甲基营养型芽胞杆菌BMF 04固态发酵条件优化及其对黄瓜幼苗生长的影响

甲基营养型芽胞杆菌Bacillus methylotrophicus BMF 04是本实验室从连云港海域分离纯化得到的对多种植物病原真菌有较强抗菌作用的优良生防菌株。为进一步开发应用该菌株，以细菌总数和芽胞率为指标，通过单因素和响应面试验设计，优化固态发酵培养基配方和发酵条件，采用室内盆栽试验，测定发酵物对黄瓜幼苗生长的影响。结果表明，优化后菌株BMF 04固态发酵培养基配方为豆粕92.5%，菌糠6.7%，硝酸铵0.6%，氯化钠0.2%；发酵条件为pH 7，温度32℃，接种量15%（浓度为10⁸细胞/mL），料水比1：1，培养时间68 h。优化后，细菌总数可达6.61×10¹⁰细胞/g，芽胞率为90.7%。发酵物与土壤以1：250质量比混和时，能显著提高黄瓜幼苗的株高、茎粗、鲜重及根须数，对黄瓜幼苗生长具有明显的促进作用。

Optimization of Solid-state Fermentation Conditions of Bacillus methyltrophicus BMF 04 and Its Effect on the Growth of Cucumber Seedlings

Bacillus methylotrophicus BMF 04 is an excellent antibacterial strain with strong antagonism against a variety of plant pathogenic fungi isolated and purified from the Lianyungang Sea.To further develop the application of this strain,,using the total number of bacteria and budding cell rate as indicators,the solid-state fermentation medium formulation and fermentation conditions were optimized by designing single-factor and response surface tests,and the effect of the fermentate on the growth of cucumber seedlings was determined by indoor potting experiments.The optimized solid-state fermentation medium formulation of BMF 04 strain was 92.5%soybean meal,6.7%bran,0.6%ammonium nitrate,0.2%sodium chloride.The optimal fermentation conditions were pH 7,temperature 32℃,inoculation amount 15%(concentration 108 cells/mL),feed-water ratio 1:1 and culture time 68 h.After optimization,the total bacteria amount could reach 6.61×10¹⁰ cells/g,and the budding cell rate was 90.7%.When the fermentation was mixed with soil at 1:250 mass ratios,it significantly improved the height,stem thickness,fresh weight and number of root whiskers of cucumber seedlings,indicating the fermentation had an obvious effect on the growth of cucumber seedlings.