Optimum Fermentation Conditions For Lignin Degrading Enzymes Of Bamboo Lignin Degradation Fungus

Bamboo fiber is a kind of new environmental friendly and cool-type fiber with capacious foreground. It has many values, such as, antibacterial, resistance to wear, water absorbability, and permeability. The resource of bamboo is abundant in China. If the bamboo fibril is exploited, it will have an important effect on textile domain. Biological degumming is a new developing way, it is very important to environment protection to decompose natural fiber. So biological is an advanced and green degummed method.In this paper, the writer systemically studied the optimum culture medium and conditions in shaking flasks by N1O23 and the degradation to bamboo fiber. The results are as followed:1) Regulation of nutrition:N1023 was inoculated in 5 different liquid state culture mediums. Enzyme activity of Lip, Mnp, Lac in each medium and the time of cultivation were compared so that the optimal original medium was decided:Glucose 20.0g/L, NH4Cl 3g/L MgSO4·7H2O 3 g/L, VB10.02g, bamboo lixivium 200 mL/L.In the base of the original fermentation medium, the optimum culture medium in shaking flasks for production by N1023 was studied. To measure three different enzyme activity in different culture medium and conditions through orthogonal experiment, the optimum culture components were:Glucose 18.0 g/L, bran 2 g/L, NH4Cl 3 g/L, Extract of wheat 4 g/L, MgSO4·7H2O 3 g/L, Tween-80 0.5 g/L, Veratric alcohol 0.001 g/L, CaCl2·2H2O 0.1 g/L, MnSO4 0.0375 g/L, VB1 0.02 g/L and bamboo lixivium 200mL/L. After culture medium optimization, Mnp activity of submerged fermentation liquid is 6.09 times as basic liquid medium; Lip activity of submerged fermentation liquid is 6.31 times as basic liquid medium Lac activity of submerged fermentation liquid is 5.96 times as basic liquid medium.2) The factors of Enzyme production:The biosynthesis of Lignin degradation was studied in various extents by six metallicions of Ca2+,Mg2+,Cu2+,Fe+,Mn+ and Zn2+. The effect of Mn2+ was the most to Mnp. But, the existence of Mn2+ has inhibitted the enzyme activity of Lip and Lac. Ca2+, Mg2+ and Fe3+ are advantageous to the Lip expression; Ca2+ and Cu2+ are helpful to the production of Lac.Twain-20, Twain-80, deoxycholic acid sodium and Triton X-100 of four kinds of surfactants was studied.The results showed that, all of those can increased the enzyme activity, and the influences of Twain-80 was the most to three enzyme.The induction of five inducers:veratryl alcohol, nicotinic acid, phenol,a-na phthaleneacetic acid and 1‰Kraft Lignin was studied.The results indicated that, all of them can increased the enzyme activity, and the effect of Mn2+ was the most to three enzyme.In the base of the the optimum culture medium, the optimum fermentation conditions were studied. The optimum conditions were:the initial pH of medium 5.5, 75ml medium in 250 ml shake flask, the inoculation amount is 10%, culture time 5x24 hr. the temperature is 32℃, the shaking speed is 140r/min. Mnp activity of submerged fermentation liquid improved remarkably in the optimum culture and conditions, with 1.75 times as non-optimized culture conditions and 49.26 times as basic liquid medium; Lip activity of submerged fermentation liquid improved remarkably in the optimum culture and conditions, with 1.53 times as non-optimized culture conditions and 9.62 times as basic liquid medium; Lac activity of submerged fermentation liquid improved remarkably in the optimum culture and conditions, with 1.77 times as non-optimized culture conditions and 7.04 times as basic liquid medium.3) The microbe degumming of bamboo fabrics:Used N1023 in microbe degumming of bamboo fabrics, the degradation rate of lignin is 48.96%, and the degradation rate of holocellulose is 26.03% after 30 days and the selectivity coefficient of lignin degradation was 1.88. Bamboo fabrics samples of non-treated, different culture medium treated were analyzed with infrared spectrum. According to the related peak variety of lignin and hemicelluloses, N1023 was able to highly offer a selective degradation on lignin and hemicellulose on the optimum culture medium.