The Effect of Ionising Radiation on Photosynthetic Oxygenic Microorganisms for Survival in Space Flight Revealed by Automatic Photosystem Ⅱ-Based Biosensors

摘要

Photosynthetic microorganisms are expected to be useful to maintain an oxygenic atmosphere and to provide biomass for astronauts in the International Space Station as well as in future long-term space flights. However, fluxes of complex ionizing radiation of various intensities and energies make space an extreme environment for the microorganisms, affecting their photo synthetic efficiency. To automatically monitor the photo-synthetic Photosystem Ⅱ (PSⅡ) activity of microorganisms under space conditions an optical biosensor, which utilizes chlorophyll fluorescence as biological transduction system, was bui the PSⅡ activity was monitored by the biosensor during balloon flights at stratospheric altitudes of about 40 km. The effect of space stress on quantum yield of PSⅡ varied among the tested species depending on the growth light conditions at which they were exposed during the flights.