High throughput screening of β-glucuronidase (GUS) reporter in transgenic microalgae transformed by Agrobacterium tumefaciens

For this, a new GUS reporter vector pBIN + TetR + TetO was developed, followed by transformation (Agrobacterium tumefaciens), screening and characterization of the transgenic C. vulgaris. In the screening study, strain number 18 showed the highest fluorescence intensity (16,988 ± 1168). The GUS enzyme was found to be stable for >8 h for intact cell and lysed cell studies. The optimum concentration of Triton X-100 to release the product (4-Methylumbelliferone) into buffer was 0.1% and the fluorescence intensity was 28,397 ± 787. The values of Km and Vmax of the recombinant GUS for lysed cells were 0.1304 ± 0.0101 mM and 0.35 ± 0.004 pmol 4-MU/min/ml of crude cell lysate respectively.