Colorimetric assay for glucose and lactate

Glucose uptake and accumulated lactate were estimated from the cell-free supernatant using a colorimetric glucose estimation kit and lactate assay kit by slightly modifying the manufacturer’s protocol to adapt for a microtiter plate reader-based readout. Briefly, for glucose uptake assay, 5 µL of cell-free supernatant, 15 µL of distilled water, and 200 µL of the reaction mix were mixed and incubated for 15 minutes at room temperature. Subsequently, absorbance was measured at 340 nm using a Tecan microtiter plate reader. The cell-free supernatant was diluted in the assay buffer in a 1:1000 dilution for lactate assay. 50 μL of the reaction mixture was added to 50 μL of the diluted supernatant and incubated for 30 minutes at 37°C. The absorbance was recorded at 540 nm at an interval of 10 minutes for lactate assay using a Tecan microtiter plate reader.