胶质芽孢杆菌(Bacillus mucilaginosus)在餐厨垃圾废水中生长条件优化

Optimization of Culture Conditions for Bacillus mucilaginosus Growing in Food Waste-Recycling Wastewater

为了探讨餐厨垃圾废水用作发酵基质生产液态解钾菌肥的可行性,选用胶质芽孢杆菌(Bacillus mucilaginosus)作为试验菌种,采用正交和单因素方法对相关生长因素进行了优化.结果表明,在餐厨垃圾废水中培养胶质芽孢杆菌经过3 d的调整期后进入对数生长期,6~7 d时活菌数达到最大,Ⅰ类废水活菌数为1.55×10^(10)CFU/m L,Ⅱ类废水活菌数为6.60×10^(10)CFU/m L.以Ⅱ类废水为基质进行正交试验确定的较优培养条件为pH=7、温度30℃、摇床转速160 r/min、接种量2.0%(V/V).废水的pH和盐分对胶质芽孢杆菌的生长代谢影响极为显著:最适初始pH为7(活菌数为3.80×10^(10)CFU/m L和9.20×10^(10)CFU/m L);随着ρ(NaCl)的增加,活菌数先升高后快速降低,最适ρ(NaCl)为4 g/L.Ⅰ类和Ⅱ类废水的最佳接种量分别为1.5%(活菌数为1.60×10^(10)CFU/m L)和2.0%(活菌数为6.40×10^(10)CFU/m L).研究显示,胶质芽孢杆菌在餐厨垃圾废水中经过培养后可达到GB 20287—2006《农用微生物菌剂》中液态菌肥的活菌数(2.0×10~8CFU/m L),经湿热处理后的Ⅱ类废水对胶质芽孢杆菌的生长有明显的促进作用.

Bacillus mucilaginous was used as the experimental strain to produce dissolving potassium liquid biofertilizer using food wasterecycling wastewater as fermentation substrate. The culture conditions were optimized by the orthogonal and single factor methods. The results showed that B. mucilaginous cultured in the food waste-recycling wastewater reached logarithmic growth stage in as short as 3 days of adaptation period,and the number of strains reached the maxima on day 6-7（wastewater I 1. 55 ×10^10 CFU/m L,wastewater II 6. 60 ×10^10CFU/m L）. The optimal culture conditions were pH = 7,T = 30 ℃,shaking speed 160 r/min,and inoculums of 2. 0%（V/V） as determined by orthogonal experiment with wastewater II as fermentation substrate. pH and salt concentration of the wastewater had a great influence on the growth and metabolism of B. mucilaginous; the optimal pH for B. mucilaginous growth was pH = 7（wastewater I 3. 80 ×10^10CFU/m L,wastewater II 9. 20 ×10^10 CFU/m L）; with the increase of ρ（NaCl）,the strain numbers first increased and then steeply decreased,and the optimal ρ（NaCl） for bacterial culture was 4 g/L. The optimum inoculation amount was 1. 5% for wastewater I and 2.0% for wastewater II,with strain numbers of 1. 60 ×10^10 CFU/m L and 6. 40 ×10^10 CFU/m L,respectively. The number of living B.mucilaginous cultivated in waste-recycling wastewater could reach the standard number level of living bacterium in liquid bacterial manure set by the Ministry of Agriculture of China. The wastewater II obtained by hydrothermal treatment of food waste could obviously promote the growth of B. mucilaginous.