不同磷浓度对螺旋藻砷吸附、吸收及转化的影响研究

发布时间：2018-05-12 19:15

本文选题：螺旋藻 + 磷酸盐　；参考：《南京农业大学》2015年硕士论文

【摘要】：螺旋藻被誉为"21世纪最理想的食品"。随着保健品的生产和开发,螺旋藻的安全品质越来越受到人们的关注。近年来,我国部分品牌的螺旋藻保健品中发生了砷(As)含量超标事件,开展螺旋藻砷污染控制的研究已非常紧迫。以往这方面的研究大多集中在藻粉中总As含量的检测和螺旋藻As污染源的分析。有关磷(P)浓度如何影响螺旋藻吸附、吸收和转化砷酸盐As(V)、亚砷酸盐As(Ⅲ)的研究仍鲜有报道。本试验以钝顶螺旋藻为研究对象,首先用不同浓度As(Ⅴ)、As(Ⅲ)处理螺旋藻7 d,研究藻体对As的吸附和吸收特性;然后降低培养液中P浓度,研究不同P浓度对螺旋藻生长的影响;在藻体生长不受影响的情况下,研究不同P浓度对螺旋藻As(Ⅴ)、As(Ⅲ)吸附、吸收及胞内As形态的影响。主要研究结果如下:1.不同P浓度对螺旋藻生长的影响采用实验室内培养,设置系列P浓度(1/200P正～P正,P正为正常P供应时培养基中P的浓度88.9mg·L~(-1))处理,研究不同P浓度对螺旋藻生物量、藻胆蛋白、叶绿素含量的影响。结果表明,与P正相比,1/10、1/25、1/50P正对螺旋藻的生长没有影响;当P浓度降低时1/100P正时,藻体藻胆蛋白显著降低,叶绿素含量增加;当P继续降低至1/200P正时,螺旋藻的生物量、藻胆蛋白、叶绿素含量降低,生长受到显著影响。2.不同浓度As(Ⅴ)、As(Ⅲ)对螺旋藻生长、As富集的影响分别用不同浓度 As(V)(50、100、150、200、250、300 μg·L~(-1))、As(Ⅲ)(50、100、200、300 μg·L~(-1))处理螺旋藻,比较不同As处理对螺旋藻生长和As吸附、吸收特性的影响。研究结果表明,与无As处理的对照组相比,不同浓度As(Ⅴ)对螺旋藻的生物量几乎无影响,As(Ⅲ)处理的藻体生物量有增加的趋势,但变化不显著。螺旋藻As吸附量、吸收量和总砷含量均随着培养液中As处理浓度的升高显著增加。在相同As处理浓度下,As(Ⅲ)处理的藻体As吸收量和总砷含量均比As(V)处理的藻体高,而As吸附量相差不大。50、100 μg·L~(-1) As(Ⅴ)处理的螺旋藻几乎不吸收As,As(Ⅲ)处理的藻体As吸收量分别为0.242、0.300 mg·kg~(-1)。因此,在相同As浓度处理时,螺旋藻对As(Ⅲ)的富集能力更强。此外,当培养液中As(Ⅴ)浓度达到150 μg·L~(-1)时,藻体富集的As含量为1.006 mg·kg~(-1)，超过了我国保健品中As的限量值1.0 mg·kg~(-1)。As(Ⅲ)处理浓度为 200 μg·L~(-1)、300 μg·L~(-1),藻体总砷含量为 1.471 mg·kg~(-1)、2.285 mg kg~(-1)，严重超过标准限量。但大部分的As被吸附在细胞表面,因此可以通过PBS洗脱明显降低藻体的总砷含量。此外,As(Ⅴ)处理时螺旋藻胞内只有As(Ⅴ)一种As形态,而As(Ⅲ)处理的藻体胞内同时存在As(Ⅲ)和As(Ⅴ),但以后者为主要形态。3.不同P浓度对螺旋藻吸附、吸收和转化As(V)、As(Ⅲ)的影响设置在不影响螺旋藻正常生长的P浓度(1/50P正～P正),分别用As(Ⅴ)(300 μg·L~(-1))、As(Ⅲ)(200、300 μg·L~(-1))处理螺旋藻,研究比较不同P浓度对螺旋藻As(Ⅴ)、As(Ⅲ)吸附、吸收和胞内As形态的差异。研究结果表明,正常P条件下，300 μg·L~(-1)As(Ⅴ)、As(Ⅲ)处理的藻体吸收As含量分别为0.202、0.802 mg kg~(-1);当P浓度为1/25 P 正时,藻体As吸收量分别显著增加至1.369、2.181 mg kg~(-1);P降低至1/50P正藻体吸收的As含量继续增加至1.457、2.672 mg-kg~(-1),表明降低培养液中P的浓度会促进藻体对As的吸收,增加了螺旋藻As污染超标的风险。此外,用As(V)处理螺旋藻后,培养液中P浓度的降低还会促进螺旋藻胞内As的还原、甲基化和外排过程。当用As(Ⅲ)处理时,螺旋藻对As(Ⅲ)具有较强的氧化作用,降低培养液P浓度也促进了上述过程的发生。在300 μg· L~(-1)As(Ⅴ)处理下,仅当P浓度降低至1/50P正时,螺旋藻胞内产生二甲基砷(DMA)。而当用300 μg·L~(-1)As(Ⅲ)处理时,P浓度降低至1/25P正，，螺旋藻胞内开始产生DMA,且DMA的含量随P浓度的降低(1/50P正)而增加。但是,As(Ⅴ)处理的螺旋藻甲基As比例较大(37.35%),而As(Ⅲ)处理的藻细胞内甲基As仅占5.58%。由此可以说明,当培养液中P浓度降低时,As(Ⅲ)处理下藻体胞内更容易产生甲基砷,但As(Ⅴ)处理下藻体甲基化能力更强。
[Abstract]:Spirulina is known as "the most ideal food in twenty-first Century". With the production and development of health care products, the safety quality of Spirulina has attracted more and more attention. In recent years, the content of arsenic (As) in Spirulina health-care products in some brands of our country is exceeding the standard, and the Research on the control of arsenic pollution in Spirulina is very urgent. The study is mostly focused on the determination of total As content in algae powder and the analysis of As pollution sources of Spirulina. The study of how phosphorus (P) concentration affects the adsorption of spirulina, absorption and transformation of arsenate As (V) and arsenite As (III) is still rarely reported. This experiment was studied with Spirulina platensis as an image, first with different concentrations of As (V) and As (III) to treat Spirulina 7 d, Study the adsorption and absorption properties of algal body on As; then reduce the concentration of P in the culture medium, study the effect of different P concentration on the growth of Spirulina; study the effects of different P concentration on As (V), As (III) adsorption, absorption and intracellular As form of Spirulina under the condition of algae growth. The main results are as follows: 1. different P concentrations to Spirulina The effects of P concentration (1/200P positive to P positive, P are P concentration in normal P supply 88.9mg. L~ (-1)) in the medium of normal P supply, and the effects of different P concentrations on the biomass of spirulina, algin and chlorophyll content were studied. The results showed that 1/10,1/25,1/50P was not a shadow of the growth of Spirulina. When the concentration of P was reduced, when the concentration of 1/100P was positive, the algal algin was significantly reduced and the content of chlorophyll increased; when P continued to decrease to 1/200P, the biomass of spirulina, the content of chlorophyllin and chlorophyll decreased, and the growth was significantly affected by.2. concentration As (V), As (III) was grown on Spirulina, and the effect of As enrichment was respectively As (V) (50,) 100150200250300 mu g. L~ (-1)), As (III) (50100200300 G. L~ (-1)) treated spirulina, compared the effects of different As treatments on the growth of Spirulina and the absorption properties of the spirulina. The results showed that the biomass of different concentration As (V) had almost no effect on the biomass of spirulina, and the biomass of As (III) treated by As (III) was compared with those without As treatment. There was an increasing trend, but the change was not significant. The As absorption, absorption and total arsenic content of Spirulina increased significantly with the increase of As concentration in the culture medium. At the same As treatment concentration, the As absorption and total arsenic content of the algae treated by As (III) were higher than that of As (V) treated algae, but the difference of As adsorption capacity was less.50100 micron G. L~ (-1). The treated Spirulina almost did not absorb As, and the As absorption of As (III) treated algae was 0.242,0.300 mg. Kg~ (-1). Therefore, the enrichment ability of Spirulina was stronger for As (III) at the same As concentration treatment. In addition, when the concentration of As (V) reached 150 mu G. The limited value of As in the healthy products was 1 mg. Kg~ (-1).As (-1).As (-1), 300 mu g L~ (-1), and the total arsenic content in the algae body was 1.471 mg. There are only As (V) As morphology in the cell of spirulina, while As (III) and As (V) exist in the cells of the algae treated by As (III), but the latter is adsorbed to Spirulina by the concentration of the main morphology.3., and the absorption and conversion of As (V), As (III) is set in the P concentration of the normal growth of the non sound spirulina. (300) (v.) L~ (-1)), As (200300) (III) (200300 mu g. L~ (-1)) treated spirulina, compared the difference between the concentration of P and the adsorption, absorption and As morphology of spirulina, As (III), absorption and intracellular As. The results showed that under normal P conditions, 300 micron G. The absorption of As in the algae increased to 1.369,2.181 mg kg~ (-1), and the As content absorbed by P decreased to 1.457,2.672 mg-kg~ (-1), indicating that the reduction of the concentration of P in the culture medium would promote the absorption of the algae and increase the risk of excessive pollution of Spirulina. The reduction also promoted the reduction, methylation and outer row of the intracellular As in Spirulina. When treated with As (III), spirulina had a strong oxidation effect on As (III) and reduced the concentration of P in the culture medium. Under the treatment of 300 mu g. L~ (-1) As (V), only when the concentration of P decreased to 1/50P, the two methyl in the cell of Spirulina was produced. Arsenic (DMA). And when the concentration of P is reduced to 1/25P with 300 g. L~ (-1) As (III), DMA is produced in the cell of spirulina, and the content of DMA increases with the decrease of P concentration (1/50P). When the concentration of P in the solution decreased, methyl arsenic was more likely to be produced in algal cells under As (III) treatment, but the methylation ability of algae was stronger under As (V) treatment.

【学位授予单位】：南京农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X173

【参考文献】