Plant cell cultures produce active agents for pharmaceuticals, food and cosmetics. However, up to now process control for plant cell suspension cultures is challenging. A positive impact of cell ...immobilization, such as encapsulation in hydrogel beads, on secondary metabolites production has been reported for several plant species. The aim of this work was to develop a method for bioprinting of plant cells in order to allow fabrication of free-formed three-dimensional matrices with defined internal pore architecture for in depth characterization of immobilization conditions, cell agglomeration and interactions. By using extrusion-based 3D plotting of a basil cell-laden hydrogel blend consisting of alginate, agarose and methylcellulose (alg/aga/mc), we could demonstrate that bioprinting is applicable to plant cells. The majority of the cells survived plotting and crosslinking and the embedded cells showed high viability and metabolic activity during the investigated cultivation period of 20 d. Beside its compatibility with the plant cells, the novel alg/aga/mc blend allowed fabrication of defined 3D constructs with open macropores both in vertical and horizontal direction which were stable under culture conditions for several weeks. Thus, Green Bioprinting, an additive manufacturing technology processing live cells from the plant kingdom, is a promising new immobilization tool for plant cells that enables the development of new bioprocesses for secondary metabolites production as well as monitoring methods.
The cultivation of algae either in open raceway ponds or in closed bioreactors could allow the renewable production of biomass for food, pharmaceutical, cosmetic, or chemical industries. Optimal ...cultivation conditions are however required to ensure that the production of these compounds is both efficient and economical. Therefore, high‐frequency analytical measurements are required to allow timely process control and to detect possible disturbances during algae growth. Such analytical methods are only available to a limited extent. Therefore, we introduced a method for monitoring algae release volatile organic compounds (VOCs) in the headspace above a bioreactor in real time. This method is based on ion mobility spectrometry (IMS) in combination with a membrane inlet (MI). The unique feature of IMS is that complete spectra are detected in real time instead of sum signals. These spectral patterns produced in the ion mobility spectrum were evaluated automatically via principal component analysis (PCA). The detected peak patterns are characteristic for the respective algae culture; allow the assignment of the individual growth phases and reflect the influence of experimental parameters. These results allow for the first time a continuous monitoring of the algae cultivation and thus an early detection of possible disturbances in the biotechnological process.
•Uncoupling the light source nature, the system geometry and the microalgae biology is vital in light transfer studies.•Addressing the optical properties of a suspension is critical to know the light ...availability inside a photobioreactor.•The microalgae cell components produce a particular radiant energy field, which holds for the conditions of a unique moment.•This technique is based on an energy balance, and it does not require the knowledge of pigment content.•This study grants an accessible way of evaluating the radiative properties of a suspension for industrial applications.
Regardless if a kinetic expression of a light-dependent bioprocess is being sought, the parameters of that kinetic function are being adjusted, or a scaling-up process is being carried out to predict the productivity of a reactor, it is necessary to know the light availability in the culture volume. The emission characteristics of the radiation source, the geometry of the reactor as well as the optical properties of the suspension that resides within it must be known to achieve the latter. Here, we present an approach to quantify the optical properties of microalgae suspensions. A simple methodology, consisting in illuminating a suspension of microalgae with a characterised polychromatic radiation source and assessing how the directions are modified, and the amount of energy carried by the light beams after crossing the suspension, was successfully employed. Subsequently, through an optimisation program, the experimental culture data has been used to determine the spectral absorption and scattering coefficients of photons, and the suspension's scattering phase function. For a given microalgal culture, eight samples corresponding to a cultivation time of one week were analysed, utilising an energy balance, independently of the biomass or pigment concentration. Altogether the results presented here suggest that this methodology could be adapted to other suspensions, allowing accessible ways to evaluate the radiative characteristics of phototrophic microorganisms in the complex context of the evolution through time of the radiant energy field inside a photobioreactor.
Current global environmental issues raise unavoidable challenges for our use of natural resources. Supplying the human population with clean water is becoming a global problem. Numerous organic and ...inorganic impurities in municipal, industrial, and agricultural waters, ranging from microplastics to high nutrient loads and heavy metals, endanger our nutrition and health. The development of efficient wastewater treatment technologies and circular economic approaches is thus becoming increasingly important. The biomass production of microalgae using industrial wastewater offers the possibility of recycling industrial residues to create new sources of raw materials for energy and material use. This review discusses algae‐based wastewater treatment technologies with a special focus on industrial wastewater sources, the potential of non‐conventional extremophilic (thermophilic, acidophilic, and psychrophilic) microalgae, and industrial algae‐wastewater treatment concepts that have already been put into practice.
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