Metabolic regulation and optimization of oxygen supply enhance the 2,3‐butanediol yield of the novel <i>Klebsiella</i> sp. isolate FSoil 024

Abstract

Abstract Background Biogenic 2,3‐butanediol (2,3‐BDO) is a high‐value‐added compound that can be used as a liquid fuel and a platform chemical. Bioproduction of 2,3‐BDO is an environmentally friendly choice. Method and Results Three recombinant derivatives of the novel Klebsiella sp. isolate FSoil 024 (WT) were constructed via different strategies including deletion of lactate dehydrogenase by λ‐Red homologous recombination technology, overexpression of the small‐noncoding RNA RyhB and a combination of both. The 2,3‐BDO productivity of the mutants increased by 61.3%–79%, and WT‐Δ ldh /ryhB displayed the highest 2,3‐BDO yield of 42.36 mM after 24 h of shake‐flask fermentation. Glucose was shown as the best carbon source for 2,3‐BDO production by WT‐Δ ldh /ryhB. In addition, higher oxygenation was favorable for ideal product synthesis. The maximal 2,3‐BDO yield of WT and WT‐Δ ldh /ryhB were increased by 23.3% and 52.5% respectively compared to the control group in the presence of 70% oxygen (V:V’ = O 2 :(O 2 + N 2 )). Conclusion and Implications According to the present study, deletion of lactate dehydrogenase, RyhB overexpression, and manipulation of oxygen supply showed great impacts on cell growth, 2,3‐BDO productivity and cellular metabolism of the novel isolated strain Klebsiella sp. FSoil 024. This work would also provide insights for promoting 2,3‐BDO biosynthesis for industrial applications.