Jiangnan University, Wuxi, Jiangsu, China.
J Ind Microbiol Biotechnol. 2010 Feb;37(2):179-86. doi: 10.1007/s10295-009-0661-5. Epub 2009 Nov 11.
A spore-forming Bacillus sp. was isolated from a high-temperature Daqu, a starter culture of Chinese Maotai-flavor liquor, using an endogenous precursor screening strategy. The Bacillus sp. was capable of producing a high level of 2,3,5,6-tetramethylpyrazine (TTMP) via a precursor of 3-hydroxy-2-butanone (HB). The strain was characterized as Bacillus subtilis based on morphological, physiological, and biochemical properties as well as on partial 16S rRNA gene sequences. Different carbon and nitrogen sources as well as fermentation conditions were investigated. Optimization tests showed that oxygen supply and fermentation temperature were the most important parameters determining the production process. The production of >4.08 g/l TTMP was achieved together with a high level of endogenous precursor HB accumulation (>20 g/l) in both flask and fermentor cultures when the optimized medium and cultivation conditions were applied. Our data demonstrates the effectiveness of the endogenous precursor strategy for screening microorganisms that produce flavor compounds with structure-related precursors. The high yield of TTMP and the inexpensiveness of the agro-industrial product used as the substrate (soybean meal) indicate the potential of this process for industrial application.
采用内源前体筛选策略，从高温大曲（中国茅台酒风味白酒的起始培养物）中分离出一种产孢芽孢杆菌。该芽孢杆菌能够通过 3-羟基-2-丁酮（HB）的前体产生高水平的 2,3,5,6-四甲基吡嗪（TTMP）。根据形态学、生理学和生物化学特性以及部分 16S rRNA 基因序列，该菌株被鉴定为枯草芽孢杆菌。研究了不同的碳源和氮源以及发酵条件。优化试验表明，供氧和发酵温度是决定生产过程的最重要参数。当应用优化的培养基和培养条件时，在摇瓶和发酵罐培养中均实现了>4.08 g/l TTMP 的高产，同时内源前体 HB 的积累水平也很高（>20 g/l）。我们的数据证明了内源前体策略在筛选具有结构相关前体的风味化合物产生微生物方面的有效性。TTMP 的高产量和作为底物的农业工业产品（豆粕）的廉价性表明该工艺具有工业应用的潜力。
