Extraction Technology Of Acid Protease From Octopus Viscera

With the requirement of marine products in today’s society, more and more marine lives were caught annually. There was a large number of aquatic waste,which was not only a waste of resources, but also polluted the environment.On the other hand,Native enzymes were widely needed, not only the enzymes extracted from terrestrial plants and animals, but also the enzymes from the marine resources,especially deep sea resources.In recent years, the researches about octopus viscera were focused on hydrolysing waste to obtain taurine, amino acid and functional polypeptide.There were few researches about the aspects of purifing acid protease.So in this paper, we tried to seek the best way to obtain the acid protease which in order to improve the utilization of by-products、turn waste into treasure、and provide reference for the following study.1.The content of crude protein is 16.0%,indicating that the octopus viscera could be used as the raw materials to extract protease and other nitrogenous substances.2.By the single factor experiment and response surface methodology, we obtained the optimum conditions were: pH5.0, temperature 30 ℃, time 2.5h, solid-liquid ratio of 1: 5. Under the optimal extraction conditions, the enzyme activity was 917.2nkat/g, and the specific activity was 17.4nkat /mg. Acidic protease mostly exsited in crude enzyme solution,76.0% of the total protease.3. The result ofacid protease’ preliminary separation showed that:(1)Salting: ammonium sulfate saturation of 80%, the maximum purification fold was 1.1, when the enzyme activity recovery was 76.0%, protein recovery was 69.0%.(2)The organic solvent assisted salting: 2% ethanol in the salting process, the maximum purification fold was 2.2, the enzyme activity recovery was 93.2%, protein recovery was 51.0%.(3)Membrane separation: purification fold was 6.4, activity recovery was 28.8%, 4.5% protein recovery.4.The result of ion exchange chromatography orthogonal experiments showed that:buffer pH was 7.0, sample volume was 10 mL, flow rate was 3 mL/min, the concentration of NaCl was 0.5mol/L, thus obtained product purification fold 16.5, at this time the activity enzyme recovery was 23.0%, protein recovery was 1.5%.5.Octopus acid protease preliminary application results shows that:(1)The sample of ion exchange chromatography,had reducing powe、hydroxyl clearance rate was 58.1%, superoxide anion radical scavenging rate was40.6%;(2)Enzymatic preparation mackerel skin collagen protein extraction rates was 29.5%.This article introduces the method of obtain acid protease from octopusviscera, it’s simple and convenient in utility. In addition, the reuses of leftovers promote high and new technology and in our country, and also has an important significance to the aquaculture industry.