A bioreactor is used to produce a protein product, and the reaction follows first-order kinetics with a rate constant of 0.02 min^-1. The initial concentration of substrate is 10 g/L, and the reactor volume is 100 L. Determine the concentration of substrate in the reactor as a function of time using Laplace transforms. Then use the inverse Laplace transform to determine the substrate concentration at t = 30 min.