Microorganisms Continuous Straw-Degradation And The Separation And Purification Of Polysaccharide Product

Straw is amounts of biological resources, which has important practical value b y fermentation polysaccharide product. Based on the corn straw as the research material, this study can be divided into three parts: First of all, to find the microbial growth late logarithmic phase, analyzing the relations between polysaccharide production and microbial growth, so as to determine the continuous culture feeding time. on the basis of previous work, purifying polysaccharide product. The next, Designing a suitable fermentor for the straw suspension. Eventually, using this device to continue fermentation to optimize of corn stalk fermentation test conditions and get best microorganism fermentation condition, extend the microbial growth period, then people will obtain the maximization of polysaccharide accumulation. Three parts conclusion as follows:(1) To optimize the Activation of medium : Activation medium which adding sodium CMC-Na and yeast extract maybe have an affect on the production. Further experiment shown that yeast extract did not impact on product composition. To reduce background value, the study used straw powder instead of sodium CMC-Na.(2) Choose the method of Polysaccharide purification: Compared with methods of TCA, and HCl, The polysaccharide loss rate(17.9%) by the way of Sevag was relatively low, the removal rate of protein(80.11%) was slightly lower than HCl method(89.67%), as a result, Sevag method was more suitable for purifying the straw-fermented production of polysaccharides.(3) Refine polysaccharides: Using column chromatography purify crude polysaccharide FFSP, two polysaccharide samples named FFSP1 and FFSP2 were collected, but there were still a litter protein in FFSP1 and FFSP2, so as to infer that polysaccharides could be a glycoprotein.(4) Determinate Bacteria growth curve: The primary metabolites polysaccharide produce In bacteria adjustment period, logarithmic phase and stable period. The growth of bacterial enter into the stable period after 48 hours. Polysaccharide production reache d the maximum value in this period, and could be stable for some time, it shown that we could through the extension of the flora of stabilization to maximize accumulation of products.(5) Design Fermentor: Fermentor selected 316 L stainless steel, the total volume of tank is 5 L, the internal diameter is 147 mm, wall thickness is 3 mm, liquid loading coefficient is 70%, work pressure is 0.1 MPa, flange cover is 240 mm diameter, jacketed Canon is 10 mm.(6) Designed a device which used to continuous straw fermentation: setting the Pipe diameter of in and out mouth as four points, by connecting pipe diameter converter to change the pipe diameter, control the flow, and measure precision, the device not only adapt to li quid fermentation culture medium, but also can be used for solid suspension fermentation.(7) Designed a inlet device which used to continuous straw fermentation: solved the problem of dye bacterium and it is difficult to clean up after solid material blocking the jet hole. it mainly including air pump, silicone hose, pneumatic diaphragm valve, gas meter, the common air filters, precision air filters, fermentation tank inlet pipe and circular air distributor. silicone-hose connect those device in turn. The inlet pipe Fixed in the flange cover, with the end have a thread structure, thread length is 5 cm, then the height of the air distributor can be adjusted up and down. At the end of the Inlet pipe and distributor set conical external thread, those structure combine with the rebar joint connection have one thread structure at each end. The distributor set in 1/3 height of tank.(8) To optimize the fermentation conditions: Through PB designed continuous fermentation experiment, the results shown that the dilution rate was significant negative impact. The single factor experiments of dilution rate found out in the dilution rate of 0.353 m L/min, the accumulation of polysaccharide product of continuous fermentation was stable, and compared with the other different dilution rate this condition could acquire the highest yield of polysaccharide.This experiment promoted industrialization of straw fermentation,and laid a good theoretical basis for the straw resource utilization.