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根据菌体的形态、生理生化特征以及16s rDNA序列分析结果,将一株分离自中国海南东寨港红树林保护区红海榄根际土壤的细菌菌株DH-11鉴定为芽孢杆菌属的短小芽孢杆菌(Bacillus pumilus strain DH-11)。菌株DH-11是一种革兰阳性短杆菌,大小约为(0.5～0.6)μm×(0.7～1.5)μm,卵圆形芽孢侧端生。其细胞中的主要脂肪酸为Iso-C15∶0和Anteiso-C15∶0,它们的含量占菌体总脂肪酸含量的47.49%和26.21%,其它脂肪酸还包括Iso-C17∶1(7.27%)、Anteiso-C17∶0(6.92%)、C16∶1 N Alcohol(3.45%)以及C16∶0(2.33%)等。与已报道的短小芽孢杆菌菌株B.pumilus ATCC 7061的不同之处在于:菌株DH-11不能利用木糖和甘露醇产酸,且硝酸盐还原呈阳性。进一步的研究显示:菌株DH-11在改良马铃薯培养基中培养时,获得的培养液及其提取浸膏不能抑制革兰阴性细菌Escherichia coli和Pseudomonas aeruginosus的生长,但对革兰阳性菌Staphylococcus epidermidis、Staphy-lococcus aureus、Bacillus subtilis和Sarcina lutea的生长具有一定的抑制作用:其中发酵液浸膏1和浸膏2对上述菌株的最低抑菌浓度(MIC)分别为500.0和250μg/mL,浸膏2还可抑制真菌Candida albicans的生长,其MIC为500μg/mL。
According to the morphological, physiological and biochemical characteristics of bacteria and 16s rDNA sequence analysis, a bacterial strain DH-11 isolated from Rhizophora stylosa rhizosphere soil of Mangrove Reserve in Dongzhaigang, Hainan, China was identified as Bacillus pumilus (Bacillus pumilus strain DH-11). The strain DH-11 is a Gram-positive Brevibacterium and has a size of (0.5-0.6) μm × (0.7-1.5) μm. The main fatty acids in the cells were Iso-C15: 0 and Anteiso-C15: 0, accounting for 47.49% and 26.21% of the total fatty acids in the cells. Other fatty acids also included Iso-C17: 1 C17: 0 (6.92%), C16: 1 N Alcohol (3.45%) and C16: 0 (2.33%) and the like. The difference from the reported B. pumilus ATCC 7061 is that strain DH-11 can not acidify with xylose and mannitol, and nitrate reduction is positive. Further studies showed that when the strain DH-11 was cultured in modified potato culture medium, the culture medium and its extract could not inhibit the growth of Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosus, but Gram-positive bacteria Staphylococcus epidermidis, Staphy-lococcus aureus, Bacillus subtilis and Sarcina lutea. The minimum inhibitory concentrations (MICs) of fermentation broth extract 1 and 2 against the above strains were 500.0 and 250 μg / mL, respectively, and extract 2 It also inhibited the growth of the fungus Candida albicans with a MIC of 500 μg / mL.