Investigations Into Succinic Acid Fermentation

Succinic acid (SA) is an important chemical intermediate from which fine chemicals ( e.g. detergents), additives (for pharmaceuticals, food (taste), plant growth stimulants) as well as other important intermediates (maleic anhydride, succinimide, 2-pyrrolidinone, dimethyl succinate) can be manufactured. Since SA is involved in the central metabolism of cells (in the tricarboxylic acid (TCA) cycle), it is a key player in the biochemistry of life, which has the potential of biotechnological production. Since SA is formed in the ``middle'' of the TCA cycle it can be formed by both CO2 production and fixation. The significance of the latter is that the amount of the product can be controlled by the availability of CO2, since stoichiometrically one molecule of CO2 is fixed by one molecule of SA. In our studies of compositions of Actinobacillus succinogenes media, the role and effect of pH regulator compounds as well as the effect of an inert atmosphere were investigated in terms of the yield. Furthermore, in fermentation experiments, the application of higher sugar concentrations was also studied. On the basis of different fermentations, a neural network for modelling and describing how factors influence SA production was established

Corporate abilities

This brief paper aims to discuss (as a review) the notion of organisational/corporate abilities, a term that, albeit frequently used in the business world, often presents ambiguities in terms of its meaning. We tried to uncover an exact definition for it using different approaches, as well as models of organisational description and/or diagnostic value; however, none of these could provide us with a distinct answer. As the paper could not afford to undertake the introduction of every single approach that has so far been laid down in this subject, we cannot endeavour to formulate our own definition; our work only serves to illustrate that the concept has deeper meanings and thus cannot be used without interpretation. It can have different meanings, which sometimes inhibits the factual description of a given scenario, even though that is what terminologies are usually for. We have concluded that an accurate definition of the concept would be essential, as those specialising in organisational science could benefit from its standardised use.Organisational competence, organizational ability, managerial science, management tools, organiszational science, organisational diagnosis

Investigations into Enzymatic Bioconversion to Form Rebaudioside A from Stevioside

Stevia rebaudiana Bertoni is a perennial shrub from South America that produces steviol glycosides which are 200-300 times sweeter than sugar. Stevioside and rebaudioside A are the main sweetening components of its leaves. Steviol glycosides are diterpenoids whose biosynthetic pathways have four steps in common with gibberellic acid formation. The most important enzyme in the biosynthetic pathway expressed by the gene UGT76G1 is referred to as UDP-glycosyltransferase 76G1. It converts stevioside into rebaudioside A. The former has a bitter aftertaste and is a poorer sweetener but is most abundant. This enzyme can be produced in a next generation recombinant way by Escherichia coli and Saccharomyces cerevisiae. Trichoderma longibrachiatum produces the enzyme β-1,3-glucanase enzyme, which can perform a transglycosylation between stevioside to gain rebaudioside A. In our study, a full-factorial statistical experimental design that applies different glycosyl donors, temperatures, enzyme-to-substrate ratios and pH's as factors in order to achieve higher Reb A ratios in S. rebaudiana extracts after transglycosylation is reported. The presented statistical design was appropriate to indicate relevant and significant factors, providing a good basis for an upcoming experimental design of a real-world optimization

Bio-produced Acetic Acid: A Review

Acetic acid is an important platform chemical. It is mainly produced synthetically and only 10 percent of the world production is manufactured by bacterial fermentation for making vinegar. Several microorganisms can produce acetic acid and a part of them can incorporate CO2 during the production. In this review we summarized the microbial acetic acid pathways, and the used processes for vinegar production furthermore the optional acetic acid recovery operations to establish a complete possible biotechnological acetic acid production

Bio-produced Propionic Acid: A Review

Propionic acid is a platform chemical, antifungal agent and important chemical intermediate. Current industrial production of propionic acid is mainly through petrochemical processes because the conventional method of the propionic acid fermentation is uneconomical due to low product yield, productivity and product concentration caused by end-product inhibition. The coproduction of acetic and succinic acids in the propionic acid fermentation processes also makes downstream processing more complicated and costly. To the best of our knowledge there are several and recent reviews in the available literature on propionic acid fermentation processes and strain improvement techniques, but only a few on product recovery and purification, i.e. downstreaming. However, to realize a biorefinery, where propionic acid is a key intermediate, complex discussion of up-, and downstreaming is required. Therefore in this review a short overview of the whole bio-based propionic acid production process is presented including recent results of both upstream and downstream area. Thus the biosynthetic pathways, the significant results of native and recombinant producer strains as well as product recovery are discussed

Applicability of Neural Networks for the Fermentation of Propionic Acid by Propionibacterium acidipropionici

According to our best knowledge, this is the first report applying Artificial neural networks (ANN) for simulation of batch propionic acid (PA) fermentation. Therefore, the main focus of this research was to investigate the applicability of ANN on PA fermentations. To demonstrate this, we used the results of 40 Propionibacterium acidipropionici fermentations (ca 2,000 data points) to build up the ANN, and additional two independent fermentations to demonstrate the prediction capability of the observed ANN. Analyzing the predicted output parameters we observed, that ratio of propionic acid to acetic acid (PA/AA) variables can only be used for ANN after normalization. Finally, the fit of the ANN model to the measured data was fine (average correlation coefficients over 0.9). A special feature was also tested: fermentation time was also used as an input parameter, thus making the ANN suitable to predict time course of PA fermentations as well which was also satisfying

Application of a High Cell Density Capacitance Sensor to Different Microorganisms

In microbial cultivations there is a great need for online biomass determination, especially in such cases, where classical methods have limitations. Capacitance-based sensors are developed and widely used in stem cell and other cell cultures [1, 2].In the present study we have tried to apply such a capacitance-based online biomass determination (Incyte, Hamilton AG) for many microorganisms of different types. Since the signal of this sensor is dependent on the polarizability of the measured cells, the applicability of the sensor should be checked for every species. Thus, we developed a method as a preliminary sensor application test which is faster and simpler than testing this sensor directly in real cultivations.We have tested an Incyte sensor with prokaryotic species (Lactobacillus sp., Clostridium) and eucaryotic strains (Saccharomyces cerevisiae, Cryptococcus albidus, Rhizopus oryzae, Chlorella vulgaris, Nannochloropsis oculata). Furthermore, according to our best knowledge this is the first report of a capacitance sensor application for microalgae. Finally, via conductivity measurements of the same sensor, we could even follow product formation in some cases too

Production of the Enzyme Cyclodextrin Glycosyltransferase Using Different Fermentation Techniques

Cyclodextrins produced by cyclodextrin glycosyltransferase (CGTase) are widely used in the pharmaceutical industry to improve the solubility of drug substances as well as protect them against oxidation. The use of this enzyme in the cosmetics industry is also significant. CGTase is an enzyme that belongs to the α-amylase family, which is part of the group of non-Leloir glycosyltransferases. Enzyme-catalysed transglycosylation reactions may involve cyclization, coupling and disproportionation processes. The enzyme CGTase is mostly used to produce cyclodextrins (CDs). CGTase can produce α-, β- and γ-CDs during transglycosylation reactions, depending on the number of glucopyranose units involved (6, 7 or 8). The enzyme CGTase can also be used for enzymatic bioconversion, e.g., in the development of alternative sweeteners, where the bitter aftertaste of the product is reduced during the enzymatic bioconversion of steviol glycosides, thereby obtaining an even sweeter and more advantageous material. In our research, the enzyme CGTase was produced using different fermentation techniques to compare the activity and amount of CGTase produced by each process and optimize the subsequently planned scale-up. In our studies, the strain DSM 13 of Bacillus licheniformis was used, which produced CGTase extracellularly. During the experiments the batch, fed-batch and semi-continuous fermentation techniques were compared in terms of enzymatic production. All cultivation processes were carried out in a desktop lab scale fermenter

Modeling the Biosurfactant Fermentation by Geobacillus stearothermophilus DSM2313

Biosurfactants are emerging molecules in the 21st century. However, their production intensification is still required for the development of feasible bioprocesses. Therefore, this paper studies a new biosurfactant-producer, namely Geobacillus stearothermophilus DSM2313 during statistical optimization via response surface methodology. After the statistical analysis the optimal pH = 7, glucose = 50 g/L and NH4NO3 = 2 g/L concentrations were determined. The biosurfactant production of the bacteria was predicted by our developed artificial neural network. The optimal harvesting time of the broth and the emulsification index values can be predicted simultaneously with the constructed artificial neural network. The best experiment was also kinetically described, and kinetic constants observed. Surface tension and emulsification activity were measured to characterize the formed products' efficiency. Based on these results, biosurfactants from Geobacillus stearothermophilus DSM2313 can act as bioemulsifier and can be applied for example in microbial enhanced oil recovery

Bio-based 3-hydroxypropionic Acid: A Review

3-hydroxypropionic acid is a commercially valuable, important platform chemical. It can serve as a precursor for several key compound, such as acrylic acid, 1,3-propanediol, methyl acrylate, acrylamide, ethyl 3-HP, malonic acid, propiolactone and acrylonitrile. Several microorganisms can produce through a range of metabolic pathways. It is indispensable for the commercial production of 3-HP to use cheap and abundant substrates and also to produce in highly efficient processes which could result high yield, titer and productivity. Because  of the fact, that natural microorganism do not perform these conditions, metabolic engineering and genetically engineered microorganism are widely used for research and production as well. Several metabolic pathways are introduced to utilize glucose or glycerol for 3-HP production. In this overview naturally producer microorganisms, synthetic biochemical pathways, results from the recent years and recovery of 3-HP are detailed