Agar Extraction And The Purification Of R-phycoerythrin From Pyropia Haitanensis And Gracilaria Tenuistipitata,and The Subsequent Wastewater Treatement

The resources of red seaweeds are abundant and distribute widely.China is the country with the largest amounts of red seaweeds in the whole world.Many researches focus on the resources of red algae,aquaculture and its uses increasingly.But making full use of red algae about the extraction of natural products is still a key problem.Pyropia haitanensis and Gracilaria tenuistipitata are the large-scale economic seaweeds that widely cultivated along the Chinese coastal areas.The two kinds of algae are not only rich in phycobiliproteins,but also other nature products with high value such as agar.In this paper,in order to make full use of Pyropia haitanensis and Gracilaria tenuistipitata,save resources and reduce the wastewater,R-phycoerythrin and agar with high additional value are extracted from the two kinds of algae successfully.In addition,the wastewater from the whole extraction are treated by green tide of Ulva prolifera.And the conditions of the treatment process were optimized to determine the optimal dilution multiple,the best treatment days and the best material-liquid ratio.This environmentally-friendly biological treatment method can remove nutrients effectively.It can save the cost of wastewater treatment and protect the environment.The main conclusions are as following:1.Firstly,the R-phycoerythrin was extracted,isolated and purified from the two algae successfully.0.74g/mg and 81.1?g/g of food-grade R-phycoerythrin were gained from 100.00 g of Py.haitanensis and 1000.00 g of G.tenuistipitata respectively by expended bed chromatography.The quanlity and recovery of R-phycoerythrin was0.24g/mg and 12.12%with the purity above 4 from Py.haitanensis by ion exchange column chromatography.While the quanlity and recovery was 45.30?g/g and 20.70%with the purity above 4 from G.tenuistipitata.And the R-phycoerythrin was then identified by SDS-PAGE,Native-PAGE and absorption spectrum.Thus,the high-value product of R-phycoerythrin was gained for large scale from these algae.2.Secondly,the agars were extracted from the residues after the purification of R-phycoerythrin from the two species of algae.The agar yields of G.tenuistipitata and Py.haitanensis were 21.32±1.95%and 5.82±0.17%respectively.The agar from Py.haitanensis was with a gel strength of 796.00±28.10 g/cm²,a gelling temperature of38.10±0.22?C,a melting temperature of 89.50±0.55?C,3,6-anhydrogalactose content of 34.00%±3.16%,and sulfate content of 3.01%±0.24%.And those data from G.tenuistipitata was 789.60±34.77%,36.20±0.27%,91.00%,4.93±0.26 and 34.07±1.96%respectively.There were no significant differences between these parameters and those from the direct extraction of the two species of the algae.And the couple of physico-chemical properties were shown that the agars from these two kinds of seaweeds had the industrial applications for large-scale.In addition,the method of extraction could reduce lots of water,amount of sodium hydroxide,decrease the production of wastewater.The water consumption of the comprehensive extraction from 100.00g of Py.haitanensis or 1000.00g of G.tenuistipitata were 75.40 L or 17.40L less than the control.The consumption of alkali were 0.80L or 0.40 L less than the control.And the whole waste liquid output were 78.31L and 21.50L L less than the control.So,the method was benefit to the agar industries.Meanwhile,the four kinds of agar from two different algae could also be used as a material for DNA electrophoresis or a bacterial culture medium,and the commercial agarose or agar were as control.Based on the results of DNA electrophoresis,the bands were separated clearly through the four kinds of agars which we extracted from G.tenuistipitata and P.haitanensis.The two kinds of agars were also used as a material for culturing the bacterial,the amounts of bacterial colonies were 78.20±8.76%and 79.40±11.33%from G.tenuistipitata.And the amount of bacterial colonies were 72.30±5.21%and70.50±6.84%from aging Py.haitanensis.The result indicated that the four types of agars from Py.haitanensis and G.tenuistipitata did not appear to show a general inhibitory effect on bacteria growth.Thus,the agar we extracted could also be applied as the common study without purification.3.The condition of culturing the U.prolifera for treatment of wastwater from the whole process of extraction were optimized.The wastewater from the whole extraction process of Py.haitanensis or G.tenuistipitata need be diluted two times or four times.The different days were set as 1-7 days and the different material-to-liquid ratio were set as 3.7g:1L?7.4 g:1 L?14.8 g:1 L and 29.6 g:1 L respectively.The optimum time of culturing the U.prolifera for treatment of wastewater from the extraction of agar either from Py.haitanensis or G.tenuistipitata were all 48h under material-to-liquid ratio of 7.4 g:1 L.The growth rate of U.prolifera were 8.33±0.31%or 6.63±0.64%respectively.The results showed that the removal rates of BOD₅,COD,total nitrogen,inorganic nitrogen,ammonia nitrogen,nitrate,nitrite,total phosphorus and inorganic phosphorus were 53.29±0.85%,49.16±0.31%,42.50±6.70%,66.53±0.78%,48.59±1.26%,73.47±1.57%,73.59±1.33%,69.30±4.09%and 77.69±4.54%after the treatment of the wastewater from the whole extraction of Py.haitanensi for 48 hours under the material-to-liquid ratio of 7.4 g:1L.And those indicators from G.tenuistipitata were 50.27±1.52%?34.02±3.36%?41.34±4.16%?67.30±2.43%?48.53±3.20%?74.11±7.11%?76.50±2.35%?63.71±2.54%and 76.30±0.30%respectively.Thus,U.prolifera could remove N and P from the wastewater effectively.It greatly reduced the pressure on the environment caused by the effluent discharge,and provides new ideas for the wastewater treatment of related industries.In summary,this paper establishes a comprehensive extraction technology through the inferior Py.haitanensis and G.tenuistipitata.And it lays a foundation for the full utilization of biomass.At the same time,this paper was also focused on the treatment of the wastewater from comprehensive extraction.The cheaper and simpler operation of biological treatment ws carried out by U.prolifera.It not only achieved the purpose of utilizing U.prolifera during the green tide period,but also solves the problems of wastewater treatment in the production of agar.It provided a metod of sustainable development for industries from the economic red alga that conformed to the transformation of new and old kinetic energy in China.