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Kojic acid (Kojic acid), chemical name 5 - hydroxy-2 - (hydroxymethyl) -1,4 - pyrone is secondary compounds produced by fungi aerobic fermentation of a weak acid having a tyrosinase ability, antibacterial ability oxidase inhibition and chelation of metal ions can be used as a skin lightening agent, food preservatives and preservative, analgesics, pesticides, spices used in food, cosmetics, medicine, agriculture and other related fields are a great value. In addition, kojic acid can also be used as a spice synthetic and biodegradable plastic synthetic intermediates. Kojic acid fermentation production at home and abroad kojic acid fermentation production technology is still not mature enough, kojic acid in short supply on the market, expensive, and therefore must be vigorously. As material Bingtang hesperidin Filter from moldy Bingtang hesperidin excellent kojic acid producing bacteria, through different physical methods it stepwise mutagenesis, kojic acid fermentation technology has been studied, and finally on kojic acid extraction method has been systematically studied, the main findings are as follows: from the moldy rock sugar, orange peel by screening a good traits kojic acid producing bacteria, kojic acid production reached 15.68g / L, by comparison the colony characteristics and microscopic characteristics of the strains identified this strain of Aspergillus oryzae this study, the number of Aspergillus oryzae A-55. 2. Aspergillus oryzae A-55 as a starting strain, UV, microwave and 60Co three mutagenesis: 20W UV lamp the 20 mmin conditions from 30 cm irradiation under UV-78 mutant strain of Aspergillus oryzae, kojic acid was 37.8g / L, a 141.1% increase compared to the original strain;, Aspergillus oryzae mutant UV its microwave mutagenesis -78 as the original strain, studious rate of 800 W, a pulse frequency of 2450 Hz in the microwave, the microwave total processing time for 6 min screening mutant strain of Aspergillus oryzae M-33, kojic acid was 59.7 g / L, compared with the original strain kojic acid yield increased by 57.9%; Third, as the original strain of Aspergillus oryzae mutant M-33, its 60Co-Y radiation mutagenesis, the best radiation mutagenesis a dose of 800 Gy in screened this condition - excellent Aspergillus oryzae mutants Co-26, kojic acid was 70.1g / L, compared with the original strain rate of 17.4%. Aspergillus oryzae mutant Co-26 in the initial fermentation medium by adding a certain concentration gradient of the ethanol as a kojic acid production promoting agent, the results showed that the mass concentration of 6% ethanol Preferably, kojic yield increased by 16% based on the original. On this basis, through single factor test to determine the optimal carbon and nitrogen sources were soluble starch and peptone; Plackett-Burman experimental design, screened kojic acid production factors significantly affect: soluble starch, peptone and initial pH. This three most are climbing test to determine significant factor test value level of response surface, followed by Box-Behnken experimental design and regression analysis, the best medium for final: the soluble starch 8.3g / L, peptone 5.0 g / L, MgSO4 · 7H2O 0.5 g / L, KH2PO4 1.0 g / L, KCl0.5g / L, FeSO40.01 g / L, the initial pH 6.1, kojic acid production reached the maximum 99.89g/L4. impact decolorization effect of four single factor test, and ultimately determine the best dosage of activated carbon for decolorization pH 3.5, decolorization temperature of 80 ° C and bleaching time of 40 min, the decolorization rate of 77.68%, 98.78% of the song acid yield. Further, better by using a cation exchange resin to remove impurity cations in the solution of crude kojic, taken directly to the concentration crystallization method of directly obtained kojic crystallization, the finally obtained kojic crystals with a yield of 78.67%, the products The purity of 98.26%.
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