云南干热环境可培养高温放线菌多样性及产纤维素酶活性评价

Diversity of culturable thermophilic actinobacteria and their producing cellulase activity in several dry-hot environments in Yunnan Province

【目的】探索云南东川干热河谷、元谋土林以及昆明周边高温堆肥、热泉等环境可培养高温放线菌的多样性及其产纤维素酶的潜力。【方法】利用稀释涂布平板法从采集于上述环境的样品中分离得到菌株500余株,通过形态去重复后对300余株进行16SrRNA基因测序分析,并对获得的菌株利用刚果红染色的方法进行纤维素酶活性初步筛选。【结果】分离到的菌株共分布于放线菌纲下9个亚目15个科33个属,其中候选新属2个、候选新种3个。451株菌的纤维素酶筛选结果显示57%具有纤维素酶活性,其中链霉菌、小单孢菌、野野村氏菌在纤维素酶活性菌株中占较大比例。【结论】云南干热环境下蕴含着丰富的放线菌资源,纤维素酶初步筛选显示出了良好的降解活性,为下一步的深入研究提供良好的菌源。

[Objectivel This study focus on the diversity of culturable thermophilic actinobac- teria isolated from Dong Chuan dry hot river valley, Yuan Mou soil forests, and some high-temperature composts, hot springs nearby Kunming in Yunnan province, and exploring their cellulase producing activity. [Methods] Over five hundreds strains were isolated by the plate dilution method. After dereplication and removing the similar strains based on col- ony-characteristics, more than three hundreds strains were sequenced for further research. The cellulase producing activity of 451 strains were further detected by Congo red solution. [Re- sults] BLAST analysis of the partial 16S rRNA gene sequences revealed that these strains have the highest similarity with 33 described genera, which were distributed in 15 families of 9 suborders. Among of them, five actinobacterial strains were selected as potential candidates for further polyphasic taxonomic research, based on the lower similarities of 16S rRNA gene sequences. Cellulase screening results showed that the positive rate was about 57% in total 451 strains. Most of them were distributed in three genera of Streptornyces, Micrornonospora and Nonomuraea. [Conclusion] There are considerable diversity of culturable thermophilic acti- nobacteria in dry hot environments of Yunnan province. Meanwhile, these strains exhibited higher positive rate and stronger activity of cellulase, which will provide high-quality experi- mental materials for future research.