Research On The Carbon Sequestration And Lipid Accumulation Using Microalage

The emissions of CO₂ and other greenhouse gases has aggravated the greenhouse effect,and the energy crisis is threatening the development of human beings.So it is urgent to obtain the highly efficient carbon sequestration technology and new energy.Microalgae,has obtain close attention,not only can absorb and utilize CO₂ effectively,but also can realize the accumulation of lipid,reaching at the dual targets of carbon sequestration and lipid production.In order to explore the feasibility of carbon sequestration and biodiesel making by microalgae,we studied the carbon sequestration and lipid accumulation of microalgae.We get two kinds of microalage by dilution method,one is Cyanobacteria and another is Chlorella.Taking specific growth rate,dry weight increase rate and lipid yield as index,this paper investigated the effects of salinity,pH,inoculum size,light intensity and temperature on growth of above two kinds of microalgae and lipid accumulation by single factor experiment.The results of the study on the effect factors of Cyanobacteria's growth and lipid accumulation of showed that when salinity was 15-25g·L-1,pH was 6-7,inoculum size was 20%,light intensity was 4000 lux and temperature was 25?,the growth condition of Cyanobacteria was better.When salinity was 25g·L-1,pH was 7,inoculum size was 20%,light intensity was 4000 lux and temperature was 25?,the lipid accumulation condition of Cyanobacteria was better.The results of the study on the effect factors of Chlorella's growth and lipid accumulation of showed that when salinity was 5g·L-1,pH was 7,inoculum size was 20%,light intensity was 2000 lux and temperature was 30?,the growth condition of Chlorella was better.When salinity was 15g·L-1,pH was 7,inoculum size was 15%,light intensity was 2000 lux and temperature was 30?,the lipid accumulation condition of Chlorella was better.Taking lipid yield as index,we optimized culture conditions of microalgae according to the results of single factor experiment.The optimization results of Cyanobacteria culture conditions showed that the model regression results between temperature,light intensity and pH were obvious.When pH was 7.06,light intensity was 3850.27 lux,temperature was 25.67?,inoculum size was 20% and salinity was 25g·L-1,the predicted lipid yield of Cyanobacteria was the maximum,reaching 123.656mg·L-1·d-1.The actual lipid yield of Cyanobacteria was 123.802 mg·L-1·d-1 under these conditions.The optimization results of Chlorella culture conditions showed that the model regression results between temperature,salinity and pH were obvious.When temperature was 30.19?,salinity was 15.03g·L-1,pH was 6.99,inoculation size was15%,light intensity was 2000 lux,the predicted lipid yield of Chlorella was the maximum,reacheing 133.036mg·L-1·d-1.The actual lipid yield of Chlorella was 132.812mg·L-1·d-1 under these conditions.Chlorella was sleceted as the subsequent experimental algae.We cultivated the microalgae under the optium conditions,and studied the microalgae's carbon sequenstration ability when CO₂ contents were 10%,20% and 30% respectively,taking specific growth rate,dry weight increase rate and carbon sequestration rate as index.The results of carbon sequestration experiments of microalgae showed that the carbon sequestration rate,specific growth rate and dry weight increase rate of microalgae was highest when the CO₂ content was 30%,which reached 40.78%,0.156d-1,108.9mg·L-1·d-1 respectively.After harvesting the microalgae using UF and flotation coupling microalgae harvesting technology,taking lipid yield as index,we studied the lipid accumulation ability of microalgae.And the lipid yield of microalgae after carbon sequestration reached 116.732mg·L-1·d-1.Such,microalgae has the potential of carbon sequenstration and biodiesel making,and is expected to ease the environmental pressure and energy crisis.