红树林样品不经分离的微生物群体培养物生物活性研究

Bioactivity survey of natural microbial consortium from mangrove

从海南、广西与广东三省的红树林区采集了181个样品,不进行微生物分离而直接作发酵剂接种到发酵培养基进行发酵,取发酵上清液进行抗细菌、抗真菌与肿瘤细胞毒活性的测定。同时对样品进行可培养微生物的分离与生物活性测定。结果显示:不同样品类型的生物活性差异较大。在15个具有强抗活性的样品中,有5个样品分离到的单株菌均无任何生物活性,说明这5个样品的生物活性可能是由微生物的群体作用产生的,也可能是某种没有培养出的微生物产生的。初步表明了探索微生物混合培养获得生物活性代谢产物的可能性。

Microbial natural products have been mainly acquired by pure culture. While in nature, different - microorganisms in one habitat may work together as a whole to produce special secondary metabolites to adapt to their environments. ＂Quorum-sensing＂ is a way that they would use. A microbial consortium is like a mnlti-cellular individual that different microorganisms interact with each other to fulfill a special function. A marine fungus only produce antibiotics when a bacterium co-cuhured （Cueto et al, 2001 ）; and some traditional Chinese fermentation food are produced by mixed culture. These inspired us that directly using natural microbial consortium instead of isolate the individual microorganism may be a worth to risk in search for bioactive products. In this research, One hundred and eighty one samples were collected from three mangrove areas of Hainan, Guangxi and Guangdong, in China, which were fermented directly and evaluated for their anti-bacteria, anti-fungi and anti-cancer cell activities. Fifteen samples with high activities were further studied. Microorganisms were isolated from these 15 high bioactive samples and re-detected for their bioactivity, among which, microorganisms isolated from 5 samples that numbered 1106, 1122, 1116, 1214 and 1305 didn＇t show any activity although the un-isolated samples themselves showed high bioactivity. Four strains were isolated from one sample of number 1146. Among these strains, one strain showed the same bioactivity targets as the sample itself , but lower activity of anti-fungi than the sample itself. The other three strains didn＇t show any bioactivity. Microorganisms isolated from three samples that numbered 1161, 1123 and 1111, changed their initial bioactivity targets. These results suggested that natural microbial consortium culture have the potential to produce bioactive metabolites. It is supposed that some uncultured microorganisms or the community action may be the reason for their activity. This is an initial step on using microbial consortium to produce bioactive metabolites.