Bacterial Diversity on the Application of Methanotrophic Bacteria in Rainfed Rice of Kupang Regency, East Nusa Tenggara, Indonesia

Abstract

. Paddy fields are the main anthropogenic source of methane emissions as a greenhouse gas that causes global warming. In this research, methanotrophic bacteria as biological fertilizers are used to reduce methane gas in rainfed rice fields and study the diversity of bacteria based on the application of these fertilizers. This research began with the cultured of the bacterial cultures of Methylocystis rosea BGM 1, Methylocystis palvus BGM 3, M. capsulatus BGM 9 and Methylobacter sp. SKM 14. Furthermore, culture production and application are carried out in rainfed rice fields. The treatments consisted of: (1) NPK 100% (P1), (2) NPK 50% (P2), (3) without fertilizer application (P3), (4) NPK 100% + Metanotrophs (P4), (5) NPK 50% + Metanotrophs (P5), and (6) Metanotrophs (P6). Analysis of the diversity of bekteri using the Deanaturing Gradient Gel Eltrophoresis (DGGE) technique. The study of bacterial diversity based on the 16S rRNA gene showed that the proteobacteria genus dominated the habitat consisting of the gammaproteobacteria, alfaproteobacteria and deltaproteobacteria classes. the bacterial diversity as fertilization P5 and P6 treatments the highest similarity, followed by treatments P4, P2 and P3, and P1. Dendrogram 90 DAP shows NPK fertilization treatment and NPK fertilization with methanotroph the same diversity of bacteria in the final phase of maturation, whereas control treatment without fertilization and treatment with methanotroph have different bacterial diversity. The treatments P1 and P2 have the highest similarity, followed by treatments P4 and P5, P3, and P6.