养猪发酵床中净水芽孢杆菌的分离及其固体发酵研究

SEPARATION AND ITS SOLID FERMENTATION OF A WATER-CLEANING BACILLUS STRAIN FROM A SWINE FERMENTATION BED

为解决养猪场污染物问题,从猪场生物发酵床中分离10株芽孢杆菌,用养猪污水进行培养,筛选出净化污水能力最强的一株,通过鉴定其为蜡状芽孢杆菌,并优化了该菌固体发酵培养基及固体发酵工艺条件。结果表明:此蜡状芽孢杆菌能使养猪污水中COD和氨氮分别降低47.1%和54.4%。优化后的培养基组分和条件为m(豆粕)∶m(稻壳)∶m(麸皮)=2∶9∶9(样品干重比),含水率为50%,KH2PO4含量为1.5%,MgSO4·7H2O含量为0.1%,初始pH为6.5。3%的菌株接种量在发酵温度为30℃的培养基中生长状况最佳,24 h后菌落数达到3.8×108CFU/g。

To solve the intensive pollution of piggeries,a total of 10 strains of Bacillus were selected from a swine fermentation bed,and cultured with the swine wastewater. The total genomic DNA of one strain showing the highest ability in swine wastewater purification was extracted and it was classified as Bacillus cereus. The basic conditions of the solid fermentation medium and whole process were then studied. Results showed that 47. 1% of COD and 54. 4% of ammonium in the swine wastewater were degraded by the Bacillus cereus. The optimal medium conditions for the Bacillus cereus was as follows: soybean meal,rice husk and bran were homogenized at a ratio of 2∶ 9∶ 9( dry weight),moisture content and pH were 50% and 6. 5,the KH2PO4 and MgSO4·7H2O content was 1. 5% and 0. 1%,respectively. The Bacillus cereus grew best with the fermentation temperature of 30 ℃ and the inoculums content of 3%,and the bacterium population reached 3. 8 × 108 CFU /g after 24 h.