Studies Of Seaweed Extract Made From Laminaria Japonica

Laminaria japonica,a type of seaweed,is extensively cultivated in China.In this paper,it was used to prepare seaweed extract by physical,enzymatic and fermentation technologies.The fertilizer made from the seaweed is abundant with oligosaccharide,biological active substances and mineral elements.The aims were to study the effects of the seaweed extract on the germination of mung bean and maize seeds,and to analyze the biological active substance.The main results were showed as follows:1.The optimum parameters for the enzymatic hydrolysis of L.japonica by alginate lyase were:enzymatic dosage of 72 U,the substrate concentration?W/V?of 1:100,temperature of 30?,pH of 8.5,and the reaction time of 8 h.The optimum conditions for the ultrasonic wave assisted extraction were:the power of ultrasonic wave of 447.97 W,operating time of 16.0 min.The effects of the seaweed extract made by the enzymatic hydrolysis method assisted with ultrasonic wave on the germination of mung bean and maize seed were studied.The results showed that it was best suitable for the germination of mung bean seedwhen the seaweed extract content was 20%.In the 3th day,as compared with the control samples without seaweed extract,the length of hypocotyls,the length of epicotyls,the activity of a-amylase and the content of soluble reducing sugar of the mung bean seeds with 20%seaweed extract were improved by 5.79%,44.07%,16.35%and 13.36%,respectively,and the MDA content was decreased by 12.44%.Moreover,the results found that 30%seaweed extract was best suitable for the germination of maize seeds.In the 5th day,as compared with the control samples,the length of hypocotyls,the length of epicotyls,root-shoot ratio,the activity of a-amylase,the content of soluble reducing sugar of maize seeds treated with 30%seaweed extract were improved by 43.15%,19.21%,46.72%,64.80%and 13.36%respectively,the content of MDA was decreased by 9.71%.2.The optimum parameters of Acinetobacter junii X8 fermented L.japonica were studied.The results showed that the optimum fermentation medium composition?w/v?and culture conditions were as follows:NH₄Cl of 0.25%,K₂HP04·7H20 of 0.1%,MgSO₄ of 0.1%,initial pH value of 7.5,rotation speed of 150 rpm.Furthermore,the effect of fermentation period on germination of mung bean and maize seeds was analyzed,the results showed that the optimum fermentation period was 5 days.3.The effects of seaweed extract on the germination of seeds were studied.The result showed that seaweed extract with the concentration of 12%could enhance the germination of mung bean seed.In the 3th day,the length of hypocotyls,the length of epicotyls,the activity of a-amylase and the content of soluble reducing sugar of mung bean seed treated with 20%seaweed extract were improved by 41.94%,30.85%,33.07%and 6.91%,respectively,as compared with the control samples.Moreover,the result found that 16%seaweed extract could enhance the germination of maize seeds.In the 5th day,the length of hypocotyls,the length of epicotyls,root-shoot ratio,the activity of ?-amylase,the content of soluble reducing sugar of maize seeds with the seaweed extract were improved by 36.10%,30.01%,24.09%,32.24%and 20.37%,respectively,as compared with the control samples.The results showed that the content of MDA of mung bean and maize seed wasn't decreased in this experiment.4.The analysis of LC-MC for seaweed extract showed that the alginate-derived oligosaccharide mainly has 3 aldehyde-acid untis.The results suggest that oligosaccharide probably enhanced germination.