초록
<P><B>Background</B></P><P>Chemical fertilizers have greatly contributed to the development of agriculture, but alternative fertilizers are needed for the sustainable development of agriculture. 2,3-butanediol (2,3-BDO) is a promising biological plant growth promoter.</P><P><B>Results</B></P><P>In this study, we attempted to develop an effective strategy for the biological production of highly pure <I>R,R</I>-2,3-butanediol (<I>R,R</I>-2,3-BDO) by <I>Paenibacillus polymyxa</I> fermentation. First, gamma-ray mutagenesis was performed to obtain <I>P. polymyxa</I> MDBDO, a strain that grew faster than the parent strain and had high production of <I>R,R</I>-2,3-BDO. The activities of <I>R,R-</I>2,3-butanediol dehydrogenase and diacetyl reductase of the mutant strain were increased by 33% and decreased by 60%, respectively. In addition, it was confirmed that the carbon source depletion of the fermentation broth affects the purity of <I>R,R</I>-2,3-BDO through batch fermentation. Fed-batch fermentation using controlled carbon feeding led to production of 77.3 g/L of <I>R,R</I>-2,3-BDO with high optical purity (> 99% of C<SUB>4</SUB> products) at 48 h. Additionally, fed-batch culture using corn steep liquor as an alternative nitrogen source led to production of 70.3 g/L of <I>R,R</I>-2,3-BDO at 60 h. The fed-batch fermentation broth of <I>P. polymyxa</I> MDBDO, which contained highly pure <I>R,R</I>-2,3-BDO, significantly stimulated the growth of soybean and strawberry seedlings.</P><P><B>Conclusions</B></P><P>This study suggests that <I>P. polymyxa</I> MDBDO has potential for use in biological plant growth promoting agent applications. In addition, our fermentation strategy demonstrated that high-purity <I>R,R</I>-2,3-BDO can be produced at high concentrations using <I>P. polymyxa</I>.</P><P><B>Supplementary Information</B></P><P>The online version contains supplementary material available at 10.1186/s12934-023-02133-y.</P>