Optimize The Cultivation Of Rhodococcus And Modify Acrylic Fibers With Its Rude Enzymatic Liquid

Acrylic fiber is one of thermoplastic synthetic fibers. It has many desirable properties such as high intensity, high elasticity, good hue, and so on. It is similar even prior to wool in many properties. However, it also has some undesirable properties. That is, it has low hydrophilicity and higher static effect. Traditional physical modification on acrylic fibers can't keep its good properties, while the chemical modification needs harsh reaction condition and will bring environmental pollution. As the enhancement in study of enzyme, the investigation and application of enzyme has penetrated into many areas. It is studied here that the enzymatic modification in acrylic fibers.In acrylic fibers, the acrylonitrile units link head to tail mainly. This structure induces the nearby -CN in the same polymer repulsing as a result of their same polar direction, and the nearby -CN between the neighborhood polymers fetching each as a result of their opposite polar direction. So, the polymers present as irregular helix clubbed conformation. And it is also laterally ordered. Acrylic fibers' conformation determines the low hydrophilicity. Nitrile invertases are the enzymes which can transform -CN into -CONH₂ or -COOH. So here a research is studied that destroy the high polar -CN using nitrile invertase in order to increase the fibers' hydrophilicity. In this paper, the Rhodococcus was selected as a working strain which can produce nitrile invertase (nitrilase, nitrile hydratase, amidase included) and the rude enzyme was extracted from it. Then, the liquid was used to modify acrylic fibers in order to get well hydrophilic and anti-static properties. The assessments include moisture regain, electrostatic half life time, dye uptake of ionic dye and the K/S of acid dye. Nitrile invertases exist inside the bacilli of Rhodococcus, and it is revulsive enzymes. The enzymatic activity was affected from many factors. Therefore, we firstly searched after a good growth condition for nitrile invertase production and activity by means of assaying the nitrile invertase activity through GC. This is the first part work of the research. It was found that it is good for the growth of the bacilli and the increase of the enzymatic activity when pH=7, initial glucose concentration 15g/L, at the temperature of 30℃for 72 hours. Some metal ionic could enhance the enzymatic activity to some extent, especiallyCoCl₂ at the concentration of 15mg/L. Revulsants such as caprolactam, Urea, Acetamide, and Cyanide could improve the production of bacilli and the enzymatic activity. When Urea used 0.6%, the highest enzymatic activity was got for 168.4U/mL.The second part of the research is to find the best condition for enzyme reaction and modify the acrylic fibers with extracted enzymatic liquid through bacilli broken up. It was found that when the medium pH=7, at the temperature of 40℃the reaction occurred rapidly. The best condition for ultrasonic fragmentation is working for 12.5 minutes at the power of 240W.After modification of the rude enzymatic liquid from Rhodococcus, the fabrics' moisture regain, electrostatic half life time, the dye uptake of the ionic dye and the K/S of the acid dye performance better. Therefore, a further research was carried. The additives such as surfactants or small molecular of organic solvents is added into the rude enzymatic liquid. When 5%iso-propanol and 0.5% Non-ionic Penetrating Agent MP were added into the enzymatic liquid, the fabric after modified for 24 hours exhibit good results. The K/S value increased more than 5 times, and the electrostatic half life time declined to 2.39s. The other two parameters improved largely, as well. By the means of XPS test of the acrylic fibers, some of the -CN were found to be converted into -COOH and -CONH₂.The research of the enzymatic modification in acrylic fibers has got some results. The fabrics' moisture regain, electrostatic half life time and the dyeability improved obviously.