The Potential Study Of Leachates Of Saline-alkali Land Leached With Reclaimed Water For Microalgal Cultivation

In the 21st century,the world's energy,environment and food crisis outbreak,microalgae in areas such as energy,food,and environment has great development prospects.But large investment consumption has been the bottleneck to be broken through of industrialization of microalgae.It is necessary to improve the efficiency of microalgae production,and reduce the cost of it.In China,there is a lot of nutrient in 100 million hectares' saline soil areas,which could be used for microalgal growth.In this paper,saline-alkali land was leached with reclaimed water and the leachates were used for microalgal cultivation.This research will provide theoretical foundation and experimental support for the development of coupled technology of water conservancy measures in saline-alkali land management and microalgal higher-value biomass production.The research on algal growth,oil production of Chlorella sp.HQ grown in the leachate of saline-alkali land illustrates that Chlorella sp.HQ has a great growth potential in the leachate of saline-alkali land.L1 and L2(leachates of saline-alkali land)with salt content 0.18%and 0.25%can achieve maximal microalgal density of(15.94±1.49)×107 and(22.69±1.75)×107cells·ml-1,respectively.Moreover,the maximal biomass(409.08±15.12mg·L-1),total lipid yield(240±4.55mg·L-1),total lipid content(58.67±1.65%)were obtained in L2 after cultivation for 45d.According to the comparison of the growth and oil production of Chlorella sp.HQ,Chlorella vulgaris,Scenedesmus sp.LXl,we found that the maximal microalgae densities of Chlorella sp.HQ,C.vulgaris and Scenedesmus sp.LX1 respectively can reach up to(1.65±0.01)×107,(1.41±0.02)×107,(1.22±0.03)×107cells·ml-1.Additionally,the total lipids content per algal biomass of Chlorella sp.HQ reached the highest value of 50.53%.In addition,phosphorus and light source optimization of microalgae grown in saline-alkali land leachate were studied,and the results showed that a small amount of phosphorus addition effectively increase algal cells density,biomass and the total lipids content but not improve triacylglycerols accumulation.Additionally,blue light from LED promoted the algal growth;red light source from LED was beneficial to total lipids accumulation.Different light qualities of LED light sources have great influence for the components of fatty acids of Chlorella sp.HQ.