Development of Storage Methods for Saccharomyces Strains to be Utilized for In situ Nutrient Production in Long-Duration Space Missions

Date

2017-07-16

Journal Title

Journal ISSN

Volume Title

Publisher

47th International Conference on Environmental Systems

Abstract

Long-duration space missions will benefit from closed-loop life support technologies that minimize mass, volume, and power as well as decrease reliance on Earth-based resupply. A system for In situ production of essential vitamins and nutrients can address the documented problem of degradation of stored food and supplements. Research has shown that the edible yeast Saccharomyces cerevisiae can be used as an on-demand system for the production of various compounds that are beneficial to human health. A critical objective in the development of this approach for long-duration space missions is the effective storage of the selected microorganisms. This research investigates the effects of different storage methods on survival rates of the non-sporulating probiotic S. boulardii, and S. cerevisiae spores and vegetative cells. Dehydration has been shown to increase long-term yeast viability, which also allows increased shelf-life and reduction in mass and volume. The process of dehydration causes detrimental effects on vegetative cells, including oxidative damage and membrane disruption. To maximize cell viability, various dehydration methods are tested here, including lyophilization (freeze-drying), air drying, and dehydration by vacuum. As a potential solution to damage caused by lyophilization, the efficacy of various cryoprotectants was tested. Furthermore, in an attempt to maintain higher survival rates, the effect of temperature during long-term storage was investigated. Data show spores of the wild-type strain to be more resilient to dehydration-related stressors than vegetative cells of either strain, and maintain high viability rates even after one year at room temperature. In the event that engineering the organism to produce targeted nutrient compounds interferes with effective sporulation of S. cerevisiae, a more robust method for improving vegetative cell storage is being sought. Therefore, anhydrobiotic engineering of S. cerevisiae and S. boulardii is being conducted.

Description

Natalie Ball, KBR Wyle, USA
Hiromi Kagawa, Search for Extraterrestrial Intelligence Institute (SETI), USA
Aditya Hindupur, KBR Wyle, USA
John Hogan, NASA Ames Research Center, USA
ICES204: Bioregenerative Life Support
The 47th International Conference on Environmental Systems was held in South Carolina, USA on 16 July 2017 through 20 July 2017.

Keywords

Life support, Nutrients, Microbial Production

Citation