中国生物工程杂志

Photoautotrophic gametophyte cells of the brown macroalgae Laminaria japonica were cultivated in 500 mL stirred tank photobioreactors under seven pulse feeding modes and one batch mode. It is the first time for the study of effects of the feeding time points and feeding quantity on macroalgal cell growth and nutrient consumption. Results showed that, with inoculum density of 50 mg DCW L-1, in modified APSW artificial seawater medium at 13 ℃, light intensity of 60 ?E m-2 s-1, light cycle of 16/8 h L/D, aeration rate of 50 mL min-1, and agitation speed of 100 rpm, feeding the culture with small nutrient quantity was beneficial for the synchronization between nitrate and phosphate absorption, and further for biomass production. Feeding when ambient nutrient was abundant or depleted was quite weak for large amount of biomass accumulation, which might be due to the slowing nutrient absorption, nutrient storage, or the divergence absorption between nitrate and phosphate. Feeding nutrient frequently with small quantity from mid-exponential growth of macroalgal cells, that is maintaining medium nutrient concentration between 1/3 and 1/2 of its initial concentration in this paper, was the most effective way for biomass production, with biomass increased by 12.270 times of for 51 days' cultivation.