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

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1.55×1010 CFU/mL，Ⅱ类废水活菌数为6.60×1010 CFU/mL.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3.80×1010 CFU/mL和9.20×1010 CFU/mL）；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1.60×1010 CFU/mL）和2.0%（活菌数为6.40×1010 CFU/mL）.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（2.0×108 CFU/mL），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. 

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

Bacillus mucilaginous was used as the experimental strain to produce dissolving potassium liquid biofertilizer using food waste-recycling wastewater as fermentation substrate.The culture conditions were optimized by the orthogonal and single factor methods.The results showed that 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 1.55×1010 CFU/mL, wastewater Ⅱ 6.60×1010 CFU/mL).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 3.80×1010 CFU/mL, wastewater Ⅱ 9.20×1010 CFU/mL); 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 1.60×1010 CFU/mL and 6.40×1010 CFU/mL, 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.