| Today, exploring renewable energy has become an inevitable trend to realize sustainable economic and environmental development. Biodiesel is ideal renewable energy that has efficient fuel performance and high flash point, but is non-toxic, with less emission of CO2or sulfur oxides.Microalgae have got more and more attention as one of the best potential feedstocks for biodiesel production due to their high lipid accumulation and various growth characteristics, and as the main primary producers within the phytoplankton have effective carbon sequestration ability to reduce the CO2in the atmosphere. Some Microalgae have the ability to tolerate high CO2concentration that can use the flue gas directly and accumulate biomass and lipid at the same time. However, the conventional methods of cultivating microalgae require large amounts of nitrogen and phosphorus inorganic salts, which lead to the high production costs. It was feasible to cultivate oleaginous microalgae with municipal nutrient-rich wastewater, not only producing feedstock for algal biodiesel, but also removing inorganic nitrogen and phosphorus from wastewater.The objective of our research is to find some marine diatoms that can be cultured with high CO2aeration and municipal nutrient-rich wastewater. Then sdudy the Physiology and Biochemistry mechanism about the marine diatom cultured with that conditions. The main results showed as follows:1. Chaetoceros muelleri MMDL50116, Phaeodactylum tricornutum CCMP632and Thalassiosira pseudonana CCMP1335were cultured with10%CO2aeration, Chaetoceros muelleri MMDL50116and Thalassiosira pseudonana CCMP1335grew well were obtained under10%CO2condition.2. The biomass, total lipid production, maximum CO2bio-fixation rate and fatty acid composition of the marine diatom Chaetoceros mulleri in response to different CO2levels were described. The results showed that the biomass, maximum CO2bio-fixation rate and total lipid contents of the microalgae under 0.03%,10%,20%, and30%CO2levels treatment were0.512,1.022,0.554and0.285g L-1,respectively,0.127,0.428,0.103and0.038g L-1d-1, respectively, and27.74%,43.40%,35.59%and38.51%DW, respectively. The maximum biomass, maximum CO2bio-fixation rate and maximum total lipid contents of the microalgae were all obtained under10%CO2level, indicating that10%CO2concentration was the best condition for the accumulation of biomass and total lipid in our experiment. According to the fatty acid composition analysis, C14:0(>14.41%), C16:0(>19.91%) and C16:1(>37.21%) were the main fatty acid of C. muelleri. These preponderant shorter chain fatty acids (defined as alkyl chains of between12and18carbon atoms long) are significant for their potential as diesel.3. Chaetoceros muelleri MMDL50116, Phaeodactylum tricornytum CCMP632and Thalassiosira pseudonana CCMP1335were cultured in the mix culture medium, which consist of50%municipal wastewater and50%sea water. Only Phaeodactylum tricorntum CCMP632grew well in the novel culture medium.4. Phaeodactylum tricornutum was cultured in Municipal Wastewater:Sea Water medium with the ratio of MW:SW=1:0, MW:SW=1:2, MW:SW=1:1, MW: SW=2:1and MW:SW=0:1. The maximum biomass were obtained in the Municipal Wastewater:Sea Water medium with the ratio of MW:SW=1:1and MW:SW=2:1. The removal percentages of TN, TP and COD in the cultures with the ratio of MW:SW=1:1and MW:SW=2:1after Phaeodactylum tricormutum cultivation were all up to85%. The results indicating that the Municipal Wastewater:Sea Water medium can be used as the medium for Phaeodactylum tricormutum cultivation. |
PDF Full Text Request