Establishing land tank cultivation of Asparagopsis taxiformis in Scotland

Abstract

Asparagopsis taxiformis is a high-profile rhodophyte due to proven effects in reducing methane emissions in ruminants up to 98%. Methane from agricultural production of ruminants is responsible for ~25% of global methane emissions. Interest and demand for facilitating production of Asparagopsis taxiformis has driven research into developing methods to grow it in tanks, terrestrially. In regions where it is a non-native species, potentially, it will be unable to survive under the prevailing conditions, and there may also be issues with introduction to open environments. Research has focussed on tank cultivation of the tetrasporophytic stage of Asparagopsis sp. Research has identified the key antimethanogenic component within biomass of Asparagopsis sp. is a halogenated metabolite, bromoform. It is theorised that the respective life stage of different lineages of A. taxiformis produces different concentrations of bromoform and this is related to cultivation conditions. This thesis focused on vegetative growth and biochemical composition of the gametophytic stage of A. taxiformis, Lineage 2 (CCAP 1341/1), in a series of commercially available photobioreactors analogous to land-based tanks. Photobioreactors were set to observe growth and biochemical content in comparable natural conditions of Scotland and its native region, Naples, Italy. The first photobioreactor, Algem, showed that the growth conditions in the native region were preferable for increasing biomass yield. The second photobioreactor, CYCLOPS, did not reflect the previous experimental findings. Variances were found in biochemical content of the material produced from either photobioreactor experiment. It was indicated that iodine content, cited as potentially being at toxic levels in wild-type biomass, was ~50-80 times less. The analysis of bromoform content in any of the biomaterial was unsuccessful, with reasons later identified. This project demonstrated that cultivation of the gametophytic stage of A. taxiformis in closed culture systems is viable, with methods to analyse and sustain bromoform content needing refinement.

Date of Award	2 Mar 2023
Original language	English
Awarding Institution	University of the Highlands and Islands
Supervisor	Michele Stanley (Supervisor) & Valeria Montalescot (Supervisor)