Determination of the biomass, spore count, specific growth rate and doubling time
Aliquots of 5 mL of each medium (per sample flask)
were taken at 2 h intervals during the first 18 h and at
6 h intervals from 18 h to 72 h. To determine the dry
weight of the biomass, 5 mL of each culture was centrifuged
at 7,000 rpm for 25 min. The supernatant was discarded,
and the pellet containing the cells was recovered,
washed three times and dried in a laminar flow
chamber for 72 h. The spore counts were then determined
using a Neubauer chamber (Bing-Lan and Yew-
Min, 2000).