Actinomycetes from Tropical Limestone Caves
Nanthavut Niyomvong, Wasu Pathom-aree, Arinthip Thamchaipenet andKannika Duangmal* Author for corresponding; e-mail address: fscikkd@ku.ac.th
Volume: Vol.39 No.3 (JULY 2012)
Research Article
DOI:
Received: 4 November 2011, Revised: -, Accepted: 28 May 2012, Published: -
Citation: Niyomvong N., Pathom-aree W. and Duangmal A.T.A., Actinomycetes from Tropical Limestone Caves, Chiang Mai Journal of Science, 2012; 39(3): 373-388.
Abstract
The cultivable actinomycetes from tropical limestone caverns at Khao No-Khao Kaeo karst, Thailand, were investigated. In total, 276 actinomycetes were isolated from 10 soil samples using different selective isolation procedures. The predominant actinomycetes from all samples were members of the genus Streptomyces (94.6%) as they contained LL-diaminopimelic acid (A2pm) in their whole cell hydrolysates. The remaining 15 isolates (5.4%), rich in meso-A2pm in whole cell hydrolysates were characterized by 16S rRNA gene sequencing. They were shown to represent strains from 8 different genera namely Actinomadura, Actinoplanes, Gordonia, Microbispora, Micromonospora, Nocardia, Nonomuraea and Saccharopolyspora. A good agreement was found between the results based on morphology, presence of meso-A2pm and 16S rRNA gene phylogeny. Microwave treatment of soil samples was found to promote the isolation of rare actinomycetes. Successful isolation of members of the genus Actinomadura and Saccharopolyspora from caves was reported for the first time. This study confirms significant diversity of cultivable actinomycetes from neglected habitats such as limestone caves in Thailand.