High-level production of L-threonine by recombinant with combined feeding strategies.

The process of L-threonine production using TRFC was investigated, and the result showed that there was a large amount of acetic acid in the broth. The effects of acetic acid, which is a known inhibitory metabolite in cultivation, on L-threonine production by recombinant . TRFC were evaluated, and the result indicated that the growth of . TRFC and L-threonine formation were significantly inhibited in the presence of acetic acid. Two combined feeding strategies were applied to L-threonine fed-batch fermentation in order to investigate the effects of the feeding strategy on L-threonine fermentation. The results showed that using the combined feeding strategy of pseudo-exponential feeding and glucose-stat feeding resulted in high cell density (36.67 g L) and L-threonine production (124.57 g L) as well as low accumulation of by-products. This work provides a useful approach for large-scale production of L-threonine.