产黄纤维单胞菌CR-14菌株诱变选育及发酵条件优化

为提高产黄纤维单胞菌CR-14纤维素酶活力,对菌株进行亚硝酸、紫外线及复合诱变处理,筛选产纤维素酶活较高的突变株,并对其发酵条件进行优化。结果表明,经亚硝酸和紫外线复合诱变得到一株产纤维素酶活较高的菌株Y-UA-18,其酶活力为10.57 U,为原菌株产酶活力的1.67倍。通过正交试验得到菌株Y-UA-18产酶最佳培养基为:秸秆粉1.0%、复合氮源0.6%、KH2PO40.1%、Mg SO40.1%、Na Cl 0.08%;最佳培养条件为:初始p H值7.0、培养温度30℃、发酵时间3 d。通气量对菌株Y-UA-18产酶影响不明显,但在厌氧条件下发酵液酶活显著降低,0.1%TW-80对菌株Y-UA-18的产酶没有影响。

Screening and Mutation Breeding of the Celloulonmonas flavigena CR - 14 and Optimization of Its Fermentation Conditions

The Celloulonmonas flavigena CR-14 was screened from the rumen of cattle, which had the ability of producting cellulose and was stored in our laboratory. In order to improve the cellulose activity of the CR-14, it was treated with nitrite, ultraviolet(UV)and complex mutagenesis. Initial selection identified 6 cellulase-producing strains, as demonstrated by their ability to turn Congo red plates yellow. These 6 strains were then rescreened by determining the cellulase activity of broth. Finally, through nitrite and UV mutagenesis,Y-UA-18 strain with the high cellulose yield and stable characteristics, which enzymatic activity was 10.57 U, 1.67 times of starting strain CR-14, was screened out. In order to provide a theoretical reference to the industrial production of the strain Y-UA-18, we conducted the single factor test and orthogonal test to the fermentation medium components and the fermentation conditions. The results showed that the best medium of strain Y-UA-18 enzyme production was as followed:straw powder 1.0%, nitrogen source 0.6%, MgSO40.1%, KH2PO40.1%, NaCl 0.08%. The optimum fermentation conditions were:initial pH 7.0, incubation temperature 30℃, fermentation time 3 d, the effect of ventilation for strain Y-UA-18 enzyme production was not obvious, but under the condition of anaerobic, the enzyme activity of fermentation liquor was reduced, 0.1%TW-80 had no effect for enzyme production.