Medium Optimization by Response Surface Method for Transgenic Synechococcus sp. PCC 7002 with Mouse Metallothionein-I Gene

Abstract:

To implement high cell density cultivation of transgenic Synechococcus sp. PCC 7002 with mouse metallothionein-I gene, and its applications in heavy metal wastewater, we optimized the medium components. We used response surface method, a useful tool for multi-factor process optimization, through a three- step experiment design: full factor design, the steepest climbing and central composite design. The selected three factors were NaHCO3, NaNO3, and initial pH. The optimized medium contained 1.696 g/L NaHCO3 and 8.57 g/L NaNO3, at initial pH 8.57. The optimized medium was validated in 2-L and 20-L air lift photo-bioreactor, respectively. The maximum cell concentration reached 4.16 g/L for 2-L bioreactor, and 3.12 g/L for 20-L bioreactor.