Effects of amino acids on the fermentation of inulin or glucose to produce R,R-2,3-butanediol using Paenibacillus polymyxa ZJ-9.

ABSTRACT

This study investigated the effects of different amino acids on the fermentation of pure inulin and glucose using Paenibacillus polymyxa ZJ-9 in order to improve the production of R,R-2,3-butanediol (R,R-2,3-BD) respectively. The inulin extract from Jerusalem artichoke tubers contained 19 common amino acids, which were detected by HPLC. Arg featured the highest content (1290 mg l-1 ). A single add-back experiment of 20 common amino acids indicated that Asn, Ser, His and Arg are key amino acids in R,R-2,3-BD synthesis during inulin fermentation using P. polymyxa ZJ-9. The corresponding yields of R,R-2,3-BD reached 24·32, 22·32, 22·03 and 21·04 g l-1 after the four key amino acids (1·5 g l-1 each) and glucose were evaluated in this fermentation. The yields were considerably higher than that of the control group (12·11 g l-1 ). With the addition of the mixture of four amino acids (1·5 g l-1 each), the highest yields of R,R-2,3-BD (25·07 and 17·47 g l-1 ) were obtained with the increase of 107·0 and 89·1% during the fermentation of glucose and pure inulin respectively. SIGNIFICANCE AND IMPACT OF THE STUDY Paenibacillus polymyxa is a micro-organism with a reported potential for industrialized production of R,R-2,3-butanediol. The nitrogen sources have a significant effect on R,R-2,3-butanediol formation using P. polymyxa. This study demonstrated a highly efficient new method to improve the yield of R,R-2,3-butanediol without adding other nitrogen sources except amino acids during the fermentation. This will therefore decrease the production cost of R,R-2,3-butanediol and provide a new strategy for promoting synthesis of amino acid-dependent products.