豆渣降解高温菌的筛选及应用

Screening and Application of Thermophilic Bacteria for Degrading Soybean Dregs

为了在高温条件下降解豆渣,从马粪、猪粪、豆渣以及生活污泥中筛选分离高温菌,初步筛选后获得7株可在70℃条件下利用豆渣生长的细菌,通过16S rDNA鉴定确定其分别属于Geobacillus toebii、Geobacillus sp.、Methylobacterium sp.和Thermus thermophilus 4个类别的属种,其中Geobacillus toebii(G.T1)对豆渣的降解率最高(4.8%)。研究表明,高温菌株G.T1的最佳增殖培养条件为生长温度65℃,初始培养基pH值7.5,菌株24 h内可达到生长稳定期。将菌株G.T1转接至豆渣(含5%的黄浆水污泥)中保温70℃好氧发酵5 d,结果表明,发酵5 d后,试验组的碳氮比(C/N)降低至14.43,低于空白(CK);试验组的种子发芽指数为135.00%,远高于CK(86.42%);此外,作为有机肥重要营养指标的氮、磷、钾元素含量,在试验组中分别是27.72、7.69、17.92 g/kg,比CK分别提升了18.46%、25.04%、22.74%。因此,高温菌株G.T1不仅能加快豆渣的腐熟进程,而且还有助于提高有机肥产品中氮、磷、钾营养元素的含量。

In order to degrade soybean dregs in high temperature,thermophilic bacteria were screened from soybean dregs,horse manure,pig manure and domestic sludge.The results showed that 7 thermophilic bacteria strain were gained,which could utilize soybean dregs to grow at 70℃.Through 16S rDNA identification,they belonged to Geobacillus toebii,Geobacillus sp.,Methylobacterium sp.and Thermus thermophilus,respectively.Among them,Geobacillus toebii(G.T1)was the best for degrading soybean dregs(4.80%).The optimal growth temperature for strain G.T1 was 65℃,and optimal initial pH value was 7.5,the strain reached stable growth phase within 24 h.The strain G.T1 was inoculated to soybean dregs(including 5%soybean water sludge)and fermented at 70℃for 5 d,the carbon-nitrogen ratio(C/N)of the experimental group decreased to 14.43 after 5 d of fermentation,which was lower than the blank(CK).Furthermore,the seed germination index of the experimental group was 135.00%,far higher than that of the CK(86.42%).In addition,as important nutritional indicators of organic fertilizers,the contents of nitrogen,phosphorus and potassium were 27.72,7.69 and 17.92 g/kg in the experimental group,respectively,which were 18.46%,25.04%and 22.74%higher than those in the CK.Therefore,strain G.T1 could not only promote the maturity process of soybean dregs,but also improve the contents of nitrogen,phosphorus and potassium nutrients.