Isolation Of High-lipid Microalgae And Study On The Properties Of Lipid Production In Reclaimed Water

Water resource crisis and energy crisis are the two major challenges in the 21st century. Water reuse technology and new energy development are effective approaches solving these challenges.In recent years, using microalge to remove nitrogen/phosphorus in tertiary treatment and produce biodiesel has made rapid progress. However, each of the two systems has its own limit. Based on that, the concept of"coupling the wastewater advanced treatment and high lipid algae production"was built, the algal growth potential of waster water was investigated, 3 strains high-lipid algae was isolated, and the growth, lipid production and TN/TP removal properties was studied.Algal growth potential test showed that: the secondary treatment unit increased the algal growth potential of wastewater, and the secondary effluent had advantage in algae cultivation.Using dry weight and lipid content as indexes, 3 strains of algae was isolated from 14 candidates and showed their advantages in growth, lipid production and TN/TP removal abilities in secondary effluent. Among them, Haematococcus pluvialis had advantages in specific growth rate, maximum growth rate of dry weight, lipid content and lipid production rate. The effect of environmental factors on the growth and lipid accumulation abilities of Haematococcus pluvialis were studied. Results showed that: (1) LED's red/blue light had enhancing effect on growth and total lipid production of Haematococcus pluvialis; (2) ammonia in secondary effluent increased the specific growth of Haematococcus pluvialis, but decreased dry weight, dry weight growth rate and total lipid production; (3) initial concentration of TN/TP in secondary effluent had little effect on specific growth rate, but had obvious effect on maximum dry weight (Gmax) and maximum dry weight growth rate (Rmax). The effect of initial concentration of TN/TP on Gmax and Rmax of Haematococcus pluvialis can be described with Monod equation; (4) initial inoculums had little effect on the maximum dry weight of Haematococcus pluvialis, but had decreasing effect on specific growth rate and maximum dry weight growth rate. Haematococcus pluvialis with high initial inoculums could get high lipid content and total lipid production in short time, hence had shorter time for cultivation.