76 research outputs found
1,3-Propanediol production from crude glycerol by Clostridium butyricum DSP1 in repeated batch
AbstractBackgroundThe production of biofuels from renewable energy sources is one of the most important issues in industrial biotechnology today. The process is known to generate various by-products, for example crude glycerol, which is obtained in the making of biodiesel from rapeseed oil. Crude glycerol may be utilized in many ways, including microbial conversion to 1,3-propanediol (1,3-PD), a raw material for the synthesis of polyesters and polyurethanes.ResultsThe paper presents results of a study on the synthesis of 1,3-propanediol from crude glycerol by a repeated batch method with the use of Clostridium butyricum DSP1. Three cycles of fermentation medium replacement were carried out. The final concentration of 1,3-PD was 62g/L and the maximum productivity, obtained during the second cycle, reached 1.68g/L/h. Additionally, experiments conducted in parallel to the above involved using the entire quantity of the culture broth removed from the bioreactor to inoculate successive portions of fermentation media containing crude glycerol at concentrations of 80g/L and 100g/L. Under those conditions, the maximum 1,3-PD concentrations were 43.2g/L and 54.2g/L.ConclusionsThe experiments proved that by using a portion of metabolically active biomass as inoculum for another fermentation formula it is possible to eliminate the stage of inoculum growth and thereby reduce the length of the whole operation. Additionally, that strategy avoids the phase of microbial adaptation to a different source of carbon such as crude glycerol, which is more difficult to utilize, thus improving the kinetic parameters of 1,3-PD production
1,3-Propanediol production fromcrude glycerol by Clostridium butyricum DSP1 in repeated batch
Background: The production of biofuels from renewable energy sources is
one of the most important issues in industrial biotechnology today. The
process is known to generate various by-products, for example crude
glycerol, which is obtained in the making of biodiesel from rapeseed
oil. Crude glycerol may be utilized in many ways, including microbial
conversion to 1,3-propanediol (1,3-PD), a raw material for the
synthesis of polyesters and polyurethanes. Results: The paper presents
results of a study on the synthesis of 1,3-propanediol from crude
glycerol by a repeated batch method with the use of Clostridium
butyricum DSP1. Three cycles of fermentation medium replacement were
carried out. The final concentration of 1,3-PD was 62 g/L and the
maximum productivity, obtained during the second cycle, reached 1.68
g/L/h. Additionally, experiments conducted in parallel to the above
involved using the entire quantity of the culture broth removed from
the bioreactor to inoculate successive portions of fermentation media
containing crude glycerol at concentrations of 80 g/L and 100 g/L.
Under those conditions, the maximum 1,3-PD concentrations were 43.2 g/L
and 54.2 g/L. Conclusions: The experiments proved that by using a
portion of metabolically active biomass as inoculum for another
fermentation formula it is possible to eliminate the stage of inoculum
growth and thereby reduce the length of the whole operation.
Additionally, that strategy avoids the phase of microbial adaptation to
a different source of carbon such as crude glycerol, which is more
difficult to utilize, thus improving the kinetic parameters of 1,3-PD
production
An increasing of the efficiency of microbiological synthesis of 1,3-propanediol from crude glycerol by the concentration of biomass
Background: 1,3-Propanodiol (1,3-PD), is used in the production of
polytrimethylene terephthalate (PTT), an aromatic polyester that
exhibits high elastic recoveries. It is also employed as a
supplementwith lowsolidification properties, a solvent and a lubricant
in the formof propylene glycol. 1,3-PD is effectively synthesized by a
microbiological way from crude glycerol. The main problem of this
technology is using a high concentration of glycerol, which is a
limiting factor for bacteria cells growth (especially in batch
fermentation). Results: In this work, the influence of different
glycerol concentration in batch fermentation on Clostridium butyricum
DSP1 metabolism was investigated. The biomass was concentrated for two
times with the use of membrane module (in case of increasing kinetic
parameters). Increased optical density of bacteria cells six times
increased the productivity of 1,3-PD in cultivation with 20 g/L of
glycerol at the beginning of the process, and more than two times in
cultivation with 60\u201380 g/L. Also the possibility of complete
attenuation of 140 g/L of crude glycerol in the batch fermentation was
investigated. During the cultivation, changes of protein profiles were
analyzed. The most significant changes were observed in the cultivation
in the medium supplemented with 80 g/L of glycerol. They related mainly
to the DNA protein reconstructive systems, protective proteins (HSP),
and also the enzymatic catalysts connected with glycerol metabolic
pathway. Conclusions: The application of filtration module in batch
fermentation of crude glycerol by C. butyricum DSP1 significantly
increased the productivity of the process
The Influence of Excipients on the Physicochemical and Biological Properties of a Bactericidal, Labile Ester Prodrug in a Salt Form – A Case Study of Cefetamet Pivoxil Hydrochloride
The article presents an innovative approach to a bactericidal drug design based on a cephem prodrug analogue – cefetamet pivoxil hydrochloride. The emergence of cefetamet pivoxil hydrochloride excipient systems (mannitol, hydroxypropyl methyl cellulose, pregelatinised starch, lactose monohydrate, magnesium stearate, polyvinylpyrrolidone) caused changes in the physicochemical properties of cefetamet pivoxil hydrochloride. They are significant for planning the development of an innovative pharmaceutical formulation. The biological activity profile of the prodrug was also modified. FTIR spectra were used to study interactions between cefetamet pivoxil hydrochloride and the excipients. The theoretical approach to the analysis of experimental spectra enabled precise indication of cefetamet pivoxil hydrochloride domains responsible for interaction with the excipients. The interactions between cefetamet pivoxil hydrochloride and the excipients resulted in some important physicochemical modifications: acceptor fluid-dependent changes in solubility and the dissolving rate as well as a decrease in the chemical stability of cefetamet pivoxil hydrochloride in the solid state, especially during thermolysis. The interactions between cefetamet pivoxil hydrochloride and the excipients also had biologically essential effects. There were changes in its permeability through artificial biological membranes simulating the gastrointestinal tract, which depended on the pH value of the acceptor solution. Cefetamet pivoxil hydrochloride combined with the excipient systems exhibited greater bactericidal potential against Staphylococcus aureus. Its bactericidal potential against Enterococcus faecalis, Pseudomonas aeruginosa and Proteus mirabilis doubled. The new approach provides an opportunity to develop treatment of resistant bacterial infections. It will enable synergy between the excipient and the pharmacological potential of an active pharmaceutical substance with modified physicochemical properties induced by the drug carrier
Evaluation of the ability to metabolize 1,2-propanediol by heterofermentative bacteria of the genus Lactobacillus
Background: New directions of research on lactic acid bacteria include
investigation of metabolic pathways for the synthesis and/or metabolism
of 1,2-propanediol, commonly used in the food and chemical industry,
medicine, pharmacy and cosmetology as well as agriculture. The
objective of this study was to compare the capacity of strains
representing three diverse heterofermentative species belonging to the
genus Lactobacillus to synthesize and/or transform 1,2-PD as well as to
suggest new directions of research aimed at commercial use of this
metabolite. Results: The novel strain of Lactobacillus buchneri A KKP
2047p, characterized as exhibiting an unusual trait for that species in
the form of capacity to metabolize 1,2-PD, grew poorly in a medium
containing 1,2-PD as a sole carbon source. The supplementation with
glucose facilitated rapid growth of bacteria and use of 1,2-PD for the
synthesis of propionic acid. A similar observation was noted for
Lactobacillus reuteri . On the other hand, Lactobacillus diolivorans
effectively metabolized 1,2-PD which was the sole carbon source in the
medium, and the addition of glucose inhibited the synthesis of
propionic acid. The experiments also investigated the effect of
cobalamin as a diol dehydratase coenzyme involved in the propionic acid
synthesis from 1,2-PD whose addition promoted the yield of the reaction
in the case of all tested strains. Conclusions: All tested isolates
showed the ability to effectively metabolize 1,2-PD (in the presence of
cobalamin) and its conversion to propionic acid, which reveals that
investigated bacteria meet the essential requirements of microorganisms
with a potential application
Assessment of the molecular cytogenetic, morphometric and biochemical parameters of Deschampsia antarctica from its southern range limit in maritime Antarctic
Different chromosomal forms of Deschampsia antarctica Desv. (Poaceae),
including diploids (2n=26), hypotriploid (2n=36–38) and a genotype with an occasional
occurrence of B chromosome (2n=26+0-1B) that originated from southern marginal
populations (Argentine Islands region, maritime Antarctic) were studied using molecular
cytogenetic, morphometric and biochemical methods. FISH analysis revealed variations
in the number of rDNA sites between the diploid and hypotriploid plants. The genome
size varied among plants with a different chromosome number and was on average
10.88 pg/2C for diploids and 16.46 pg/2C for hypotriploid. The mean values of leaf
length of plants grown in vitro varied within a range of 5.23–9.56 cm. The total phenolic
content ranged from 51.10 to 105.40 mg/g, and the total flavonoid content ranged
from 1.22 to 4.67 mg/g. The amount of phenolic compounds did not differ significantly
between the genotypes, while a variation in the flavonoid content was observed for L59
and DAR12. The diploids did not differ significantly among each other in terms of the
number of rDNA loci, but differed slightly in their genome size. The individuals of DAR12
carrying B chromosome were similar to other diploids in terms of their genome size, but statistically differed in leaf length. The hypotriploid had both a greater number of rDNA
sites and a larger genome size. No statistical correlations were observed between the
genome size and leaf length or genome size and accumulation of phenolic and flavonoid
compounds. The results of this study suggest that D. antarctica plants from the southern
edge of the range are characterised by the heterogeneity of the studied parameters
The effect of high concentrations of glycerol on the growth, metabolism and adaptation capacity of Clostridium butyricum DSP1
Background: The production of biofuels from renewable energy sources is one of the most important issues in biotechnology today. The process is known to generate various by-products, for example glycerol that is obtained in the making of biodiesel from rapeseed oil. Crude glycerol may be utilized in many ways, including microbial conversion to 1,3-propanediol. The main drawback of that technology is the use of high concentrations of glycerol, which inhibits the growth of bacterial cells.
Results: This study investigated the impact of crude glycerol on Clostridium butyricum DSP1 and its ability to adapt to an environment of high osmotic pressure. It was found that a crude glycerol concentration of up to 70 g/L did not have an inhibitory effect on C. butyricum DSP1. Adaptation procedures involving the passage of metabolically active biomass from a fermentation medium with a lower concentration of crude glycerol to one with a greater substrate concentration allowed breaking the barrier of high osmotic pressure (150 g/L crude glycerol) and receiving a 1,3-PD concentration of 74 g/L in a batch culture operation. The work looked into intracellular modifications shown by proteomic profiling in order to explain the mechanisms underlying the response and adaptation of bacterial cells exposed to unfavorable environmental conditions.
Conclusions: This study of the effect of glycerol on the growth and metabolism of C. butyricum DSP1 demonstrated that the maximum substrate concentrations that do not inhibit the metabolic activity of bacterial cells are 90 g/L and 70 g/L for pure and crude glycerol, respectively
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