Bakteri memegang peranan penting dalam proses dekomposisi serasah daun kratom di kawasan danau manuk bungkul dalam menghasilkan bahan organik. tujuan dari penelitian ini adalah mengidentifikasi genus bakteri pada serasah daun kratom (mitragyna speciosa) yang terdekomposisi di danau manuk bungkul kecamatan sembakung kabupaten nunukan. penelitian ini dilaksanakan pada bulan september sampai desember 2019. metode yang digunakan yaitu experimen, deskriptif dan kuantitatif melalui 2 tahap yaitu pengambilan serasah kratom di danau manuk bungkul dan identifikasi bakteri di laboratorium balai karantina ikan pengendalian mutu dan keamanan hasil perikanan (bkipm) kelas ii tarakan. hasil identifikasi bakteri serasah daun mitragyna speciosa yang terdekomposisi sebanyak 4 genus bakteri yaitu actinobacillus sp., aeromonas sp., bacillus sp., dan enterobacteria sp. bakteri yang paling dominan ditemukan yaitu aeromonas sp. rata-rata hasil laju dekomposisi yaitu 0,19 – 0,27 gram/hari. kata kunci: bakteri, danau manuk bungkul, dekomposisi, mitragyna speciosa, serasah

Bacteria play an important role in the process of decomposition of kratom leaf litter in the manuk bungkul lake area in producing organic material. the purpose of this study was to identify the bacterial genus in decomposed kratom (mitragyna speciosa) leaf litter in manuk bungkul lake, sembakung district, nunukan regency. this research was conducted in september to december 2019. the method used was experimental, descriptive and quantitative through 2 stages, namely the collection of kratom litter in manuk bungkul lake and bacterial identification in fish quarantine station laboratory of quality control and safety of fisheries (bkipm) class ii tarakan. the results of identification of mitragyna speciosa leaf litter bacteria were decomposed by 4 genera of bacteria namely actinobacillus sp., aeromonas sp., bacillus sp., and enterobacteria sp. the most dominant bacteria found was aeromonas sp. the average decomposition rate is 0.19 – 0.27 gram/day. keywords: bacteria, manuk bungkul lake, decomposition, mitragyna speciosa, litter