Method for co-producing L-isoleucine and L-valine through microbial fermentation

The invention discloses a method for co-producing L-isoleucine and L-valine through microorganisms, and belongs to the technical field of biological engineering. According to the method, threonine is used as a precursor substance for synthesizing L-isoleucine, glucose is fed into the threonine to enable the content of the threonine to be 1-10 g/L, dissolved oxygen of a fermentation system is regulated and controlled in stages, and the dissolved oxygen is maintained at about 30% in the early stage of fermentation to guarantee growth of thalli and synthesis of isoleucine; and in the later stage, the dissolved oxygen is reduced to 10-15%, so that the thalli are fermented to generate more valine, the efficient joint production of the L-isoleucine and the L-valine is realized, and the method has the advantages of high production efficiency and suitability for industrial production. 本发明公开了一种微生物联产L-异亮氨酸和L-缬氨酸的方法，属于生物工程技术领域；本发明中，使用苏氨酸作为L-异亮氨酸合成的前体物质，通过流加葡萄糖使其含量在1-10g/L并分阶段调控发酵体系的溶氧，发酵前期使溶氧维持在30％左右保证菌体的生长以及异亮氨酸的合成，后期降