Question

You do a 10-fold serial dilution of your soil sample in sterile water and plate 1 mL of each subsequent (serial) dilution on LB agar plates with cycloheximide (an antifungal agent). If your 10–6 dilution plate contains 97 bacterial colonies after two days of incubation at 28°C, how many bacteria do you estimate were present in your initial soil sample (1 g of soil)? Show your calculations and briefly describe each step.