S. Rahul, G.K. Suraishkumar
Indian institute of technology Madras,
India
Keywords: In-space biomanufacturing, Halobacterium, Bacteriorhodopsin, Oxidative stress, Reactive oxygen species, simulated microgravity.
Summary:
Biological production in microgravity offers potential benefits; however, the effect of microgravity on microbial growth and metabolism varies across species, and its underlying mechanism remains unclear. A better understanding has significant implications for both fundamental research and applied biotechnology. Reactive oxygen species (ROS), such as hydroxyl radicals, nitric oxide, and superoxide, play crucial roles in cellular signaling and defense mechanisms, and their intracellular pseudo-steady-state levels are now accepted as reliable markers of cellular oxidative stress. Our previous studies have demonstrated that ROS can enhance microbial productivity by more than 400%. Yet, under microgravity conditions, their effects are poorly understood. This study focuses on understanding the impact of oxidative stress on the cellular metabolism of Halobacterium salinarum under simulated microgravity conditions. The aim is to enhance in-space biomanufacturing outcomes by modulating cellular reactive species homeostasis. Our model system is the H. salinarum, known for its production of bacteriorhodopsin, a photosensitive transmembrane protein with diverse applications, including the in-space development of improved artificial retinas. We explore the ROS and their impact on H. salinarum cellular metabolism under varying gravity conditions, utilizing a Rotatory Cell Culture System (RCCS) for experimental studies and metabolic modeling techniques. Preliminary findings reveal an 18% reduction in maximum cell concentration under simulated microgravity compared to normal gravity (1g) conditions. We are focusing on oxidative stress based reasoning for this change by investigating various components of cellular redox homeostasis, like ROS and antioxidants. Further study involves modulating cellular ROS levels and analyzing growth and productivity under different gravity conditions. By integrating these analytical approaches, our study aim is to devise a novel ROS based strategy to enhance productivity in the in-space biomanufacturing of microbial products. Understanding the complex interplay between microgravity, oxidative stress, and microbial metabolism holds significant promise for advancing biotechnological applications in space exploration and utilization.