Selecting Of High Pectinase Activity Strains And The Study On The Enzyme Character

The pectinase is the total call of the things that can break up the pectin.It's category usually conclude the PG,PE and PL.Traditionally the pectinase is used to the processing of the syrup and the ratafee.Now the application extend to the fields including the extract of the vegetable juice,antisepsis of the wood, ethanol fermentation, feedstuff,colloid remove of the hemp,refining and processing of the cotton weave.In our country the solid fermentation is common.Beacause this method is extensive and it's product is hard to reach the request of some industries especially the food industry,the pectinase is limited greatly to apply in the industry producing.Now the researches in our country is most about the sigle pectinase and the complex study on the PG,PE and PL in the process of the fermentation is less.The study is based on a excellence strain-Asperillus niger SS9 and get the optimum condition of the pectinase producing through the enzyme activity analyse of the three pectinase.We can find the distance between our production and the oversea's through the enzyme activity contrast.The experiment is started with Asperillus niger and Rhizopus strains selecting which is conserved in the lab.For the variety of the selecting methods the experiment choosed three different mediums,and through the contrast a effective path has been concerned .A strain which has the great ability to break up the pectin come true.On the study we can confirm that the 3th selecting medium is useful and effective.To learn the live character and offer the reference to the next experiment,we meature the strain's growth speed.We have got twelve strains which has the activity from ten soil swatches.The result is the confirmation od the selecting method we desired and this will be a effective and dependable way for the pectinase strain selecting.Through a series of researchs some factors which can influence the pectinase production have been researched and comfirmed. We made the cultrue optimized and the result studying is indicated: in initial pH5-7,temperature 28℃-30℃,the best sonstitue of the culture is citrus peel powder 3 g, bran 12 g , urea 0.075 g, (NH4)2SO4 2 g,CaCl2 0.03 g, KH2PO4 3.8 g, K2HPO4·3H2O 0.2 g,glycol 15 mL, H2O 100 mL , pH 6.0, Output is : PG 32,820,000 U/ mL, PE 31862 U/ mL, PL 0.716 U/ mL.In the process we study the culture optimization of the PL especially.Based on the complex nitrogen researchs we made the culture that can produce PL conformably: citrus peel powder 4g, bran 20 g , urea 0.075 g, NaNO3 0.4 g,CaCl2 0.03 g, MgSO4 0.05 g,KH2PO4 3.8 g, K2HPO4·3H2O 0.2 g,glycol 15 mL, H2O 100 mL , pH 6.0,the PL can reach 1.267 U/ mL.And we made the ferment curve of the three enzymes.Through the research on the character of the different pectinase,we learned that the optimal pH(PG 4.0,PE 6.0,PL 6.0); the pH stability of the three pectinase(PG 2.0～8.0,PE 4.0～7.0,PL 5.0～8.0);the optimal temperatur(ePG 50℃,PE 50℃,PL 45℃); the temperature stability of pectinase(PG below 55℃,PE and PL below 50℃).The pectinase liguid of the fermentation is applied to the research that improve the rate of the apple juice lixiviated.Through a series of the optimization a fit condition for the experiment is that:the initial pH is 3.5,the temperature is 40℃,the quantity of the pectinase used is 0.5 percent,the time of the reaction is ninty minutes,the rate of the juice lixiviated is the highest.We can find the difference between the pectinase we produced and the enzyme product overseas through the contrast of the component analysed.Through the research we can discover that the activity of our production is lower and the juice rate is also lower.The result is not only the PG but also the PL is important to the apple juice.The factors influence the juice lixiviated can also be analysed and this research will be useful for the next study.