| The thesis studied the appropriate culture conditions of Haematococcus pluvialis strain 712, the sensitivity to antibiotics and purification process of algae with antibiotics,the effect of plant hormone on the growth and astaxanthin content of Haematococcus pluvialis, the accumulation of astaxanthin, cell disruption and extraction of crude astaxanthin of Haematococcus pluvialis. The results are as follows:1. Comparision on the difference of growth of Haematococcus pluvialis strain 712 in six different mediums SM, BG-11, HGZ, MCM, SE, BBM on A680,pH of culture liquid,dry weight,astaxanthin content of the algae,and studied the effect of NaNO3,FeSO4,temperature,light intensity and light cycle on it. The results showed that the highest density of cells, dry weight and astaxanthin content of algae culture in HGZ culture were higher than other media.24℃, illuminated continuously under the intensity of 2000 lx, cultured in mended HGZ media is suitable conditions for Haematococcus pluvialis strain 712.2. The results of sensitivity to antibiotics and purification process of algae with antibiotics showed:Haematococcus pluvialis strain 712 was highly sensitive to Gentamycin(Gm), Chloramphenicol(Cm),Tetracycline, and the inhibitory concentrations of Gm, Cm and Tetracycline to Haematococcus pluvialis strain 712 were 10μg/ml, 10μg/ml,50μg/ml separately,but not sensitive to Ampicillin(Amp),Roxit hromycin,and the growth of algae cells could not be inhibited by adding 500μg/ml this two antibiotics separately;the algae cells couldbe inhibited by adding 500μg/ml Levofloxacin lactate. the algae can be purification with the proper concentration of antibiotics mixture as 50μg/ml Amp, 10μg/ml tetracycline, 10μg/ml Gm and 25μg/ml Roxithromycin. After purification,the algae cells can suspend in the liquid medium, and the average growth rate and final cell density of axenic algae cells were higher than the algae nonaxenic.3. The effects of six plant hormone solely and across on Haematococcus pluvialis strain 712 were researched , and the best concentrations and ratio of three kinds of plant hormone which effect on Haematococcus pluvialis strain 712 obviously were elected by Orthogonal test. The results showed that,0.1 ~ 0.5 mg / L 6-BA,0.05 ~ 1 mg / L GA3,0.1 ~ 5.0 mg / L NAA promoted the proliferation,increase of dry weight and astaxanthin content of cells of Haematococcus pluvialis strain 712,of which 0.5 mg / L 6-BA, 0.1 mg / L GA3, 0.5 mg / L NAA could effectively shorten the cycle of cell culture, and improve astaxanthin content of cells of Haematococcus pluvialis strain 712. The results of cross test showed, 2, 4-D cross with GA3, IAA, 6-BA respectively,GA3 cross with NAA and 6-BA were good for proliferation and astaxanthin content of cells of Haematococcus pluvialis strain 712. Results of Orthogonal test showed the better concentration and scale of adding plant growth regulators 6-BA, NAA, GA3 for Haematacoccus pluvialis culture was 0.5:0.1:0.05. 4. By nitrogen deprivation inductive,Haematococcus pluvialis strain 712 could quickly accumulate astaxanthin, the time cells getting red was six days earlier than control experiment,and lead to cell amount reduce at the same time. The effect on astaxanthin accumulation was not significant by Nacl stress inductive; high photon flux density(PFD) inductive could improve the cell transformation rate and reduce the time cells getting red,but excessive PFD did harm to the algae cell,even led algae cells to lose the ability of astaxanthin accumulation. The best PFD for inductive was 7000lx.5. Three Cell-wall breaking methods were compared , and the mortar-grinding was better than ultrasonic, with the freezing-thawing worst. The best solvent for astaxanthin extraction from Haematococcus pluvialis cells was DMSO. The best extraction condition with ultrasonic in DMSO was 200w for 10 minutes.
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