Investigating the provision of vitamin B₁₂ in the Micro-Ecological Life Support System Alternative (MELiSSA) loop for long-distance space exploration using algal-bacterial cocultures.
type: CreativeWork
description: Vitamin B₁₂ (cobalamin) is an essential nutrient for humans as it is required as a cofactor for two enzymes involved in central metabolism, methionine synthase and methylmalonyl CoA mutase. It is a corrinoid molecule, composed of a modified tetrapyrrole ring- with a cobalt ion at the centre and various possible upper and lower axial ligands. Vitamin B₁₂ is synthesised only by certain prokaryotes and the process requires over 20 enzymatic reactions. On Earth, most humans fulfil their vitamin B₁₂ requirement through the consumption of meat, eggs, and dairy products all of which would be difficult to source on long-distance space missions. The Micro-Ecological Life Support System Alternative (MELiSSA) project is a long running initiative from the European Space Agency that aims to develop a biological life support system that could enable long-distance crewed space exploration. The MELiSSA project aims to have five interconnected compartments that perform all the necessary life support functions, thereby reducing the volume of initial resources needed for a long-distance mission. The food production compartment (Compartment IV) is split into two sub-compartments, one inhabited by higher plants and the other by the photoautotrophic cyanobacterium *Limnospira indica*. Higher plants do not make, require, or store vitamin B₁₂, and it has been shown that cyanobacteria synthesise a form of vitamin B₁₂, pseudocobalamin, which is less bioavailable for humans than cobalamin. Therefore, the astronauts may be at risk of developing vitamin B₁₂ deficiency during long space missions. This thesis comprises three main sections. Firstly, a novel microbiological assay for the quantification of vitamin B₁₂ is developed, which is able to distinguish between certain lower axial ligands of the vitamin. The novel microbiological assay relies on the ability of the green alga *Chlamydomonas reinhardtii* to remodel pseudocobalamin to cobalamin through switching of the lower axial ligand from ad…
abstract: Vitamin B₁₂ (cobalamin) is an essential nutrient for humans as it is required as a cofactor for two enzymes involved in central metabolism, methionine synthase and methylmalonyl CoA mutase. It is a corrinoid molecule, composed of a modified tetrapyrrole ring- with a cobalt ion at the centre and various possible upper and lower axial ligands. Vitamin B₁₂ is synthesised only by certain prokaryotes and the process requires over 20 enzymatic reactions. On Earth, most humans fulfil their vitamin B₁₂ requirement through the consumption of meat, eggs, and dairy products all of which would be difficult to source on long-distance space missions. The Micro-Ecological Life Support System Alternative (MELiSSA) project is a long running initiative from the European Space Agency that aims to develop a biological life support system that could enable long-distance crewed space exploration. The MELiSSA project aims to have five interconnected compartments that perform all the necessary life support functions, thereby reducing the volume of initial resources needed for a long-distance mission. The food production compartment (Compartment IV) is split into two sub-compartments, one inhabited by higher plants and the other by the photoautotrophic cyanobacterium *Limnospira indica*. Higher plants do not make, require, or store vitamin B₁₂, and it has been shown that cyanobacteria synthesise a form of vitamin B₁₂, pseudocobalamin, which is less bioavailable for humans than cobalamin. Therefore, the astronauts may be at risk of developing vitamin B₁₂ deficiency during long space missions. This thesis comprises three main sections. Firstly, a novel microbiological assay for the quantification of vitamin B₁₂ is developed, which is able to distinguish between certain lower axial ligands of the vitamin. The novel microbiological assay relies on the ability of the green alga *Chlamydomonas reinhardtii* to remodel pseudocobalamin to cobalamin through switching of the lower axial ligand from ad…
author: Harrison, Ellen
language: eng
keywords: Chlamydomonas reinhardtii, Cocultures, Microalgae, Space exploration, Symbiosis
license: https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/c662d95d-b42b-49d8-8377-0135ed432790/download
license: https://www.rioxx.net/licenses/all-rights-reserved/
date published: 2022-11-01
date modified: 2026-07-22T22:24:21Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.99766