Energieffektiv odling av marina mikroalger vid den svenska västkusten - potentiella applikationer : RISE Rapport 2020: 72

• An energy-efficient cultivation method for microalgae has been further developed for the Nordic climate, specifically for the Swedish west coast. The principle for the cultivation process has earlier been developed by RISE for freshwater microalgae. In this project, we have used marine species, and thereby also seawater, in the cultivation. Utilization of natural seawater lowers the environmental impact since, during some circumstances, freshwater may become limiting even in Sweden. The aim of the study was to investigate if selected marine species could be rotated during the year to achieve a longer cultivation season and increased production of energy-rich algal biomass. Winter, spring and summer at the Swedish west coast were simulated in cultivation experiments in laboratory bioreactors with the species Skeletonema marinoi, usually thriving and blooming on the west coast in winter and spring, and Nannochloropsis granulata, which blooms in summer and produces high amounts of lipids. Nannochloropsis was shown to be more suitable for cultivation during spring and summer, when it comes to production of biomass and energy, while Skeletonema grew better during winter and displayed a higher uptake of phosphate than Nannochloropsis. The productivity of Nannochloropsis was in the same range as that of a previously studied freshwater microalgal species, Tetradesmus obliquus. We have shown the principle for a rotational cultivation strategy and that species adapted for a cold climate can give higher productivity during the cold season. Nevertheless, the selected species (Skeletonema) generally showed too low productivity when cultivated during winter to be energy efficient. More species need to be studied to identify those with a high productivity during winter conditions. Even if cold-adapted species are less productive than the summer-adapted ones, considering the available sunlight, they could still be used to prolong the growth season. The cultivation process of Nannochloropsis could also be optimized in an outdoor environment to prolong the season in different ways, since it was tolerant to cold conditions. In practice, the work-related consequences of a rotational cultivation should be weighed against its benefits for each application. Possible applications mainly include cleaning of air and seawater, production of energy, biomass and biomaterials for the industry.

Ämnesord

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Industriell bioteknik -- Bioenergi (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Industrial Biotechnology -- Bioenergy (hsv//eng)

Nyckelord

Applications

biomass

energy

marine

microalgae

season

Publikations- och innehållstyp

vet (ämneskategori)

rap (ämneskategori)