Fig. 2

Growth curves (a) and fluorescence intensity (b) of BL21AI-GBS, BL21AI-DS, BL21AI-GB, and E. coli BL21AI^TM. Cultures of BL21AI-GBS and BL21AI-DS were divided into two parts when their optical density (OD₆₀₀) was in the range of 0.500–0.800. One part was induced by adding 0.01% arabinose, while the other used as a non-induced control. The optical density and intensity of fluorescence of all cultures were detected every 1.5 h with a spectrophotometer and a fluorescence spectrophotometer, respectively. U and I indicate the uninduced culture and induced culture, respectively