Study on optimizing the fermentation of putrescine using Bacillus subtilis 168 engineering strain

Abstract

1,4-Butanediamine (1,4-diaminobutane), an important chemical intermediate, finds extensive application in high-performance nylon, pharmaceutical intermediates, and bio-based materials, among others. As a result, its market demand has been continuously growing. Traditional chemical synthesis methods depend heavily on non-renewable resources and result in significant environmental pollution. Consequently, the advancement of green and efficient biological synthesis approaches has emerged as a prominent research focus. Bacillus subtilis 168, owing to its well-characterized genetic background, diverse molecular modification techniques, and excellent biosafety profile, serves as an ideal platform for the biosynthesis of 1,4-butanediamine. In this study, the fermentation process of the engineered Bacillus subtilis 168 strain was optimized using single-factor experiments and response surface methodology. The results indicated that the optimal fermentation conditions were 8.5 g/L glucose, 12.6 g/L L-arginine, and a fermentation time of 31.8 h, achieving a 1,4-butanediamine yield of 0.782 ± 0.028 g/L. This value closely matched the model prediction, thereby validating the reliability and accuracy of the model. This study offers a solid theoretical and experimental foundation for the industrial production of 1,4-butanediamine.