Studies On Culture And Co-production Extraction Of Lipid And Paramylon Of Euglena

Euglena,a single-celled freshwater algae,which can produce a variety of active substances such as polyunsaturated fatty acids and paramylon,and which has been widely used in food,pharmaceutical,feed and other fields.In this study,Euglena gracilis FACHB-848 was selected as the research object to screen the suitable medium for the growth of the algae and the synthesis of active substances.Then,the growth of Euglena gracilis were evaluated using the types and concentrations of carbon and nitrogen sources.Finally,the green integrated technology was developed to co-produce oil and paramylon from Euglena,providing a practical basis for industrial development of Euglena.The main research results are as follows:First,to study the growth of Euglena in the media of AF-6,BG11,C,CM,Hutner and Hut,the results showed that Euglena was suitable for cultivation in CM medium.The biomass of Euglena gracilis cultured in CM medium was much higher than that of the other five media,and the biomass was 1.22 g/L.Biochemical composition of Euglena cultured in CM medium was as follows: The contents of protein,lipid and paramylon were 48.21%,33.33% and 10.43%,and the corresponding yields were 0.54 g/L,0.38 g/L and 0.12 g/L,respectively.The contents of total chlorophyll and carotenoid were 60.00 mg/g and 9.50mg/g,and their yields were 65.48 mg/L and 10.39 mg/L,respectively.Second,the effects of carbon and nitrogen source changes on the growth of Euglena were studied.It was found that the lower concentration of nitrogen source(0.0625 g/L urea)could meet the growth demand of Euglena,and the biomass could reach 1.23 g/L.High nitrogen concentration(1 g/L)may restrict the growth of Euglena.Glucose is the best carbon source for Euglena.The biomass of Euglena cultured at 8 g/L glucose can reach1.94 g/L,and the content of paramylon is 22.79%.2 g/L glucose can significantly increase lipid content of Euglena,which is 50.40%.After 8 days of 16 g/L glucose culture,the biomass concentration decreased,and the final biomass was 1.32 g/L.Excessively high glucose concentration was not conducive to the growth of Euglena.Third,to study the technology of co-production of lipid and paramylon from Euglena and optimize the technological parameters of co-production of lipid and paramylon from Euglena.In terms of lipid extraction from Euglena,n-hexane and ethanol were selected as the extraction media to optimize the oil extraction process.The optimal oil extraction conditions were as follows: the volume ratio of n-hexane to ethanol was 1:1,and the solidliquid ratio was 1:80.The oil was extracted at 25? for 1 h,and repeated for 3 times.The effects of enzyme treatment on the extraction rate of paramylon were studied by using Euglena residue after oil extraction.The optimum extraction conditions of paramylon were as follows: The trypsin activity was 7500 U/g algal powder,the ratio of material to liquid was 1:80,and the enzymatic hydrolysis time was 6 h.Two kinds of algae resources,namely lipid and paramylon,were extracted innovatively by this process.The oil extraction efficiency reached 96%.The content of paramylon was higher than that of traditional methods(SDS+Na2EDTA method and biological enzyme method).The results indicated that the oil extraction process did not affect the performance of protease extraction process for paramylon.In addition,compared with the traditional methods,the co-production of Euglena lipids and the paramylon extraction technology required less time to extract the paramylon substances.Therefore,the co-production extraction of lipid and paramylon from Euglena is a new green and efficient extraction technology,which can comprehensively utilize euglesia biomass,provide a practical basis for the intensive development of microalgae biomass,and promote the development of microalgae industry.