Production Of Mannase And Application For Degumming Of Ramie

Ramie is a plant of excellent raw material for textile fibers. At present, the enzymatic degumming of ramie are the research focus in textile industry, which by using the extracellular enzyme from the latter period of microbial fermentation directly or by enzyme degradation of glial ramie to release the ramie fiber. Compared to the traditional chemical degumming, the enzymatic degumming method can improve the quality of pure and dry ramie, reduce environmental pollution dramatically, enhance economic and environmental benefits significantly, and owns a great prospects for future development. The research includes two parts:The first part of the experiment has done the test in enzymatic properties and fermentation conditions of the Mannanase genetically engineered Pichia pastoris strain which preserved in our laboratory. The results showed that the recombinant enzyme optimum pH is 5.5, the optimum reaction temperature is 50℃. However, because of the weak ability of enzyme heat resistance, there left 70% of residual activity after heat preservation at 60℃during 10 min, and almost lost the enzymatic activity when temperature exceeds 80℃. When we use 50 L fermentor and methanol induction in fermentation, we can achieve a result of 4204 U / mL recombinant mannanase activity after 96h, which provides basis for the industrial scale production and makes the foundation for the enzymatic biological degumming of ramie.The second part of the experiment is to find the optimum technical conditions of the degumming of ramie by united function of xylanase, mannanase and pectase. These include liquor ratio, bath time, bath temperature, preconditioning methods, and three respective enzymatic concentration and optimal reaction pH of xylanase, pectinase and mannanase. The final optimized conditions were as follows: first,put the RAMIE in 0.001 mol / L of HC1 boiling 30 min for pretreatment, and then soak into the complex solution of the three enzyms. Degumming conditions are pH 5.0, temperature 50℃, bath ratio 1:36 and time 12 h, in which, xylanase activity was 800 U / mL, pectinase activity was 600 U / mL, mannanase activity was 800 U / mL, and the rate of residue after degumming was 7.38%. There is still certain distance from the textile standards, and thus demands some auxiliary means in order to meet the requirements.