Over the last few years the impact of products from natural sources in food, nutraceuticals, cosmetics, flavors/fragrances, and also the pharmaceutical industry has increased due to the consumer demand for nature-derived products. Meeting this demand requires that existing manufacturing processes have to be optimized and process development for a variety of new products, sometimes with short life cycles, has to be accelerated. A scientific literature review covering equipment and modeling for plant-based extractions shows an enormous demand for new approaches in process design for solvent extraction, isolation, and purification of ingredients from botanical sources and its transfer from academic research into manageable solutions for industrial use. An approach combining the design of experiments and rigorous process modeling on the one hand and an intensified collaboration between different disciplines including process engineering, botany, and analytical chemistry on the other hand seems to be the only way forward to address the current issues and shortcomings systematically and efficiently. Hence, a standard apparatus for the assessment of the governing process parameters for plant-based extraction processes is proposed.
A rigorous model supported by botanical investigations has been developed to predict percolation results. Botanical investigations provide needed modeling parameters like pore size, porosity, or target compound distributions over the particle. After determining the desorption isotherm with maceration experiments at different solvent-feed ratios, the model is validated with short residence time percolation experiments. With the aid of this validated model, percolation experiments with long residence times can be predicted and different process scenarios calculated. A combination of design of experiments and rigorous modeling together with standard equipment and experimental model parameter determination provides a fast and robust experimental design on the one hand and the precondition for a process parameter data-based learning curve on the basis of rigorous modeling in the mid-or long-term on the other hand.
The influence of a humid or dry atmosphere on acoustically levitated ionic liquid droplets was studied by volumetric analysis and vibrational spectroscopy. Imidazolium-based ionic liquids with two types of anions, fluorinated (BF(4) and PF(6)) and alkylsulfate anions, were investigated. The amount of absorbed water was correlated with structural differences of the ionic liquids and analyzed in terms of equilibrium mole fraction as well as absorption rate. The type of anion had the most significant influence on the amount of adsorbed water from the atmosphere. Furthermore, spectral changes in the in situ Raman spectra due to absorbed water were studied for all investigated ionic liquids. For 1-ethyl-3-methylimidazolium ethylsulfate, an exemplary detailed analysis of the intermolecular interactions between cations, anions and water was carried out based on the spectroscopic data. The observed band shifts were explained with a hydrogen bond between the anion and water.
A recombinant avidin-producing Mut+ Pichia pastoris strain was used as a model organism to study the influence of the methanol feeding strategy on the specific product productivity (q(p)) and protein glycosylation. Fed-batch cultivations performed at various specific growth rates (micro) and residual methanol concentrations showed that the specific avidin productivity is growth-dependent. The specific productivity increases strongly with the specific growth rate for micro ranging from 0 to 0.02 h(-1), and increases only slightly with the specific growth rate above this limit. N-terminal glycosylation was also found to be influenced by the specific growth rate, since 9-mannose glycans were the most abundant form at low growth rates, whereas 10-mannose carbohydrate chains were favored at higher micro. These results show that culture parameters, such as the specific growth rate, may significantly affect the activity of glycoproteins produced in Pichia pastoris. In terms of process optimization, this suggests that a compromise on the specific growth rate may have to be found, in certain cases, to work with an acceptable productivity while avoiding the addition of many mannoses.
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