背景:(R,R)-2,3-丁二醇(BDO)在各种应用中使用,并且由于其独特的物理化学特征而变得越来越突出。在肺炎克雷伯菌中使用甘油作为2,3-BDO生产的碳源受到限制,因为1,3-丙二醇(PDO)是在甘油发酵过程中产生的。
结果:在这项研究中,肺炎克雷伯菌budC基因的失活增加了(R,R)-2,3-BDO从21.92±2.10降至92.05±1.20%。肺炎克雷伯菌(内消旋-2,3-BDO)的主要异构体形式转移到(R,R)-2,3-BDO。(R,R)-2,3-BDO通过搅拌速度检查,和98.54%的(R,R)-2,3-BD0在500rpm下获得。然而,随着栽培期的延长,(R,R)-2,3-BDO下降。对于这个问题,两步搅拌速度控制策略(24小时后从500调整到400rpm)和涉及的dhaD基因的过表达(R,使用R)-2,3-BDO生物合成。然而,(R,R)-2,3-BDO仍随时间逐渐降低。最后,当用粗甘油代替纯甘油时,89.47g/L的效价(R,R)-2,3-BDO(1.69g/Lmeso-2,3-BDO),生产率为1.24g/L/h,获得0.35g/g消耗的粗甘油的产率,同时保持98%或更高的纯度。
结论:这项研究很有意义,因为它证明了生产的研究中产量和生产率最高(R,R)-2,3-BDO在克雷伯菌属中具有高纯度。菌株。此外,据我们所知,这是第一个产生(R,R)-2,3-BDO,使用甘油作为唯一碳源。
BACKGROUND: (R,R)-2,3-butanediol (BDO) is employed in a variety of applications and is gaining prominence due to its unique physicochemical features. The use of glycerol as a carbon source for 2,3-BDO production in Klebsiella pneumoniae has been limited, since 1,3-propanediol (PDO) is generated during glycerol fermentation.
RESULTS: In this study, the inactivation of the budC gene in K. pneumoniae increased the production rate of (R,R)-2,3-BDO from 21.92 ± 2.10 to 92.05 ± 1.20%. The major isomer form of K. pneumoniae (meso-2,3-BDO) was shifted to (R,R)-2,3-BDO. The purity of (R,R)-2,3-BDO was examined by agitation speed, and 98.54% of (R,R)-2,3-BDO was obtained at 500 rpm. However, as the cultivation period got longer, the purity of (R,R)-2,3-BDO declined. For this problem, a two-step agitation speed control strategy (adjusted from 500 to 400 rpm after 24 h) and over-expression of the dhaD gene involved in (R,R)-2,3-BDO biosynthesis were used. Nevertheless, the purity of (R,R)-2,3-BDO still gradually decreased over time. Finally, when pure glycerol was replaced with crude glycerol, the titer of 89.47 g/L of (R,R)-2,3-BDO (1.69 g/L of meso-2,3-BDO), productivity of 1.24 g/L/h, and yield of 0.35 g/g consumed crude glycerol was achieved while maintaining a purity of 98% or higher.
CONCLUSIONS: This study is meaningful in that it demonstrated the highest production and productivity among studies in that produced (R,R)-2,3-BDO with a high purity in Klebsiella sp. strains. In addition, to the best of our knowledge, this is the first study to produce (R,R)-2,3-BDO using glycerol as the sole carbon source.