We prepared charcoals from bamboo, scrap wooden formwork and corn-cobs. Each of these charcoal powders was mixed with rice bran as a nutrient in a weight ratio of 1: 1.15.(Rice bran had previously been used as a model biomass waste for composting.) The moisture content of the mixture was adjusted to 65 %. Aerobic complex microorganisms were added to the biomass waste mixture to seed the composting. Samples were maintained in ambient air (RH 53 %, 23°C) and stirred vigorously with a spatula once a day for aeration. Scanning electron microscopy revealed microorganisms on the surface of the charcoal and in the mouths of the charcoal pores.Measurement of adenosine triphosphate concentrations of the samples revealed that the microorganisms had proliferated in the systems containing charcoal.
It was suggested that this proliferation was attributed to supplying abundant oxygen for microorganisms because the charcoal has a lot of pores. Another reason why the charcoal facilitated microorganisms proliferation might be that the microorganisms on the surface of the charcoal were able to be supported in the pores of a sub-micron scale in the charcoal as a matrix might be.