Genome and transcriptome analysis of Bacillus velezensis BS-37, an efficient surfactin producer from glycerol, in response to d-/l-leucine
Genome and transcriptome analysis of Bacillus velezensis BS-37, an efficient surfactin producer from glycerol, in response to d-/l-leucine
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贝莱斯芽孢杆菌 BS-37 的基因组和转录组分析（一种高效的甘油表面活性素生产者）对 d-/l-亮氨酸的反应
DOI：
10.1002/mbo3.794
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发表时间：
2019
期刊：
影响因子：
3.4
通讯作者：
Li Shuang
中科院分区：
文献类型：
--
作者：
Zhou Dayuan;Hu Fangxiang;Lin Junzhang;Wang Weidong;Li Shuang
表面活性剂因其在不同领域的许多潜在应用而成为研究最广泛的生物表面活性剂之一。在本研究中，贝莱斯芽孢杆菌 BS-37 最初被鉴定为枯草芽孢杆菌菌株，通过添加甘油（一种生物柴油生产的廉价副产品），可有效生产表面活性剂。在甘油培养基中生长36小时后，总表面活性素浓度达到1,000 mg/L以上，是蔗糖培养基中的两倍。此外，向培养基中添加右旋亮氨酸和右旋亮氨酸对 BS-37 的表面活性素产生具有相反的影响。虽然添加 10 mMl-Leu 后表面活性素产量显着增加至近 2,000 mg/L，但添加 10 mMd-Leu 后表面活性素产量显着降低至约 250 mg/L。为了系统地阐明影响该生物合成过程效率的机制，我们对 BS-37 的基因组进行了测序，并分析了甘油培养基中转录组响应 tod-/l-亮氨酸的变化。对BS-37转录组的RPKM分析显示，编码模块化表面活性素合酶、甘油利用途径和支链氨基酸（BCAA）合成途径的基因的转录水平均处于较高水平，这可能解释了该菌株为何能够高效利用甘油高产地生产表面活性素。 1-Leu 和 d-Leu 对这些途径中基因的表达均没有显着影响，表明 1-Leu 作为参与表面活性素产生的前体或底物发挥着重要作用，而 d-Leu 似乎充当竞争性抑制剂。本研究结果为表面活性素的合成及其调控方式提供了新的见解，丰富了高产菌株构建的基因组和转录组资源。
Surfactin is one of the most widely studied biosurfactants due to its many potential applications in different fields. In the present study,Bacillus velezensisBS‐37, initially identified as a strain ofBacillus subtilis, was used to efficiently produce surfactin with the addition of glycerol, an inexpensive by‐product of biodiesel production. After 36 hr of growth in glycerol medium, the total surfactin concentration reached more than 1,000 mg/L, which was two times higher than that in sucrose medium. Moreover, the addition ofl‐ andd‐Leu to the culture medium had opposite effects on surfactin production by BS‐37. While surfactin production increased significantly to nearly 2,000 mg/L with the addition of 10 mMl‐Leu, it was dramatically reduced to about 250 mg/L with the addition of 10 mMd‐Leu. To systemically elucidate the mechanisms influencing the efficiency of this biosynthesis process, we sequenced the genome of BS‐37 and analyzed changes of the transcriptome in glycerol medium in response tod‐/l‐leucine. The RPKM analysis of the transcriptome of BS‐37 showed that the transcription levels of genes encoding modular surfactin synthase, the glycerol utilization pathway, and branched‐chain amino acid (BCAA) synthesis pathways were all at a relatively high level, which may offered an explanation why this strain can efficiently use glycerol to produce surfactin with a high yield. Neitherl‐Leu nord‐Leu had a significant effect on the expression of genes in these pathways, indicating thatl‐Leu plays an important role as a precursor or substrate involved in surfactin production, whiled‐Leu appears to act as a competitive inhibitor. The results of the present study provide new insights into the synthesis of surfactin and ways of its regulation, and enrich the genomic and transcriptomic resources available for the construction of high‐producing strains.