Identification and Characterization of Bacteria Communities in Peat Soil of Paddy Farms in Lundu, Sarawak

Bacteria play a vital role in controlling biogeochemical cycles in the peat soil ecosystem. Most of the studies on soil bacteria focus mainly on the paddy farms in Indochina Peninsula including Laos, Vietnam, and Thailand while bacteria diversity is still poorly known in Malaysia, especially in Borneo Sarawak. The risk associated with the microbes in paddy farm is not well documented. This study was conducted to isolate and characterize the bacteria species from paddy fields located in various places in Lundu, Sarawak including Kampung Simboh Farm 1, Kampung Simboh Farm 2, Kampung Sukam, and Kampung Pueh. Four soil samples were collected randomly from each site. One gram of the soil sample was diluted in 9 mL of 0.80% (w/v) normal saline solution. The diluted sample was plated on Nutrient Agar plates and incubated at 28 °C for 24 h. A total of eleven bacteria isolates were then identified using 16S rRNA analysis. The physiological and biochemical of bacteria species were characterized by using Gram Staining and tested against eight antibiotics. The result showed that the most dominant bacterial taxa found with different abundances in all study sites were Firmicutes and followed by γ-proteobacteria. Gram-positive bacteria species were more prevalent in the peat soil ecosystem compared to Gram-negative bacteria. The antibiotic susceptibility testing showed that 100% of bacterial isolates are susceptible to Norfloxacin (NOR,10 μg). This study suggests that bacterial abundances and interaction between bacterial species promote and maintain a functional agroecosystem which improves crop productivity as well as plant nutrition and health. On another hand, the bacteria found in the farm may pose a health risk to those who are in direct contact with the soil in the farms, especially the farmers