Biological characteristics and classification of thermophilic actinomycetes showed extracellular hydrolytic enzymes producing ability isolated from compost

Vietnam - Russia Tropical Centre, 63 Nguyen Van Huyen, Cau Giay, Ha Noi, Vietnam

^* Corresponding author: tuyendodhkh@gmail.com

Abstract

Compost is a highly humified organic fertilizer, rich in nutrients and a source of a variety of aerobic microorganisms, including actinomycetes, which develop in response to different levels of temperature, humidity, oxygen and pH. Microbes growing on the compost are believed to have the ability to produce extracellular hydrolytic enzymes. The purpose of this study was to determine the ability of thermophilic actinomycetes XM21 isolated from compost in producing hydrolytic enzymes, namely cellulase, amylase, protease, and lipase. The confirmation tests of hydrolytic enzymes-producing ability were conducted by inoculating the microbes into media containing cellulose, starch, gelatin and tween 80, using the method of disc diffusion. The results showed that strain XM21 capable of extracellular enzymes producing, such as cellulase, protease, amylase, lipase. Strain XM21 can grow well with high cellulase activity in a wide range of temperature between 30-55oC, optimum at 45oC. The strain can grow well on different media, utilized carbon sources with pH 5-10, and salinity of 0-5%. On the agar plate, the strain has white aerial mycelia, the mature spore chains appeared spirals, moderately long, bearing 10 to 35 spores each. Based on the biological characteristics and phylogenetic analysis of 16S rDNA, it can be concluded that strain XM21 is close to Streptomyces flavovariabilis (98, 12%), hence identified as Streptomyces flavovariabilis XM21.