A laboratory-based study was undertaken to assess the potential of whey waste as a media for the growth of recombinant Escherichia coli, which remain a preferred choice for process-scale manufacture of many recombinant proteins.
Growth characteristics of a recombinant strain of Escherichia coli (MC1061) was assessed on 2 whey-based media, and compared to growth on standard LB (Luria broth) media, known to achieve high cell densities. Whey-based media were: whey only (WM), and whey mixed with LB media (9:1 ratio; W:LB). Media pH was adjusted to 7 prior to autoclaving.
All experiments entailed media inoculation (100 ml) with 1.0 ml of the recombinant strain (grown in Luria-Bertani broth [LB] to OD600 of 1.5) at 37 °C in a shaking incubator (250 rpm). Growth kinetics and maximum biomass yield was followed by absorbance at 600 nm and dry cell weight determination, respectively.
E. coli growth rates (A600, 6 h cultures, n = 3) were: WM (0.257 ± 0.0448) < W/LB (0.348 ± 0.0246) + LB (1.178 ± 0.0872). Dry cell weights attained after 24 hrs were: WM (4.73 mg ± 0.001387) < W/LB (19.8 mg ± 0.00593) + LB (31.9 mg ± 0.00699).
Un-supplemented whey waste is a poor media for E. coli growth. However, optimally nutrient supplemented whey may yet prove a viable and inexpensive media for E. coli fermentation to high cell densities, converting a potentially waste product into a valuable commodity