Control of the lac operon with isopropyl β-d-1-thiogalactopyranoside (IPTG) has been used to regulate gene expression in Escherichia coli for countless applications, including metabolic engineering and recombinant protein production. However, optogenetics offers unique capabilities, such as easy tunability, reversibility, dynamic induction strength and spatial control, that are difficult to obtain with chemical inducers. We have developed a series of circuits for optogenetic regulation of the lac operon, which we call OptoLAC, to control gene expression from various IPTG-inducible promoters using only blue light. Applying them to metabolic engineering improves mevalonate and isobutanol production by 24% and 27% respectively, compared to IPTG induction, in light-controlled fermentations scalable to at least two-litre bioreactors. Furthermore, OptoLAC circuits enable control of recombinant protein production, reaching yields comparable to IPTG induction but with easier tunability of expression. OptoLAC circuits are potentially useful to confer light control over other cell functions originally designed to be IPTG-inducible.

用异丙基β- d -1-硫代吡喃半乳糖吡喃糖苷（IPTG）控制lac操纵子已用于调节大肠杆菌中的基因表达，用于无数应用，包括代谢工程和重组蛋白生产。但是，光遗传学提供了独特的功能，例如易调谐性，可逆性，动态感应强度和空间控制，而化学感应器很难获得这些功能。我们已经开发了一系列用于紫胶光遗传调控的电路操纵子，我们称为OptoLAC，仅使用蓝光就能控制来自各种IPTG诱导型启动子的基因表达。与IPTG诱导相比，将它们应用于代谢工程可将甲羟戊酸和异丁醇的产量分别提高24％和27％，在可扩展至至少两升生物反应器的光控发酵中。此外，OptoLAC电路能够控制重组蛋白的生产，达到与IPTG诱导相当的产量，但表达的可调性更容易。OptoLAC电路可用于对最初设计为IPTG诱导的其他电池功能进行光控制。