杀线虫解淀粉芽胞杆菌Sneb709与费氏中华根瘤菌Sneb183共培养发酵条件优化

根结线虫可引起作物发生严重的土传病害,生物防治是持续控制此类病害的有效措施.本实验室前期筛选获得多株杀线虫活性的芽胞杆菌和根瘤菌,本研究将解淀粉芽胞杆菌Sneb709与费氏中华根瘤菌Sneb183进行共培养后发现,共培养发酵液对南方根结线虫2龄幼虫J2活性显著提高,因此本文利用响应面法对其发酵条件进行优化,获得更好的生...

Optimization of Fermentation Conditions for Co-culture of Nematocidal Bacillus amyloliquefaciens Sneb709 and Sinorhizobium fredii Sneb183

Root-knot nematodes can cause serious soil-borne diseases of crops, and biological control is an effective measure to sustainability control such diseases. Several strains of Bacillus and Rhizobium with nematicidal activity were obtained in previous work of our laboratory. In this study, Bacillus amyloliquefaciens Sneb709 and Sinorhizobium fredii Sneb183 were co-cultured, and the co-culture fermentation broth had significantly improved activity against Meloidogyne incognita second-stage juveniles (J2). To obtain better biocontrol effects, the fermentation conditions were optimized by response surface methodology. Taking the corrected mortality rate of J2 as an indicator, the single factor method, steepest climbing method and response surface method are used to design and optimize the fermentation broth composition and culture conditions of the co-cultured strains. The most suitable medium composition of the co-culture fermentation broth was determined as follows:sorbose 1.98 g/L, soy flour 1.06 g/L, peanut meal 2.08 g/L. The optimal fermentation conditions were as follows:temperature 30.4℃, initial pH 6.49 and liquid volume 103.15 mL. After the two strains were co-cultured with optimized conditions, the toxic activity of the fermentation broth on J2 was significantly improved, with the mortality of 84.17%. After verification in the fermenter, the toxic activity of the co-culture fermentation broth increased by 24.72%. This result provides a theoretical basis for subsequent studies on separation and extraction of active products of co-cultured strains and the industrialization of nematocidal biocontrol bacteria.