This document summarizes a study on the physiological effects of heavy water (D2O) on the bacterium Bacillus subtilis. B. subtilis was grown in media with increasing concentrations of D2O up to 98% to adapt it. When grown in 89-90% D2O medium, B. subtilis produced 3.9 g/L of deuterated inosine. The study analyzed the qualitative and quantitative composition of cellular proteins, amino acids, and carbohydrates when adapted to D2O. Growing chemoheterotrophic bacteria like B. subtilis in hot mineral water with pH 9-11 was proposed to be more suitable for the origin of life than other water