Isolation and Application of Thermophilic and Psychrophilic Microorganisms in the Composting Process

Abstract

Because temperature is a limited factor in compost process, we attempted to isolate and screen efficient themophilic and psychrophilic strains from composts and soils adapting to high and low temperature, respectively. Firstly, two cellulose-effectively-decomposing thermophilic bacteria, HNS39 and HNC41, were screened from 13 thermophilic compost samples and one soil sample from tropical rain forest. By addition of microbial agents with single HNS39, HNC41, or their mixture (1:1 v/v), the progress of composing was more effectively improved with HNS39. According to 16S rDNA gene sequencing and its growth characteristics, HNS39 was identified as Geobacillus sp. Meanwhile, the psychrotrophs strains of B6-38, B10-40, B10-44 isolated, could rapidly reproduce and effectively degrade organic compounds with highest enzyme activity in low temperature from 10 samples collected from sewage sludge, poultry manure and paddy soil. It was indicated that cold-adapted bacteria had a better effect on the raise of composting temperature, especially B6-38 with the highest protease activity of 46.08 U/ml. It grew fast and had good ability of enzyme production and strong organic degradation capabilities at 15 °C. By identification, Strain B6-38 was associated with Aeromonasa sp. Therefore, the research was fully shown that the isolated thermophilic and psychrophilic microorganisms had high potential of application in the composting under high and low temperature.