Viable cell count of Escherichia coli DH5α in LB Lennox medium supplemented with 2 g/L glucose

Supplementation of growth medium with glucose is a common approach for improving biomass formation given that most microorganisms are capable of utilizing glucose in preference to other carbon sources. LB medium is a common medium for the growth of Escherichia coli, and in this report LB Lennox medium was supplemented with 2 g/L glucose for the cultivation of Escherichia coli DH5α (ATCC 53868). Viable cell count assays were conducted to determine the performance of the medium in supporting an expanded cell population. Experiment results revealed that the glucose supplemented medium was able to support a larger viable cell population of 2.4 x 109 colony forming units (CFU)/mL compared to 1.6 x 109 CFU/mL in LB Lennox medium. Increase in viable cell population during initial growth phase in LB Lennox supplemented with 2 g/L glucose (LBG) was rapid with a 64 fold increase in viable cells in 6 hours. After attainment of maximal viable cell concentration, gradual decline in viable cell concentration was observed, but a significant viable cell population of 2.2 x 108 CFU/mL remained in the culture after 121 hours of incubation. Thus, LBG medium was able to support a larger viable cell population compared to LB Lennox medium. In addition, observation of slow, gradual decline in viable cell concentration during stationary phase revealed that there was no significant secretion of toxic metabolites by the cells during growth in LBG medium. Overall, LBG medium is suitable for use in cultivating E. coli DH5α to higher biomass yield in experiments where a large viable cell population is needed for extended periods.