Abstract：
Residual explosives in conflicting zones have caused irreversible damage to human safety and the environment. Whole-cell biosensors can to detect remnants of buried explosives, such as 2,4-dinitrotoluene (DNT), a stable and highly volatile compound in explosives. However, all the reported whole-cell biosensors utilize fluorescence or luminescence as the biological markers, making their detection difficult in real minefields. Here, we presented a lycopene-based whole-cell biosensor in Escherichia coli to output visible signals in response to DNT, which can help in the visual detection of buried explosives. To construct the whole-cell biosensor, the DNT-responsive promoter yqjF was used as the sensing element, and the lycopene synthetic gene cassette crtEBI was served as the reporting element. Then, the metabolic flux for lycopene production was enhanced to improve the output signal of the whole-cell biosensor, and a terminator was utilized to reduce the background interference. The optimized biosensor LSZ05 could perceive at least 1 mg/L DNT. The DNT-specificity and robust performance of the biosensor under different environmental factors were confirmed. Our results showed that converting the biosensor into a lyophilized powder was an effective storage method. The biosensor LSZ05 could effectively detect DNT in two kinds of soil samples. The lycopene-based whole-cell biosensor could also be used to visually detect heavy metals. Our findings laid the foundation for visually detecting buried explosives in minefields, which was a valuable supplement to the reported biosensors. The methods used for optimizing the lycopene-based whole-cell biosensor, including the improvement of the output signal and reduction of background interference, were quite effective.
摘要：
冲突区域中的残留爆炸物对人类安全和环境造成了不可逆转的损害。全细胞生物传感器可以检测到埋藏炸药的残留物，如2,4-二硝基甲苯（DNT），炸药中的一种稳定且高挥发性的化合物。然而,所有报道的全细胞生物传感器都利用荧光或发光作为生物标记，在真正的雷区很难发现它们.这里,我们提出了一个基于番茄红素的全细胞生物传感器在大肠杆菌输出可见信号响应DNT，这可以帮助视觉检测埋藏的爆炸物。构建全细胞生物传感器,DNT应答启动子YQJF用作传感元件，番茄红素合成基因盒crtEBI作为报告元件。然后，番茄红素生产的代谢通量增强，以提高全细胞生物传感器的输出信号，和终止子被用来减少背景干扰。优化的生物传感器LSZ05可以感知至少1mg/L的DNT。证实了生物传感器在不同环境因素下的DNT特异性和鲁棒性能。我们的结果表明，将生物传感器转化为冻干粉是一种有效的储存方法。生物传感器LSZ05可以有效检测两种土壤样品中的DNT。基于番茄红素的全细胞生物传感器也可用于视觉检测重金属。我们的发现为目视探测雷区埋藏的爆炸物奠定了基础,这是对所报道的生物传感器的宝贵补充。用于优化基于番茄红素的全细胞生物传感器的方法，包括改善输出信号和减少背景干扰，相当有效。
