Cultivation of yet unknown microorganisms from extreme aquatic environments

Kurzfassung

Currently less than 1% of microbial taxa discovered (Locey and Lennon 2016), which shows an enormous knowledge gap. The BMBF funded project MultiKulti was started to tackle, by taking aquatic samples from high-altitude Andean lakes in the Atacama Desert, Chile and the biggest cold-water geyser of the world in Andernach, Germany. Those lakes are of special interest due to their extreme conditions, which are important for astrobiologists and the definition of life limits. Organisms isolated from these habitats are well adapted to their environment and have developed diverse survival strategies for stress factors. In this study the tolerance of two bacterial isolates and cyanobacteria will be tested upon temperature, pH, salinity and radiation. The pigmentation of these organisms is of interest, due to its wide use in biotechnological fields and spaceflight as radiation protection. Two organisms were chosen, that showed a 16S rRNA similarity to its closest known relative of less than 98.7%, being the threshold for new species according to Kim et al. 2014. One organism was isolated from Laguna Verde in the Atacama Desert, HP23, which is closest related to Roseovarius tibetensis. The second organism, R23, was isolated from the Geyser Andernach, being closest related to Arundinibacter roseus. Both organisms show a different pigmentation compared to the type strains and their ability to tolerate extreme conditions. This will be tested and compared to the closest relative and the results presented. Further experiments include whole genome sequencing, API tests, fatty acid and polar lipid analysis. Experiments upon their pigment analysis are UV-VIS spectrometry, RAMAN, thin-layer-chromatography, and HPLC-MS. For the radiation shielding experiments organisms will be irradiated with UV light and X-Ray, also the pure pigment extracts will be used as a shield for other organisms. This project will lead to a greater knowledge in the cultivation of extreme microorganisms, their ability to adaption and potential usage in space.