芽孢杆菌L15菌株发酵培养条件的优化

Optimization of fermentation and culture conditions of Bacillus L15 strain

芽孢杆菌L15菌株能有效降低刺参Apostichopus japonicas养殖水中的化学耗氧量(COD)和氨氮(NH+4-N)含量,促进刺参生长,为大量发酵培养L15菌株并降低培养成本,以豆粕、麦麸、玉米酒糟、棉籽粕为碳、氮源,对发酵培养L15菌株的最佳碳、氮源及其配比和最佳发酵条件(如装液量、接种量、转速等)进行了初步优化研究。结果表明:培养芽胞杆菌L15菌株的最佳碳、氮源为麦麸和豆粕,最佳添加量分别为3、2 g/L;最佳发酵培养条件为装液量1/3、接种量1%、转速160 r/min;在最佳培养基和最适培养条件下,发酵培养的L15菌株细菌数量可达1011cfu/m L,与用2216E培养基培养的L15菌株相比,在实验室条件下,对海参底泥COD的去除率虽无明显变化,但培养成本却降低了91%。研究表明,用豆泊和麦麸作为培养基培养L15菌株具有可行性,不仅细菌数量达标,且培养成本显著降低。

Bacillus strain L15 was isolated from sea cucumber Apostichopus japonicas culture ponds in Dalian and found to be effectively reduced levels of COD and NH4^＋ -N in the sea cucumber ponds and significantly promoted the growth of sea cucmber. The strain L15 was cultured in media of soybean meal,wheat bran,corn distillers, cottonseed meal to optimize carbon and nitrogen sources and fermentation conditions including loading volume, inoculation quantity,and rotational speed in order to reduce cost in mass fermentation cultivation of L15 strain. The results showed that the best fermentation culture of L15 strain was observed under conditions of soybean meal and wheat bran as carbon（3 g/L） and nitrogen （2 g/L） sources,1/3 loading volume,1 % inoculation quantity, and rotational speed of 160 r/min,with density of 10^11cfu/mL,and without significant difference in degradation rate of COD in the sea cucumber pond sediments by the cultivated L15 strain compared with 2216E medium cultivation of L15 strain under the condition of indoor experiments. However,the cultivation cost was found to be decreased by 9 1 % , indicating that it is feasible to cultivate L15 strain for use of beans and wheat bran to meet bacterial number require-ment.