Biography

Kari has a PhD in microalgae technology from UiB, with main focus on cultivation technology. The research has emphasis on microalgae for food and feed, where cultivation methods and stress physiology is used as a tool for obtaining algae biomass with composition adapted to specific products. Microalgae as a source of proteins, fatty acids (PUFA) and pigments (such as carotenoids) are important elements. NIBIOs pilot facility for microalgae production at Vollebekk in Ås with large scale photobioreactors, is used for research on upscaling of cultivation methods developed in lab scale, and production of algae biomass for various microalgae product development. In addition, she works with psychrophiles and other microalgae adapted to low temperatures, as a source of bioactive compounds through bioprospecting.

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Abstract

Algal-based wastewater remediation systems (phycoremediation) include phycosphere bacterial communities that influence algal growth, pollutant remediation, and downstream applications of biomass as fertilizers or bio-stimulants. This study investigated the bacterial community dynamics in a novel phycoremediation system using a co-culture of the green algae Stigeoclonium sp. and Oedogonium vaucheri. Bacterial abundance was estimated using flow cytometry (FCM), while community composition was assessed through 16S rRNA gene metabarcoding. Additionally, 28 bacterial strains were isolated from the bioremediation experiment, cultured, genetically characterized for identification and screened for production of the auxin phytohormone indole-3-acetic acid (IAA). Metabarcoding showed that the free-living bacterial community consisted of bacteria from both the wastewater effluent and the algal inocula, while the attached phycosphere community was dominated by bacteria from the algal inocula, indicating the stability of the algae-associated phycosphere. Taxa known to include plant growth-promoting bacteria (PGPB) were abundant, and several strains produced IAA. The bacterial community composition, combined with the potential production of phytohormone by isolated bacteria indicates symbiotic or commensal algae-microbe interactions within the phycosphere bacterial communities. Sterile filtration of wastewater effluent, including only the algal inoculum bacterial communities, reduced algal biomass production and increased bacterial abundance. This study highlights the critical role of microbial interactions in engineered ecosystems and provides insights for optimizing algal-based wastewater treatment technologies.