Isolation Of Fucoxanthin From Laminaria Japonica, A High-Quality Raw Material To Produce Seaweed Fertilizer

Laminaria japonica is containing considerable fucoxanthin, which accounting for more than 60% of the total carotenoids in Laminaria japonica. It has the function to prevent and cure cancer, accelerate decomposition of fat and lower fat and cholesterol. In addition, Laminaria japonica is a high-quality raw material to produce seaweed fertilizer, and it is treated with alkali to extract the plant growth regulators. But the treatment make fucoxanthin which have great economic benefits and many biological activities destroyed and discarded, and generates a great waste of resources. We extract fucoxanthin from laminaria japonica with acetone firstly, and then residue is made into seaweed fertilizer by alkali digestion. The method provide experimental evidence for improve utilization and additional value of raw material in industrial production of seaweed fertilizer. According to the single factor experiment and the orthogonal experiment, we determine the best extracting conditions: Laminaria japonica is pretreated with 4 mL/g distilled water, then soaked it with 5 mL/g acetone at room temperature, acetone/ Laminaria japonica =5:1 (mL/g), extract twice, once 30 min, and recovery rate of fucoxanthin is 72.4%.The separation of fucoxanthin was carried out by the method: 1/2 volume of hexane is added to the acetone extracts for transferring and preparatory separation of fucoxanthin. The purification of fucoxanthin is carried out by silica gel column chromatography twice with acetone:hexane=1:3 and acetone:chloroform=1:9 as eluent, and high-purity fucoxanthin were obtained.The further purification of fucoxanthin is carried out by preparative high performance liquid chromatography (19×300 mm, 7μm, SymmetryPrepTM; methanol:water=89:11; 8 mL/min; 8 mL) and preparative thin layer chromatography(chloroform:acetone=6:1), and purity of fucoxanthin over 99% and 95%. The pigment is identified by the methods of UV absorption spectra, NMR and MS, and its spectral data is identical with those reported.Laminaria japonica have been extracted with acetone is added in twice volume of water and 5% of total volume (the volume of seaweed residues and water) of KOH, and digested for 2 h at 80 oC, then centrifugation was used to remove insoluble substances and collect liquid as seaweed fertilizer. In field experiment, the seaweed fertilizer increase yield of Chinese Cabbage by 41.98% and show good effect to promote growth of crop. In this study, we extracted fucoxanthin from Laminaria japonica with acetone before it is made into seaweed fertilizer by alkali digestion. The method of fucoxanthin extraction is time-saving, efficient and the solvents used are recovered easily. Besides, the seaweed fertilizer produced by this method still has good effect to promote growth of crop. Therefore, the study provide experimental evidence to improve utilization of raw material for industrial production of seaweed fertilizer.