Has anyone used the sparkfun special sensor with serial instead of I2C?

EDIT: I meant spectral sensor breakout

I'm trying to figure out if I have to do some redesigns because my current MCU (ATMega32U2) doesn't support I2C or if I can run the sparkfun library with the serial interface? I kind of don't want to get a whole new MCU, but I want to program it using the avr and the ATMega32U2 is so nice for USB interface. Thank you!