Pickles have been an important part in the worldwide diet for a long time. But the nitrite generated in the production of pickles has always been a concerning problem to health and food safety, due to its conversion to carcinogenic nitrosamine once taken up by humans. Currently, most industrial production of pickles relies on the natural decomposing process of nitrite, which is inefficient and often takes months to complete. To make an improvement, we designed a bio-device to make the degradation of nitrite rapider and more environmental-friendly. Our device consists of a positive feedback loop followed by a fusion enzyme which can reduce nitrite to nitrogen and oxygen. The feedback loop is regulated by a nitrite/nitrate specific promoter to ensure the expression of downstream function proteins only in pickles environment. Our solution drastically shortens the production period and increases profit margin for the multibillion-dollar pickled vegetables industry.