Sofia Papadaki

Environmental Assessment of Industrially Applied Drying Technologies for the Treatment of Spirulina Platensis

Spirulina platensis is a high protein content cyanobacterium with known therapeutic properties. Its main protein Phycocyanin is currently as a functional ingredient into various food products to enhance their nutritional qualities acting as food colorant, antioxidant and emulsifier, reducing the use of synthetic additives. The post-harvest treatment of the microalga affects its content of proteins and pigments (carotenois, chlorophylls, etc.), as in the long run the environmental performance of the recovery process. In this study, industrially applied drying techniques, such as Accelerated Solar Drying (ASD) and Vacuum Drying (VD), were examined. The untreated Spirulina biomass showed the highest content in pigments and antioxidant activity, while in the case of dried biomass a significant decrease of the bioactivity was observed. ASD performed better on phycocyanin recovery, while VD showed higher total carotenoids content. Finally, ASD process showed a higher impact in all environmental impact categories, while VD’s cultivation and harvesting stage prior to drying showed significantly higher energy and carbon footprint.

Recovery of Functional Pigments from four Different Species of Microalgae

In the present work, four species of microalgae: Spirulina platensis (SP), Chlorella vulgaris (CV), Haematococcus pluvialis (HP), and the diatom Phaeodactylum tricornutum (PT) were selected as raw materials for the recovery of multifunctional extracts. Ultrasonic assisted extraction (UAE) using different solvents was applied under specific optimized conditions. Organic solvents such as hexane, acetone and ethanol, as well as food grade solvents, such as limonene, MCT oil, soybean oil and phosphate buffer (pH= 7) were used. The total carotenoid, β-carotene and chlorophyll a content in the extracts was determined for all species using UV-Vis spectrometry. Moreover, in the case of SP the phycocyanin content was also measured. The extracts were evaluated regarding their antiradical activity using the DPPH method. Taking into consideration the nature of the solvent used and the total pigment content, acetone and ethanol can be replaced by limonene for the extraction of total carotenoids from HP and PT. For the extraction of phycocyanin from SP, water was considered the most efficient solvent. Ethanol extracts of CV were found rich in β-carotene. The DPPH assay revealed that HP and PT biomass exhibited the highest antiradical activity which can be recovered using suitable solvents.

Effect of drying and extraction conditions on the recovery of bioactive compounds from Chlorella vulgaris

Microalgae and especially green algae are microorganisms that are used in a wide range of industrial applications of high economic interest, such as fish farming, food, cosmetics, pharmaceuticals, and biofuel. In this study, the green microalga Chlorella vulgaris was examined as raw material for the recovery of bioactive compounds and the production of multifunctional extracts. Firstly, the drying of raw biomass, which is a crucial pre-treatment stage, was examined with freeze-drying having the best performance. Ultrasound assisted extraction (UAE) applying various solvent systems was studied under optimized conditions. For the untreated microalgal biomass, ethanol was indicated as the preferable solvent, whereas on dried samples, water was a more suitable solvent. UV-Vis spectrometry and high-performance liquid chromatography (HPLC) were used for the determination of total carotenoid, chlorophyll, and protein content in the raw materials, extracts, and extraction residues. Moreover, the suitability of drying technique and extraction solvent system was evaluated according to the obtained antiradical activity of the relevant treated biomass and extraction samples using the DPPH method.

Effect of Drying Methods on Dyeing Capacity of Dyestuff Plant Materials

This article presents a study of the effect of drying methods on dyeing capacity of widespread European flora dyestuff plant materials. The natural colorants, derived from the selected plant materials, were applied on chemical pulp in order to examine their dyeability. In this work, three different drying methods were examined—the natural, the air-, and the freeze-drying method—in various conditions. The plant materials that were dried naturally show weak dyeing results in comparison with the air- and freeze-dried materials. Freeze drying significantly improved the dyeing capacity of dyestuff plant materials with high initial moisture content. On the other hand, air drying at low temperature and high relative humidity improved the dyeing capacity of plant materials with low initial moisture content.

Assessing the Sustainability of Biomass Use for Energy Production

Abstract Developing sustainable biomass-based bioeconomy applications depends not only on the technoeconomic feasibility of the selected production pathways but also on the management of a multistakeholder system, with, quite often, conflicting stakeholder interests. Developing such applications and their complete lifetime is a long-lasting process, where multiple sectors and actors are involved in diverse levels of decision making. Choosing suitable strategies that will ensure stakeholder engagement in the decision-making process just from the beginning, and where the main actors’ active role will be encouraged through the integration of their views into the final project blueprint, will be a key element of sustainability for any potential project. Therefore a methodological framework for the management of this complexity is presented in this chapter, where the simulation of the proposed methodology for case studies of specific lignocellulosic biomass-based energy applications and its integration in the education of specialists will also be discussed.