Betaine is a kind of quaternary ammonium alkaloid, also known as glycine betaine, trimethylglycine, chemical name for N-N-N-trimethyl glycine inner salt. Its chemical structure is similar to amino acid and choline, and its molecular weight is 117.15.

The influence of the increase of betaine on lysine fermentation, the increase of betaine played a promotion effect on lysine fermentation, when the increase of 150-200 mg/L, the promotion effect was obvious, lysine content reached 18.86% (W/V), and the fermentation period was shortened to 41.9 h.  Effect mechanism: Betaine, as an important osmotic buffer in cells, can avoid radical changes in ion concentration.  

Betaine is an important methylation donor, promoting the methylation of the I precursor and then advancing the 1 content.  The effects of betaine on 1 and 2 were investigated by increasing different concentrations of betaine.  Adding betaine to the basal culture base decreases the potency.  (Note: 1 as main product, 2 as by-product).