Emergence and behaviors of acid-tolerant Janthinobacterium sp. that evolves N sub(2O from deforested tropical peatland)

Using a soilless culture system mimicking tropical acidic peat soils, which contained 3 mg of gellan gum and 0.5 mg NO sub(3) super(-)-N per gram of medium, a greenhouse gas, N sub(2O emitting capability of microorganisms in acidic peat soil in the area of Palangkaraya, Central Kalimantan, Indonesia, was investigated. The soil sampling sites included a native swamp forest (NF), a burnt forest covered by ferns and shrubs (BF), three arable lands (A-1, A-2 and A-3) and a reclaimed grassland (GL) next to the arable lands. An acid-tolerant Janthinobacterium sp. strain A1-13 (Oxalobacteriaceae, beta -proteobacteria) isolated from A-1 soil was characterized as one of the most prominent N) sub(2)O-emitting bacteria in this region. Physiological characteristics of the N sub(2O emitter in the soilless culture system, including responses to soil environments, substrate concentration, C-source concentration, pH, and temperature, suggest that the N) sub(2)O emitting Janthinobacterium sp. strain A1-13 is highly adapted to reclaimed open peatland and primarily responsible for massive N sub(2O emissions from the acidic peat soils. Regulation of N) sub(2)O emitters in the reclaimed peatland for agricultural use is therefore one of the most important issues in preventing the greenhouse gas emission from acidic peat soil farmlands. View source