Label-free and gentle separation of cell stages with desired target properties from mixed stage populations are a major research task in modern biotechnological cultivation process and optimization of micro algae. The reported microfluidic sorter system (MSS) allows the subsequent investigation of separated subpopulations. The implementation of a viability preserving MSS is shown for separation of late stage 1 Haematococcus pluvialis (HP) cells form a mixed stage population. The MSS combines a three-step flow focusing unit for aligning the cells in single file transportation mode at the center of the microfluidic channel with a pure hydrodynamic sorter structure for cell sorting. Lateral displacement of the cells into one of the two outlet channels is generated by piezo-actuated pump chambers. In-line decision making for sorting is based on a user-definable set of image features and properties. The reported MSS significantly increased the purity of target cells in the sorted population (94%) in comparison to the initial mixed stage population (19%).
Several methods for the quantitative detection of different compounds, e.g., L‐amino acids, sugars or alcohols in liquid media were developed by application of an automatic measuring unit including a fluid chip‐calorimeter FCC‐21. For this purpose, enzymes were immobilized covalently on the inner and outer surface of CPG (controlled porous glass)‐spherules with an outer diameter of 100 μm and filled into a micro flow‐through reaction chamber (VR = 20 μL). The design of the measuring cell allows for easy insertion into the calorimeter device of a stored series of comfortably pre‐fabricated measuring cells. These cells can be filled with different enzyme immobilizates. Different oxidases were used and co‐immobilized with catalase for the improvement of the detection sensitivity. A signal amplification could be achieved up to a factor of 3.5 with this configuration. β‐D‐glucose, ethanol and L‐lysine could be detected in a range of 0.25–1.75 mM using glucose oxidase, alcohol oxidase and lysine oxidase. The group of oxidases in combination with the enzymatic catalysis of the intermediate H2O2 allows the quantitative detection of a large number of analytes. A good measurement and storage stability could be achieved for several weeks by this immobilization method. In addition to enzyme‐based detection reactions, it was shown that living microorganisms can be immobilized in the reaction chamber. Thus, the system can be used as a whole‐cell biosensor. The quantitative detection of phenol in the range of 10–100 μM could be performed using the actinomycete Rhodococcus sp. immobilized on glass beads by means of embedding into polymers.
The fragility of the benzylic C−H bonds of bis[di(2‐pyridyl)methyl]amine (bdpma) has been demonstrated by a detailed crystallographic study of the wide variety of compounds obtained with the tetrapyridyl ligand and manganese, iron, and cobalt salts (figure).
The microbiological purification of industrial effluents often places high demand on the physiological performance of primary and secondary populations in activated sludges. This particularly applies to combined effluents, originating from different industrial processes, which show frequent fluctuations of effluent composition. Therefore, industrial wastewater treatment plant operators must attempt to permanently monitor the potentially toxic effect of the effluent on process microorganisms. This will enable preventive measures such as storage and/or pre‐treatment of critical batches.
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