Screening of actinomycetes from marine sediments for their potential to produce bioactive secondary metabolites

• Main Authors: Kuan-Ting Chen, 陳冠廷
• Other Authors: Jimmy Kuo
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/2nmz7t

碩士 === 國立東華大學 === 海洋生物研究所 === 106 === It is acknowledged that marine actinomycetes have enormous potential as producers of novel natural products with various biological activities. In this study, marine actinomycetes inhabiting marine sediments, collected from Kaohsiung Harbor and Bashi channel, were screened for their abilities in producing secondary metabolites with antimicrobial activity. To increase the abundance of actinomycetes, the sediment samples were pretreated by freezing for seven days. Marine actinomycetes were then enriched and isolated with five different selective media by using agar-based culture techniques. Our results showed that Gause I agar media were the most suitable media for actinomycete isolation. A total of 811 actinomycetes were isolated from six marine sediment samples. 70 isolates (8.63%) showed antimicrobial activity using agar block methods against at least one of six test strains. 26 isolates that displayed high antimicrobial activity were selected for 16S rDNA sequencing. Phylogenetic analysis of the sequences indicated these isolates are members the following four actinomycetal genera: Streptomyces (21), Actinoalloteichus (2), Saccharomonospora (2), and Nocardiopsis (1). Fourteen isolates viz., KS12-TJ12, BJ01-PL13, BJ01-PL19, BJ01-PL22, BJ02-PL34, BJ03-PL66, BJ02-PL78, BJ01-PLf10, BJ01-PLf31, BJ02-PLf54, BJ03-PLf58, BJ03-PLf59, BJ03-PLf63, and BJ03-PLf82, which have high cytotoxicity against cancer cell (HL-60, K-562 and MOLT 4) as well as antimicrobial activity were good candidates for further natural product isolation and characterization of the bioactive components.