Responses of a new isolated Cyanobacterium aponinum strain to temperature, pH, CO2 and light quality

A new strain of cyanobacteria was isolated from seawater samples collected near Jimo hot springs, Qingdao, China, and was identified as Cyanobacterium aponinum by 16S rDNA analysis. This study examined the effects of temperature, pH, light quality and high CO2 concentration on the growth of the cyanobacteria. Results showed that the strain exhibited a higher growth rate (about 168.4 mg L-1 day(-1)) at 35 A degrees C than other temperatures (surviving at up to 50 A degrees C) and a wide growth tolerance to acidic stress (pH 3.0 to 4.0) resulting from either H2SO4 or HNO3. The four light qualities, ranked by greatest to least biomass effect, were as follows: LED white light (LW) > LED red light (LR) > fluorescent white light (FW) > LED blue light (LB), achieving a higher lighting effect at a LW light intensity (60 mu mol photons m(-2) s(-1)) lower than other light qualities, which implied less energy consumption therewith. This strain demonstrates excellent CO2 tolerance at least 10% CO2 with the highest productivity in biomass (about 337.8 mg L-1 day(-1)) measured at 1% CO2 level. Results indicate that this strain is a promising candidate for use in biofixation of CO2 from flue gases emitted by thermoelectric plants.