Experimental Studies On The Optimization Of PH Conditions During Chlorella Vulgaris Culture Process

Now microalgae biodiesel is the research focus of biodiesel industry. Microalgaebecause of its high utility rate of luminous energy, short growth cycle, high unit massoil content, strong environment adaptiveness and good environmental benefits greatlypromote the development of biodiesel. At present the biggest obstacle to hinder thedevelopment of biodiesel are still the production costs. Only reduce its cost ofproduction, the microalgae biodiesel can be more competitive in the market. Aroundthe above goals, the main works of this paper are as follows:(1)Screening microalgae species and medium and determinates the relevant testmethod. In this thesis through research of relevant literature, primary elected threekinds of microalgae species and two kinds of medium as a candidate of theexperiment. Then select Chlorella vulgaris and BG-11medium for this study throughpreliminary culture experiments. And characterization methods of microalgae biomassand lipid accumulation were determined through experiments research.(2)Adjust the pH constant for microalgae culture experiments, and to determinethe most suitable pH range for the growth of Chlorella vulgaris from the perspectiveof biomass accumulation and specific growth rate.(3)Will only adjust the initial pH of for microalgae culture experiments, andcompare the effects of two kinds of adjustment methods on the growth of Chlorellavulgaris, then select the best pH adjustment method.(4)Compare growth conditions of Chlorella vulgaris under different pHdomestication, and verify the impact of autoclaved on uninoculated medium.(5)Preliminary analysis of the application prospects of microalgae cultivationtechnology in comprehensive utilization of sewage, CO2and discharged heat. Andtake a thermal power plant with total installed capacity of1314MW to calculatepotential emission reduction benefits and energy efficiency of microalgae used inCO2fixation.The results showed that the most suitable pH range for Chlorella vulgaris growthis9.5~10.5. In a certain pH range, when only adjust the initial pH, the pH of Algaesolution under different pH levels will be maintained within a certain range. Thisrange is consistent with the optimum pH range for microalgae growth, so it can be used as a basis for judgment of optimal pH. Cell density with constant pH adjustmentis increased by31%than the initial adjustment when the medium pH is10.0, soconstant adjustment better than the initial adjustment. Domesticated experimentalresults showed that, after a pH of10.0domesticated chlorella vulgaris biologicalactivity higher than the pH of7.0domesticated. In the optimum growth pH range, thecell density increased by42.9%, so in the stage of conservation of breeds constantadjustment of the pH is necessary.