Monitoring of soybean germination process by near-infrared spectroscopy

Soybean seeds were germinated on an industrial scale after soaking for 0–56 h to produce a special additive for food industrial use. The germination process of three soybean varieties was monitored with near-infrared (NIR) spectroscopy based on changes in the amount, status, or character of the water. This paper evaluates the “waterless” NIR spectra of sound, germinated, and heat treated seeds to try to follow the fine details of the germination process. The germination process was analysed with the help of cluster analysis (CA), principal component analysis (PCA), and polar qualification system (PQS) as statistical and chemometric methods. PCA proved to be the most sensitive spectrum evaluation method to follow the fine details of germination. The applied NIR method is suitable for non-destructively, real-time monitoring of the non-linear nature of germination.

Validation of microplastic sample preparation method for freshwater samples

The global presence of microplastics in the environment is well documented nowadays. Studies already showed the potential risks that microplastic particles might cause to the ecosystem, while potential human health effects are currently under investigation. As one of the main inputs of these crucial researches, the concentration of microplastics in the environment should be measured precisely, confidently and monitored regularly to determine exposure levels of these pollutants. Some study highlights, that the results are usually inconsistent and uncertain, due to different sampling and sample preparation methods and the lack of quality assurance and quality control of these processes. The need for a standardized methodology is an emerging issue, as this would provide the right tools to establish a global monitoring system of microplastics. Validated sample preparation methods of water (especially freshwater) samples for microplastic analysis are rarely described. To fulfil the gap, this study aims to create and validate a special toolset and the related standard operating procedure for enhanced sample preparation. A newly developed equipment, the Small Volume Glass Separator was designed to easily isolate microplastics from freshwater samples and concentrate the treated sample in a small volume, thus reducing the brine solution use and the sample transfer steps. These features enable better prevention of contamination and making sample preparation easy, fast and cost-effective. The Small Volume Glass Separator and the related standard operation procedure was validated on model freshwater and wastewater samples with the use of fluorescently tagged microplastics and environmentally relevant microplastics (fragments, fibres). Recoveries were measured with optical microscopy under UV light and with near-infrared spectroscopy/microscopy. Recovery tests with fluorescently tagged microspheres showed that average recovery with the Small Volume Glass Separator is 12-39% higher than that of a widespread sample preparation method. This procedure was also able to recover on average 64%±29% of all the environmentally relevant particles during the validation process. Results show that size and density have a great influence on potential particle loss. Recovery of smaller particles are less with both methods than that of the larger particles, but Small Volume Glass Separator yielded significantly higher recovery for more dense particles. The results of this study help to better understand particle loss during sample preparation and thus contribute to the establishment of standardised microplastic analysis processes.

Validation of pressurized fractionated filtration microplastic sampling in controlled test environment

In the field of microplastic (MP) research in the environment, a significant amount of the currently reported results is uncertain because of the inappropriate methods of sampling, detection and quantification of MPs. Fortunately, many research groups are aware of these challenges, but validated methods, which are the prerequisite of standardized measurements, are scarce. Recovery tests are especially rare in the field of MP sampling. The aim of our research was to take a step forward and collect data on cascade filtration recoveries by modeling different turbulance conditions and sampling depth applying environmentally relevant MP concentrations while obtaining large sample volumes. As reference materials, different polymer types (polyethylene - PE; polypropylene - PP; poly[ethylene terephthalate] - PET; poly[vinyl chloride] - PVC; polyamide - PA) and shapes (sphere, fragment, fiber) were used, and for detection near-infrared spectroscopy/microscopy was applied. The developed method provides information not only on system based MP losses, but on sampling efficiency in a model environment as well. Based on the results, the highest recovery rate of all polymers was 31.4% on average, sampled from the water surface during continuous stirring. In these conditions, 92.4% of the PE spheres and 31.9% of the PE fragments were recovered. This indicates, particles reported in environmental monitoring studies might be less than the real environmental concentration. We can conclude, that surface sampling is more efficient than sampling in a deeper layer of the water column. Our research revealed, that the widespread application of microspheres as reference materials might lead to too optimistic recovery values. The application of reference particles (fragments, fibers) with higher environmental relevance shows much lower recovery rates. Our results highlight, that validating the efficiency of the whole sampling process from the environment is more important than measuring only the filtration device's recovery. This study helps us to better understand the relationship and the possible gaps between the reported MP results and the real-life concentrations in the environment.

Attenuated total reflection fourier transform infrared spectroscopy based methods for identification of chromatography media formulations used in downstream processes

Chromatographic media play a crucial role in the downstream processing of biotechnology products. The physical and chemical properties of these processing aids are mostly monitored by expensive and time-consuming preparative tests, but spectroscopic techniques may also be used to measure chromatographic media samples. In this study, chromatographic media formulations used in downstream processes were investigated using attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy. Samples were measured both in original suspension form and after drying to examine the possibilities of a potential spectroscopic method without sample preparation. Principal component analysis (PCA) was employed to identify the spectral differences among the formulations with distinct support matrices and functional groups and soft independent modeling of class analogy (SIMCA) was performed to creating classification models for identification of chromatography media. To increase the number of samples in the SIMCA, simulated spectra were generated based on the experimental spectra. PCA models indicated that spectra of samples in original suspension form and after drying contained similar information about the chemical properties of chromatographic media samples. Moreover, during the classification of spectra based on SIMCA, both measurement techniques gave high sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) results. These results show that ATR FT-IR could be applied as a simple alternative method for monitoring the chromatography media samples. This technique is also feasible without sample preparation. Thereby the multi-hours drying steps may be omitted, the measurements can be performed in a few minutes, and the potential effects of sample preparations can be eliminated.

Factors Affecting Precipitation of Calcium Lactate from Fermentation Broths and from Aqueous Solution

Lactic acid is one of the most important organic acids which is being extensively used around the globe in a range of industrial and biotechnological applications. Lactic acid can be produced either by fermentation or by chemical synthesis but the biotechnological fermentation process has several advantages compared to the other one. However fermentation broth contains a number of impurities which must be removed from the broth in order to achieve more pure lactic acid. Efficiency of recovery is crucial to the economy of the whole process as well since the costs of separation and recovery are responsible for more than half of the entire cost of production. In the traditional procedure, the heated and filtered fermentation broth is concentrated to allow crystallization or precipitation of calcium lactate, followed by addition of sulphuric acid to remove the calcium in form of calcium sulphate. The disadvantage of this procedure is the relatively high solubility of calcium lactate which causes product loss in the crystallization step. Therefore we investigated the effects of four operating parameters of the crystallization/precipitation process from two different fermentation broths and from an aqueous solution. Thus we applied three central composite statistical designs, in which the examined parameters were the temperature of the solution, the duration of the process, the effect of ethanol addition to the solution as well as the effect of multi-cycle precipitation after separation of the precipitated calcium lactate. According to the results, more than 50 percent calcium lactate precipitation increase can be obtained from fermentation broth by adding sufficient amount of ethanol and adjusting the proper temperature of the process.

Investigation of Differences in the Cultivation of Nannochloropsis and Chlorella species by Fourier-transform Infrared Spectroscopy

The increasing use of energy in the world is leading to the exhaustion of fossil fuels, so novel alternative solutions have to be found to meet our needs. One solution is renewable raw materials extracted from algae. The use of microalgae is widespread, in addition to energy formation, their biomass can also be utilized as food and other valuable components of them, e.g. amino acids, vitamins and minerals can be used in drugs and cosmetics. Due to their boundless diversity and components, they have become the focus of an ever-increasing number of research areas. Different processes can induce changes in their nutritional content, so optimizing the conditions used during their cultivation is important to produce the desired product. In our study different isolates of microalgae, namely Nannochloropsis sp. and Chlorella vulgaris, were studied using Fourier-transform infrared (FT-IR) spectroscopic analysis. Variations in the spectra of a given species were studied under different cultivation conditions.

Method development and qualification of capillary zone electrophoresis for investigation of therapeutic monoclonal antibody quality

Capillary electrophoresis techniques are widely used in the analytical biotechnology. Different electrophoretic techniques are very adequate tools to monitor size-and charge heterogenities of protein drugs. Method descriptions and development studies of capillary zone electrophoresis (CZE) have been described in literature. Most of them are performed based on the classical one-factor-at-time (OFAT) approach. In this study a very simple method development approach is described for capillary zone electrophoresis: a "two-phase-four-step" approach is introduced which allows a rapid, iterative method development process and can be a good platform for CZE method. In every step the current analytical target profile and an appropriate control strategy were established to monitor the current stage of development. A very good platform was established to investigate intact and digested protein samples. Commercially available monoclonal antibody was chosen as model protein for the method development study. The CZE method was qualificated after the development process and the results were presented. The analytical system stability was represented by the calculated RSD% value of area percentage and migration time of the selected peaks (<0.8% and <5%) during the intermediate precision investigation.

Demonstration of an intramitochondrial invertase activity and the corresponding sugar transporters of the inner mitochondrial membrane in Jerusalem artichoke (Helianthus tuberosus L.) tubers

Genetic evidences indicate that alkaline/neutral invertases are present in plant cell organelles, and they might have a novel physiological function in mitochondria. The present study demonstrates an invertase activity in the mitochondrial matrix of Helianthus tuberosus tubers. The pH optimum, the kinetic parameters and the inhibitor profile of the invertase activity indicated that it belongs to the neutral invertases. In accordance with this topology, transport activities responsible for the mediation of influx/efflux of substrate/products were studied in the inner mitochondrial membrane. The transport of sucrose, glucose and fructose was shown to be bidirectional, saturable and independent of the mitochondrial respiration and membrane potential. Sucrose transport was insensitive to the inhibitors of the proton-sucrose symporters. The different kinetic parameters and inhibitors as well as the absence of cross-inhibition suggest that sucrose, glucose and fructose transport are mediated by separate transporters in the inner mitochondrial membrane. The mitochondrial invertase system composed by an enzyme activity in the matrix and the corresponding sugar transporters might have a role in both osmoregulation and intermediary metabolism.

Effect of the degree of substitution of cyclodextrin derivatives on chiral separations by high-performance liquid chromatography and capillary electrophoresis

Optical isomers of some basic racemic drugs (oxprenolol, AMEBD, ephedrine) were separated by high-performance liquid chromatography (HPLC) and/or capillary electrophoresis (CE) using carboxymethyl-beta-cyclodextrin (CMBCD) with various degree of substitution (DS). The effects of the separation conditions (pH, concentration and DS of CMBCD) were studied and compared using CE and HPLC. The degree of substitution had a significant effect on the resolution of the optical isomers and the ionic strength of the separation media, hence the use of well characterized CD derivatives is crucial. Different optimum DS values for the same test samples were obtained when HPLC or CE was used.

Effective sample preparation method for extracting biologically active compounds from different matrices by a microwave technique

A method is described for extracting lupin alkaloid (sparteine) and drug metabolites from different matrices (seeds and rat faeces) using microwave energy and for checking the homogeneity of the electric field in the microwave oven. The high-performance liquid chromatographic separation and determination of the extracted compounds showed that the microwave extraction method is more advantageous than other traditional extraction methods with regard to the yield of extraction and the time and cost of the procedure. The potential degradation of the extracted compounds may be considerably reduced.

Microwave extraction. A novel sample preparation method for chromatography

The applicability of microwave irradiation to the extraction of various types of compounds from soil, seeds, foods and feeds as a novel sample preparation method for chromatography was investigated. Samples were ground and mixed with an appropriate solvent, methanol or methanol-water for polar compounds and hexane for non-polar compounds. The suspensions were irradiated for 30 s, but they were not allowed to boil. After cooling, the irradiation was repeated several times. The samples were then centrifuged, and aliquots of the supernatant were injected into a chromatographic column. The yields of the extracted compounds obtained by microwave irradiation were compared with those obtained by the traditional Soxhlet or shake-flask extraction methods. The microwave extraction method was more effective than the conventional methods. Due to the considerable savings in time and energy, this novel method is suitable for fast extractions of large sample series.