Abstract:

        We obtained a strain of oilrich [WTBX]Nitzschia closterium[WTBZ] (BC6) through UVinduction. We further investigated the effects of different culture conditions such as temperature, irradiance, pH value, salinity and nitrogen concentration on its growth. The OD680 and growth rate were determined every two days. Experimental results show that the optimum culture conditions are temperature of 20 ℃, pH value of 7.5, irradiance of 54 μmol·m^-2·s^-1, NaNO₃ concentration of 105 mg·L^-1and NaCl concentration of 27 g·L^-1. Its highest cell density can reach 1.69×10⁶/mL,  2.2 times higher than that of nonoptimization, under these optimal conditions.

Key words: Nitzschia closterium, UVinduction, culture conditions, culture optimization