A special type of compost called Satsuma soil is made in Kagoshima City, Japan, using a unique hyper-thermal process with high temperatures. Scientists studied the bacteria in this compost and compared it to other composts and sludges. They found that the bacterial community in the hyper-thermal compost was very different from the original sludge, with specific types of bacteria becoming more common. These bacteria were not found in other composts made with the hyper-thermal compost as a starter. This shows that the hyper-thermal composting process creates a distinct bacterial community structure.