Controllable Degrading Poly (3-hydroxybutyrate) To Monomer And Studies On The Condition Of Fermentation

Three fungus have been obtained from fourteen strains preserved in the laboratory by paper chromatography, respectively is Penicillium sp.DS9701-02, Penicillium sp.DS9707 and Penicillium sp. DS9713a-01. They can degrade PHB granules and the end product is the monomer.The culture medium were harvested by centrifugation at 12000×g and 4℃for 30 min and separated by ultra filtration, then they were directly analyzed by high-performance liquid chromatography.The culture medium were analyzed by high-performance liquid chromatography (HPLC) with a Shim-pack Vp-ODS C18 column(150L*4.6). The separation was carried out by elution start with H2O (adjusted at pH 2.8 with HCl)-acetonitrile (85:15,v/v) at a flow rate of 1 ml min-1.The wavelength for detecting eluates was 210 nm, the temperature is10℃.According to the result of single factor test, an orthogonal experiment (four factors and three levels) was designed; the studied factors are concentration of carbon, nitrogen, phosphorus source, and initial pH of culture medium. The optimum condition is as follows:1. The Penicillium sp. DS9701-02: The optimum fermentation time of Penicillium sp. DS9701-02 is 7 days. The optimum condition is: carbon source is 0.75g/L, nitrogen source is 0.5g/L, phosphorus source is 11.94/4.54g/L, and initial pH of culture medium is 5.5.2. The Penicillium sp. DS9707: The optimum fermentation time of Penicillium sp. DS9707 is 7 days. The optimum condition is: carbon source is 0.75g/L, nitrogen source is 2g/L, phosphorus source is 5.97/2.27g/L, and initial pH of culture medium is 5.5.3. The Penicillium sp. DS9713a-01: The optimum fermentation time of Penicillium sp. DS9713a-01 is 8 days. The optimum condition is: carbon source is 0.75g/L, nitrogen source is 1g/L, phosphorus source is 5.97/2.27g/L, and initial pH of culture medium is 5.5.