海洋源拮抗细菌的分离、筛选及1株拮抗芽孢杆菌的鉴定

Isolation and screening of marine antagonistic bacteria and identification of a strain of antagonistic Bacillus sp.

对来自于不同海域的红树树皮、海苔(海洋生物样)和海泥(海洋底质)样品进行细菌分离,并采用管碟法测试了分离出的海洋细菌对金黄色葡萄球菌Staphylococcus aureus、枯草芽孢杆菌Bacil-lus subtilis、大肠杆菌Escherichia coli、白色念珠菌Candida albicans、黑曲霉Aspergillus niger和绳状青霉Penicillium funiculosum等6种指示菌的抑菌活性,对其中1株具有较强抑菌活性的NB 7.2海洋细菌进行了菌种鉴定。研究结果表明:从样品中共分离出72株海洋细菌,从中筛选出具有抑菌活性的细菌为12株(下文称拮抗细菌),占总分离菌数的比率为16.7%,其中,芽孢杆菌为7株(占9.7%),革兰氏阴性杆菌为5株(占6.9%)。指示菌被拮抗细菌抑制的强弱程度依次为:革兰氏阳性菌>革兰氏阴性菌>丝状真菌。拮抗细菌中芽孢杆菌的抑菌作用强于革兰氏阴性杆菌,来源于红树林海域样品的拮抗细菌平均检出率最高,为25.3%。经形态、生理生化和16SrDNA序列的分析,NB 7.2海洋细菌被鉴定为枯草芽孢杆菌Bacillus subtilis。

72 strains of marine bacteria were isolated from marine samples collected at harbors and mangrove in Guangdong. These strains were screened for antimicrobial activities on Staphylococcus aureus, Bacillu subtilis , Escherichia coli , Candida albicans , Aspergillus niger and Penicillium f uniculosum using cylinder plate method. The results show that 12 strains have antimicrobial activity, accounting for 16.7% of the total in which 7 strains are Bacillus spp. （accounting for 9. 7%） and 5 strains are Gram-negative rod-shaped bacteria （accounting for 6. 9%）. The effects of antimicrobial activity produced by the antagonistic bacteri〉 strains on the tested microorganisms are in the order of Gram-positive bacteria^Gram-negative bacteria） filamentous fungi, and antimicrobial activity of marine spore-producing bacteria is stronger than that of th, Gram-negative bacteria. The mean isolation rate of the marine antagonistic bacteria strains with antimicrobial activitie from the mangrove samples is the highest, up to 25.3%. The strain NB7.2 with strong antimicrobial activit, is identified as Bacillus subtilis according to its morphological, physiological and biochemical characteristics and 16S rRNA sequence analysis.