Low-shear Modeled Microgravity Accelerated the Degradation of Passive Films of Aluminium Alloy by Bacillus Cereus Through Increased Extracellular Polymeric Substances

Microbiologically influenced corrosion (MIC) in water recovery systems with severe microbial contamination in manned spacecraft required attention. The effect of low -shear modeled microgravity (LSMMG) environment on MIC of 5A06 aluminium alloy induced by Bacillus cereus was investigated in this work. Compared with the NG group, the increase of extracellular polymeric substances (EPS) and the occurrence of cell aggregation were the most significant effects of the LSMMG environment through nutrient limitation on B. cereus. And the degradation of passive films of aluminium alloy by B. cereus cells and the increased EPS induced by LSMMG environment was proved through FIB-SEM/TEM and AFM analysis, with thinning passive films and local heterogeneity in charge distribution. The results of this work demonstrate that the LSMMG environment accelerated the degradation of passive films of aluminium alloy through the increased EPS, it meant that microgravity in space would increase the MIC risk of pipeline metals of the water recovery system in manned spacecraft.