Explanation
Louis Pasteur (1822–1895) was a pioneering microbiologist and chemist whose work bridged both fields: As a Chemist : Discovered molecular chirality (optical isomers). Studied fermentation, proving it was caused by microorganisms. As a Microbiologist : Developed pasteurization (heat treatment to kill microbes in food). Created vaccines for rabies and anthrax. Disproved spontaneous generation (germ theory of disease).
