Characterizing thermophilic bacteria isolated from surface layers of compost in the pre-decomposition stage

Thermophilic bacteria are potential bacteria for degrading organic waste. This study aims to isolate and characterize thermophilic bacteria in surface compost in the pre-decomposition phase of PT. Great Giant Pineapple Compost Plant. This study used an exploratory descriptive method including isolation, purification, macroscopic characterization, microscopic characterization, an enzymatic activity test, and determination of the Enzymatic Index (EI) value. The results of this study obtained 7 isolates of thermophilic bacteria that have irregular and spreading, and round shapes with flat, raised, and umbonate elevations.  Colony edges are undulate, entire, lobate, and irregular with cream color.  Isolates ZS1, ZS2, ZS4, and ZS5 have a monobacillary cell shape, while isolates ZS3, ZS6, and ZS7 have a streptobacillary cell shape; all Gram positive except ZS1 and only ZS1 does not form spores. All isolates of thermophilic bacteria were able to produce catalase enzyme, protease enzyme except isolate ZS7; amylase except isolate ZS5; and cellulase in isolates ZS1, ZS5, ZS6, and ZS7.  The highest Enzymatic Index (IE) of protease, amylase, and cellulase in order were ZS4 with a value of 6.1, ZS2 with a value of 4.37, and ZS1 with a value of 6.5.