This thesis describes how the abundance of CO2 a ects the porosity of H2O:CO2 ice mixtures deposited at di erent growth temperatures ranging from 30 - 70 K. The mixing ratios of the used ice samples H2O:CO2 = 10:1, 4:1 and 2:1 are of astrophysical relevance. Laser optical interference is used to monitor …

The exploitation of the metagenome for novel biocatalysts by functional screening is determined by the ability to express the respective genes in a surrogate host. The probability of recovering a certain gene thereby depends on its abundance in the environmental DNA used for library construction, the …