Bioproducts, Sciences and Engineering Laboratory, Washington State University Tri-Cities, 2710 University Dr., Richland, WA 99354-1671, USA.
Appl Environ Microbiol. 2011 Apr;77(7):2399-405. doi: 10.1128/AEM.02341-10. Epub 2011 Feb 4.
To enhance the production of isoprene, a volatile 5-carbon hydrocarbon, in the Gram-positive spore-forming rod-shaped bacterium Bacillus subtilis, 1-deoxy-d-xylulose-5-phosphate synthase (Dxs) and 1-deoxy-d-xylulose-5-phosphate reductoisomerase (Dxr) were overexpressed in B. subtilis DSM 10. For the strain that overexpresses Dxs, the yield of isoprene was increased 40% over that by the wild-type strain. In the Dxr overexpression strain, the level of isoprene production was unchanged. Overexpression of Dxr together with Dxs showed an isoprene production level similar to that of the Dxs overproduction strain. The effects of external factors, such as stress factors including heat (48°C), salt (0.3 M NaCl), ethanol (1%), and oxidative (0.005% H(2)O(2)) stress, on isoprene production were further examined. Heat, salt, and H(2)O(2) induced isoprene production; ethanol inhibited isoprene production. In addition, induction and repression effects are independent of SigB, which is the general stress-responsive alternative sigma factor of Gram-positive bacteria.
为了提高革兰氏阳性孢子形成杆状细菌枯草芽孢杆菌中异戊二烯（一种挥发性 5 碳碳氢化合物）的产量，在枯草芽孢杆菌 DSM 10 中过表达了 1-脱氧-D-木酮糖-5-磷酸合酶（Dxs）和 1-脱氧-D-木酮糖-5-磷酸还原异构酶（Dxr）。与野生型菌株相比，过表达 Dxs 的菌株异戊二烯的产量提高了 40%。在 Dxr 过表达菌株中，异戊二烯的产量没有变化。Dxr 与 Dxs 的过表达显示出与 Dxs 过表达菌株相似的异戊二烯生产水平。进一步研究了外部因素（如热（48°C）、盐（0.3 M NaCl）、乙醇（1%）和氧化（0.005% H₂O₂）应激等应激因素）对异戊二烯生产的影响。热、盐和 H₂O₂诱导异戊二烯的产生；乙醇抑制异戊二烯的产生。此外，诱导和阻遏作用独立于 SigB，SigB 是革兰氏阳性菌的普遍应激响应替代 sigma 因子。
