced to 175-190 IU ml-1, with filtration technology establishing an alternative to the current production methods.
"