Background: Currently, microbial fe

Background: Currently, microbial fermentation method has become the research hotspot for acetoin production.
In our previous work, an acetoin-producing strain, Bacillus subtilis SF4-3, was isolated from Japanese traditional
fermented food natto. However, its conversion of glucose to acetoin was relatively low. In order to achieve a
high-efficient accumulation of acetoin in B. subtilis SF4-3, main medium components and fermentation
conditions were evaluated in this work.
Results: The by-products analysis showed that there existed reversible transformation between acetoin and
2,3-butanediol that was strictly responsible for acetoin production in B. subtilis SF4-3. The carbon sources,
nitrogen sources and agitation speed were determined to play crucial role in the acetoin production. The
optimal media (glucose·H2O 150 g/L, yeast extract 10 g/L, corn steep dry 5 g/L, urea 2 g/L, K2HPO4 0.5 g/L,
MgSO4 0.5 g/L) were obtained. Furthermore, the low agitation speed of 300 r/min was found to be
beneficial to the reversible transformation of 2,3-butanediol for acetoin production in B. subtilis SF4-3.
Eventually, 48.9 g/L of acetoin and 5.5 g/L of 2,3-butanediol were obtained in a 5-L fermenter, and the specific
production of acetoin was 39.12% (g/g), which accounted for 79.90% of the theoretical conversion.
Conclusions: The results indicated acetoin production of B. subtilis SF4-3 was closely related to the medium
components and dissolved oxygen concentrations. It also provided a method for acetoin production via the
reversible transformation of acetoin and 2,3-butanediol.

Results (English) 3:

背景：目前，微生物发酵法已成为研究的热点，乙偶姻生产。在我们以前的工作中，一个乙偶姻生产菌，枯草芽孢杆菌sf4-3，是从日本传统的分离发酵食品纳豆。然而，其葡萄糖转化为乙偶姻相对较低。为了实现一个在枯草芽孢杆菌sf4-3乙偶姻的高效积累，主要培养基成分和发酵在这项工作中的条件进行了评价。结果：副产物的分析表明，之间存在的乙偶姻和可逆变换2,3-丁二醇，严格负责sf4-3乙偶姻枯草芽孢杆菌生产。碳源，氮源和搅拌决定在乙偶姻生产起到至关重要的作用，是速度。这个最佳媒体·H2O（葡萄糖150 g/L，酵母膏10 g/L，玉米浆干燥5 g/L，尿素2 g/L，K2HPO4 0.5 g/L，硫酸镁0.5 g / L）获得了。此外，低搅拌速度为300 R /分钟被发现是有利于为枯草芽孢杆菌sf4-3发酵生产2,3-丁二醇的可逆变换。最终，48.9 g / L的乙偶姻和5.5 g / L的2,3-丁二醇在5 L发酵罐中获得的，和具体的生产的乙偶姻为39.12%（g/g），占79.90%的理论转换。结论：结果表明，枯草芽孢杆菌sf4-3乙偶姻生产的介质密切相关组分和溶解氧浓度。它也提供了一种用于乙偶姻的生产方法乙偶姻和2,3-丁二醇的可逆变换。