The betaine biosynthesis system in bacteria is a crucial pathway that produces betaine, a key osmoprotectant that helps cells survive in high-salinity or osmotic stress conditions. Bacteria typically synthesize betaine from choline through a two-step oxidation process. The first step is catalyzed by choline dehydrogenase, which converts choline into betaine aldehyde, and the second step involves betaine aldehyde dehydrogenase, which oxidizes betaine aldehyde into glycine betaine. In some bacteria, such as *Bacillus subtilis*, betaine can also be synthesized from glycine via methylation steps catalyzed by glycine methyltransferases. Glycine betaine functions by stabilizing proteins and cellular structures without interfering with cellular metabolism, making it an effective osmolyte. Additionally, many bacteria can import choline or betaine from their environment using high-affinity transport systems when external sources are available. This biosynthesis pathway is critical for bacteria to adapt to osmotic stress in diverse habitats, including soil, marine environments, or host tissues, thereby enhancing their ecological fitness and survival.

Betaine biosynthesis References