Microalgae culture collections may contain unexplored strains with great biotechnological potential. Through sampling, identification, characterization, and maintenance of local strains, part of the work described here led to the establishment of the first public Swiss microalgae culture collection, AlgoScope. The potential biotechnological applications of 7 strains from among over 120 native strains were suggested based on growth parameters and biochemical composition. Under standardized growth conditions, Tetradesmus obliquus FAM 27852 and FAM 27855, Chloroidium saccharophilum FAM 27962, Chlorella vulgaris FAM 27965, Stichococcus sp. FAM 27986, Desmodesmus sp. FAM 28090, and Tetranephris brasiliensis FAM 28097 had growth rates of 0.24 d⁻¹–0.80 d⁻¹ and biomass productivities of 0.24 g L⁻¹ d⁻¹–0.73 g L⁻¹ d⁻¹. Proteins, lipids, carbohydrates, and ashes ranged from 32.88 to 53.54%, 9.69–18.08%, 9.32–23.94%, and 3.17–5.51%, respectively. All strains had a similar amino acid composition, containing all essential amino acids. In contrast, the fatty acid composition varied among strains, but, in general, the fatty acids were rich in PUFAs (23.83–53.49% of total fatty acids). Overall, C. saccharophilum FAM 27962 and T. brasiliensis FAM 28097 showed great potential for use in the animal feed sector.

Currently, all feed and food come from plant- or animal-based production systems. The potential of the natural biodiversity of microorganisms for the highly efficient production of nutrients has yet to be leveraged. We present an overarching concept that ranges from the development of a national collection of regional microalgae to the decentralised production of nutrient-rich biomass for animal feed production. The focus is on the substitution of classic plant-based feed to reduce competition for arable land, to increase the nutritive value of animal-based food, and to reduce methane emissions from ruminants. The photoautotrophic and mixotrophic cultivation of microalgae are well aligned with the goals of CO2 fixation and the later contribution to the valorisation of side streams from the food industry. We also present the initial results on strain adaptation to diverse cultivation conditions.

High incidences of the foodborne pathogen Listeria monocytogenes have been reported on smear cheeses, and despite increased hygiene efforts, this incidence has remained stable in recent years. Applying antilisterial strains may increase the safety of smear cheeses. To find and test antilisterial strains, we inoculated fresh soft cheeses from nine dairies with the surrogate species Listeria innocua and assessed its growth under standardized ripening conditions. Acetic acid at day 23 (r = −0.66), lactose in fresh cheese (r = −0.63), and glucose at day 10 (r = −0.62), as well as seven amplicon sequence variants (ASVs), were negatively correlated with L. innocua growth. Two of these ASVs were assigned to the genus Leuconostoc of Lactobacillaceae (r = −0.82 and −0.71). Isolates from this family, from Aerococcaceae, and Carnobacteriaceae were characterized according to their inhibitory properties, and those showing antilisterial properties were applied as protective cultures in challenge tests. The combined application of strains of Leuconostoc mesenteroides, Aerococcaceae, and Carnobacteriaceae successfully eliminated low levels of L. innocua in the final products. This is likely explained by antimicrobial compounds, including mesentericin Y105 and acetate, and competition for carbon sources and iron. This study shows a promising way to improve the safety of soft smear cheeses by applying defined protective cultures.

To boost the local microalgae sector, Switzerland needs to better understand the current state of the industry, which is not fully represented in the existing literature. Only by identifying the strengths and weaknesses of the Swiss microalgae industry, will the country be able to develop strategies toward a strong and sustainable sector in the future. This work provides the first structured assessment of Switzerland’s fragmented and poorly documented microalgae sector through desktop research and an online survey of the country’s microalgae stakeholders. First, research articles with Swiss authors and patents with Swiss applicants were mapped. Then, a survey consisting of 8 questions was designed to gather information about the location, purpose, employees, production capacity, activities, and installations of 42 organizations with a research and/or commercial focus. The growing number of organizations working with microalgae in Switzerland is dominated by small companies (<50 employees) that provide services rather than biomass or bioproducts. Microalgae biomass production is about 2 tons DW per year and is also dominated by small-scale producers (<100 kg DW per year). One third of Swiss companies that sell microalgae-based products produce their own biomass abroad or purchase from abroad. Our findings highlight the growth potential of the Swiss microalgae sector. This systematic summary of research interests, technological innovations, and current market parameters is the first step toward future improvements in the sector.