| Energy crisis, shortage of water resources, and environmental pollution are the three major problems in the world. With the development of human beings, it is the inevitable choice for human beings to search for clean renewable energy, protect water resources and prevent and control environmental pollution. Biomass energy, as an environmentally friendly renewable energy, has received extensive attention. Among the numerous biomass energy sources, microalgae have become a hot research topic because of their many metabolic pathways, strong environmental adaptability, rapid propagation and high energy content.Phenotype refers to all physical, physiological, biochemical, and biochemical characteristics of the cell structure and composition, and the process of growth and reproduction, as well as the results of the genome and environmental factors. The ecology of microalgae and bacteria in the aquatic environment is complex. As the environment changes, this relationship may also be changed, in turn, the changes in this relationship will affect the environment and change the growth and reproduction of algae.In order to study the influence of commensal bacteria on the phenotypic changes of Chlorella, 6 strains bacteria promoting chlorella growth were isolated and screened fromChlorella broken liquid. Because of promoting Chlorella best z3 bacteria was choosed to be cultured with Chlorella to be studied.In order to study commensal bacteria under the influence of phenotypic changes in Chlorella experiment from C.vulgaris broken liquid isolated and screened 6 strains of chlorella growth promoting bacteria, to promote best Z3 bacteria and Chlorella co culture were studied.16S rRNA sequencing results showed that the homology of z3 bacteria and Bacillus megaterium is 99%. Biolog-GenIII identification results showed that the similarity of z3 bacteria and B. megaterium is the highest.Then z3 bacteria is B. megaterium.It found that the initial inoculum size of B. megaterium had different influences on the growth and reproduction of Chlorella. The experimental results show that when agents of initial inoculum size was 15%(total volume percentage, V / V) can keep B. megaterium and Chlorella shaped into a good long-term mutualism relationship.In order to study the influence of B. megaterium on the antioxidant system of Chlorella, the SOD, CAT and MDA content of Chlorella cell were tested. SOD can clear the active oxygen free radicals in plant cells, CAT can catalyze the decomposition of H2O2, and then eliminate the damage of H2O2 to cells. The content of MDA in cells indicates the damage degree of cells. Experiment results show that SOD and CAT activity of Chlorella in co culture increased first and then decreased, and cell MDA content decreased firstly and then increased, indicating that early B. megaterium in co culture could activate the Chlorella defensive reaction, so as to promote the growth of algal cells, late with the deterioration of the environment, the promotion effect is weakened.In order to study the effects of B. megaterium on carbon source utilization of Chlorella, experimental using Biolog-ECO plate to measure 31 carbon sources utilization of Chlorella in pure culture and co culture, the results showed that carbon sources that was able to be used by the two Chlorella was the same, but the carbon source utilization rate of the two Chlorella was different. The carbon source utilization rate of the Chlorella in co culture was significantly higher than that in pure culture(P < 0.05).It suggests that the effects of B. megaterium on chlorella growth phenotype is not essential, but B. megaterium can help Chlorella better adapt to the organic environment. |
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