ALBERT

Description: In the paper "Salinity as a tool for strain selection in recirculating land-based production of Ulva spp. from germlings to adults" (Cardoso et al. 2023) there was a need to compare artificial and natural seawater based on their nutrient composition and concentration. This experiment was performed to guarantee that the results from the other experiments in this paper were not caused by the different types of water, considering that before the start of these experiment the original cultures were growing in natural seawater. The artificial seawater (30 PSU) (Seequasal-Salz, Seequasal Salz Production and Trade GmbH, Münster, Germany) used in this experiment was made in the laboratory at the Alfred Wegener Institute (AWI), Bremerhaven, Germany, right before being analysed. The natural seawater (30 PSU ± 2 PSU) was collected by the Research Vessel Uthörn in the surrounding area of Helgoland, Germany. The process of collection of natural seawater was made every week to refill and supplement the tanks at AWI, Bremehaven. Therefore, the time of the collection and specific location are not known. The nutrient concentration analysis was done in October 2022 at AWI. Before the analysis both water types were pasteurized for 4 hours at 99 °C. The samples collected for analysis were filtered (0.2 µm) (Nalgene®, Nalge Nunc International, USA) and separated into falcon tubes (n = 3). The analysis was performed by an auto-analyser (SEAL Analytical, United Kingdom) and the concentrations of Phosphate, Ammonium, Nitrite and Nitrate were measured.

Description: In the paper "Salinity as a tool for strain selection in recirculating land-based production of Ulva spp. from germlings to adults" (Cardoso et al. 2023) the relative growth rates of germlings of different Ulva species and strains were measured to evaluate the impact of different salinity treatments. We hypothesised that, since their early stages, salinity impacts the relative growth rate of the seaweeds and that different strains are adapted to different salinities. With this data it was possible to use salinity as a tool for selecting the strain with the highest and determine the optimal salinity to grow its germlings under a nursery setting to supplement a large-scale production. Four strains were tested (U. lacinulata and U. linza from the NE-Atlantic and U. lacinulata and U. flexuosa from the Mediterranean). The NE- Atlantic strains were collected in the Óbidos Lagoon, Portugal in January 2021 and were cultivated in laboratory conditions in the Alfred Wegener Institute (AWI), Bremerhaven, Germany. The Mediterranean strains belong to an AWI collection and were isolated in 1986 and 1987 (U. flexuosa and U. lacinulata, respectively). The cultivation of the Mediterranean species with the purpose of using them for experiments started in June 2021. To recreate the conditions of a nursery system, the strains were grown previously and during the experiment in a medium of artificial seawater (Seequasal-Salz, Seequasal Salz Production and Trade GmbH, Münster, Germany) enriched with half-stregth Provasoli (PES; Provasoli 1968; modifications: HEPES-buffer instead of TRIS, double concentration of Na₂glycerophosphate; iodine enrichment following Tatewaki, 1966). Three germlings with similar size from each species and population were placed into multi-well plates and subjected to different salinity treatments (10, 15, 20 and 30 PSU) (n = 3). The germlings were cultivated for 3 weeks. Because of the small size of the germlings, measuring the fresh weight was not possible and, in this experiment, pictures of the germling development were taken every week and the area of the germlings was measured with the software Image J (Rasband 2012). The difference in size was later used to determine their relative growth rate.

Description: In the paper "Salinity as a tool for strain selection in recirculating land-based production of Ulva spp. from germlings to adults" (Cardoso et al. 2023) the antioxidant activity (AA) experiment aimed to test a previously selected strain, Ulva lacinulata from the NE-Atlantic, and evaluate the variations in AA under different salinity treatments. We hypothesized that by reducing the salinity level in the recirculating land-based system, it would be possible to optimize and increase the quality of the biomass being produced before it being harvested. The NE-Atlantic seaweed was collected in the Óbidos Lagoon, Portugal in January 2021 and was cultivated in laboratory conditions in the Alfred Wegener Institute (AWI), Bremerhaven, Germany. To recreate the conditions of a large-scale system, the strain was grown previously and during the experiment in a medium of artificial seawater (Seequasal-Salz, Seequasal Salz Production and Trade GmbH, Münster, Germany) enriched with a cheaper commercial fertilizer Blaukorn (COMPO SANA®, Germany). Twelve 1 L beakers were filled with artificial seawater at 4 different salinities (10, 15, 20 and 30 PSU), measured with a refractometer (Atago, Japan) (n = 3). Six discs (2 cm) of U. lacinulata were placed in each beaker and, at different times (0 h, 3 h, 24 h, 120 h, 192 h and 240 h) 1 disc was collected from each beaker to evaluate the antioxidant activity. The AA was determined by the ABTS Radical Cation Decolourisation Assay based on Re et al., 1999, and a Trolox standard curve was created by measuring the absorption of different Trolox concentrations in ethanol after being mixed with ABTS. The absorption of the samples at 734 nm was analysed with a microplate reader (Infinite 200 Microplate Reader, Tecan Trading AG, Männedorf, Switzerland) and the AA results obtained were given in Trolox Equivalent (in µg/mL).

Description: In the paper "Salinity as a tool for strain selection in recirculating land-based production of Ulva spp. from germlings to adults" (Cardoso et al. 2023) it was evaluated the impact of different nutrient sources on the relative growth rates (RELATIVE GROWTH RATE) of four different Ulva strains during their adult stage. Previously to this experiment, two experiments were performed to evaluate the of germlings and adults of the four Ulva strains. Because the aim of these experiments was to reproduce the conditions of a large-scale production and a small-scale nursery, the adult material was supplemented with a cheaper commercial fertilizer Blaukorn (COMPO SANA®, Germany) while the germlings (in the nursery set-up) were supplemented with half-strength Provasoli (PES; Provasoli 1968; modifications: HEPES-buffer instead of TRIS, double concentration of Na₂Glycerophosphate; iodine enrichment following Tatewaki, 1966). Therefore, this experiment was performed to guarantee that the use of different nutrient sources would not impact the results of the former experiments. Four strains were tested (U. lacinulata and U. linza from the NE-Atlantic and U. lacinulata and U. flexuosa from the Mediterranean). The NE- Atlantic strains were collected in the Óbidos Lagoon, Portugal in January 2021 and it was cultivated in laboratory conditions in the Alfred Wegener Institute (AWI), Bremerhaven, Germany from that moment on. The Mediterranean strains belong to an AWI collection and were isolated in 1986 and 1987 (U. flexuosa and U. lacinulata, respectively). The cultivation of the Mediterranean species with the purpose of using them for experiments started in June 2021. Fresh thalli from each species and population were placed into 1 L glass beakers and subjected to one of the two treatments: water enriched with commercial fertilizer Blaukorn or with half-strength Provasoli (n = 3). The experiment ran for 3 weeks. The fresh weight was measured once a week by collecting the seaweed and removing the excess water with absorbent paper three times before weighing the samples (Sartorius, Germany). Every time, each sample was measured 3 times. Based on the fresh weight measured each week, it was possible to calculate the of each strain throughout the experiment.

Description: In the paper "Salinity as a tool for strain selection in recirculating land-based production of Ulva spp. from germlings to adults" (Cardoso et al. 2023) the relative growth rates of adult thalli of different Ulva species and strains were measured to evaluate the impact of different salinity treatments. We hypothesised that salinity impacts the of the seaweeds and that different strains are adapted to different salinities. With this data we aimed to use salinity as a tool for selecting the strain with the highest and determine the optimal salinity to grow it in the future in a recirculating land-based system. Four strains were tested (U. lacinulata and U. linza from the NE-Atlantic and U. lacinulata and U. flexuosa from the Mediterranean). The NE- Atlantic strains were collected in the Óbidos Lagoon, Portugal in January 2021 and were cultivated in laboratory conditions in the Alfred Wegener Institute (AWI), Bremerhaven, Germany. The Mediterranean strains belong to an AWI collection and were isolated in 1986 and 1987 (U. flexuosa and U. lacinulata, respectively). The cultivation of the Mediterranean species with the purpose of using them for experiments started in June 2021. To recreate the conditions of a large-scale system, the strains were grown previously and during the experiment in a medium of artificial seawater (Seequasal-Salz, Seequasal Salz Production and Trade GmbH, Münster, Germany) enriched with a cheaper commercial fertilizer Blaukorn (COMPO SANA®, Germany). A uniform amount of fresh thalli from each species and population were placed into 1 L glass beakers with salinities of 10, 15, 20 and 30 PSU (each condition n = 3) and cultivated over 3 weeks. The fresh weight was measured once a week by collecting the seaweed and removing the excess water with absorbent paper three times before weighing the samples (Sartorius, Germany). Every time, each sample was measured 3 times. Based on the fresh weight measured each week, it was possible to calculate the of each strain throughout the experiment.

Description: The genus Ulva, described as a good source of antioxidants known for its antibacterial properties and associated with the capacity to adapt to different environments and high growth rates has justified the increasing interest in its large-scale production. While extensive research has been done on optimizing the extraction of Ulva's bioactive compounds, few studies were conducted on increasing or optimizing antioxidant activity of Ulva spp. during cultivation. Our study aimed to investigate an energy-saving cultivation method for optimizing Ulva lacinulata by testing the impact of light dose and light intensity on its antioxidant activity. Two geographically different strains (NE-Atlantic and Mediterranean) were observed for 5 days under two light intensities (70 or 185 µmol photons m-2 s-1) with the same light dose (4 mol photons m-2 d-1). Samples were collected at different times to evaluate the photosynthetic performance (using a Pulse Amplitude Modulated fluorometer). A strain-dependent response was observed between the NE-Atlantic strain and the Mediterranean strain, suggesting that light dose may significantly affect antioxidant activity in certain Ulva spp.

Description: The use of single-use packaging materials has increased dramatically in recent decades in parallel with increasing trends in convenience and fast-food. Most of these packaging materials are made of non-biodegradable, petroleum-based polymers that have degradative impacts on the environment and contribute to the global plastic pollution crisis. Finding alternative packaging materials is an important step towards building a bio-based circular economy. Sustainable land-based macroalgae cultivation can provide a solution, as it eliminates land-use pressure on coastal areas, doesn’t interfere with recreational activities or agriculture, reduces seasonal limitations, allows for complete control over product quality, and ensures consistent quality and traceability. Here, we present the success story of land-based macroalgae production for sustainable packaging solutions in the food industry via the Mak-Pak and Mak-Pak Scale-Up projects

Description: The mission of the Mak Pak Scale Up project 2021 present) is to develop a seaweed based food packaging material and to sustainably scale up the production of seaweed, including Ulva spp in a recirculating land based facility supplemented with artificial seawater that requires a selection and optimization of the seaweed of interest The Ulva genus has previously shown high plasticity and capacity to acclimate and develop under broad ranges of environmental conditions, suggesting this may be a promising candidate for production in a RAS with low salinity artificial seawater Selecting an Ulva strain well adapted to such conditions will help reduce the costs of salt and, therefore, optimize production The aim of this study was to determine how salinity can be used and adapted throughout the entire Ulva production to define several key points 1 strain selection 2 nursery and seeding 3 optimized production in adult Ulva and 4 increasing functionality (e g high antioxidant activity) Based on the results of three different experiments, it was possible to conclude how salinity impacts different strains of Ulva (tubular and blade species) from warm temperate environments, during three key moments of their development and with that, conclude which strains would be more suited to be scaled up within the scope of land based production At the same time, the data presented serve as a baseline for further work with Ulva under different cultivation conditions

Description: Introduction The use of single-use packaging materials has increased dramatically in recent decades in parallel with increasing trends in convenience and fast-food. Most of these packaging materials are made of non-biodegradable, petroleum-based polymers that have degradative impacts on the environment and contribute to the global plastic pollution crisis. Finding alternative packaging materials is an important step towards building a bio-based circular economy. Sustainable land-based macroalgae cultivation can provide a solution, as it eliminates land-use pressure on coastal areas, doesn’t interfere with recreational activities or agriculture, reduces seasonal limitations, allows for complete control over product quality, and ensures consistent quality and traceability. Here, we present the success story of land-based macroalgae production for sustainable packaging solutions in the food industry via the Mak-Pak and Mak-Pak Scale-Up projects. Materials and Methods An initial screening of local macroalgae species was conducted based on detailed knowledge of growth rates, seasonality, geographic range, edibility, iodine content, biochemical properties, bioactivity, robustness and ease of cultivation. Different combinations of selected macroalgae were tested to develop a biodegradable, edible packaging prototype that was rated by consumer tests. In a follow-up project, we are focusing on eliminating the biggest bottleneck: scaling-up biomass production. We have partnered with a local, innovative farmer to sustainably scale-up and optimize biomass production for our sustainable, biodegradable macroalgae-based packaging material for the food industry. Results Several species of suitable macroalgae were selected based on the screening protocol and a method for using different combinations of selected species is described in a patent application for the packaging prototype. The packaging prototype was positively reviewed in consumer tests, where the consumers were pleasantly surprised by the neutral taste and smell. We could also show that certain components of the macroalgae that are important for packaging functionality (e.g. antioxidant activity) could be optimized during land-based production in artificial seawater. Currently we are in the early stages of scaling-up production and selecting strains to optimize growth rates and robustness, where we can complete the life cycle of one selected species from single cells to mature gametophytes within 6 weeks. With controlled induction of reproduction, we can continually provide material for transplantation to large-scale systems. Discussion The Mak-Pak and Mak-Pak Scale-Up projects have been featured in numerous news articles, exhibitions, and podcasts throughout Germany, Europe and even New Zealand. Our experience has shown that there is a lot of public interest in macroalgae-based packaging solutions. Consumers have become aware of the plastic pollution crisis and are open to alternatives to plastic packaging. Consequently, we have recently seen rapid changes in packaging trends in the cosmetic and food industries. Here we show that it is possible to produce a biodegradable, edible packaging from macroalgae biomass for the food-industry. Not only is this a success story for sustainable aquaculture, but also for macroalgae cultivation in general. This project has increased public awareness of macroalgae and contributed to a dialogue about the diversity of products and services that macroalgae can provide as we strive towards a sustainable, circular economy. However, optimization of the raw material production as well as the packaging itself is still underway. Furthermore, limitations in the food-industry require that our raw material meets high quality standards. In other industries where the quality of the raw material is not a limiting factor, there is enormous potential for macroalgae-based packaging solutions.