Harnessing Fungal Biotechnology for Space Radiation Protection: Pyomelanin Production from the black mold Aspergillus niger

Abstract

Crewed space missions to the Moon and Mars are major goals of various space-faring nations. However, sending humans farther and longer into space requires sufficient and sustainable protection from cosmic and solar radiation. While Earth's magnetic field shields us from such radiation, space travelers must rely on spacecraft or spacesuit shielding (Norbury et al., 2019). Fungal biotechnology offers significant potential for applied In-situresource-utilization (ISRU) for long-duration space travel, lunar or Martian habitation, and Earth-independent missions (Cortesão et al., 2020b). Among these biotechnological solutions, melanins stand out as promising natural pigments with inherent radioprotective properties, paving the way for their application in future space exploration settings. In this study, we present pyomelanin as a highly radiation-protective pigment derived from the black mold Aspergillus niger. Known for its natural radiation resistance, A. niger serves as an ideal platform for biotechnological exploitation. We demonstrate the production of a novel fungal pyomelanin, termed PyoFun, through inducible overproduction of L-tyrosine in a recombinant ΔhmgA mutant strain (OS4.3). Characterization of PyoFun, along with a synthetic pyomelanin control (PyoSyn), was carried out using UV-Vis, FTIR, and RAMAN spectroscopy, along with physiochemical tests. The antioxidative properties of PyoFun were assessed via DPPH assays. Furthermore, the protective efficacy of PyoFun against monochromatic UV-C radiation was evaluated, showing significant shielding effects against UV-C dosages relevant to space environments (1038 J/m²). The radiation shielding efficiency against ionizing radiation is currently being tested. Our findings suggest PyoFun as a promising biological shield against harmful radiation, particularly relevant for in-situ resource utilization (ISRU) in future space exploration. The extracellular synthesis of pyomelanin eliminates the need for cell lysis during purification. Pyomelanin derived from A. niger holds significant potential for shielding human tissue and spacecraft materials from radiation, emphasizing the need for continued exploration in this critical aspect of space research.