Changes in microbial flora during the fermentation process of compost for Agaricus blazei Murrill cultivation

Abstract

Agaricus blazei Murrill is cultivated with compost as a medium. The fermentation process of the compost was investigated by colony numbers of microorganisms （fungi, bacteria and actinomycetes）, PCR-DGGE analysis of bacterial flora, C/N ratio, and fresh yield of the fruit bodies using compost at each fermentation stage. The numbers of bacteria and actinomycetes peaked on 30 days, whereas the number of fungi was the highest at the beginning of fermentation. PCR-DGGE analysis revealed that bacterial flora was changing until day 30 and then became fixed. The C/N ratio decreased from 90 to 40-50 in 30 days and was constant thereafter. The yield of A. blazei Murrill fresh fruit bodies was less than 5 g/bin when composts fermented for 0-20 days were used, but over 26 g/bin with composts at fermented for 30-41 days. Therefore, compost in which bacterial flora and C/N ratio are stable appear to be an appropriate medium for A. blazei Murrill cultivation. These results suggest that we can use not only C/N ratio but also bacterial flora to evaluate the maturation of compost.