Isolation and Characteristics of Acid- and Aluminum-tolerant Bacterium

Abstract

A screening was attempted to isolate microorganisms that tolerate high concentrations of H⁺ and ionic aluminum in acidic soils. A new microorganism that can grow in the presence of a high concentration of Al³⁺ at low pH was isolated from acidic tea fields. The microorganism, designated strain ST-3991, has been identified as a Flavobacterium sp. It can tolerate aluminum concentrations up to 2000ppm at pH 3.5. The bacterial growth was affected by the concentration of ionic aluminum. When the bacterium was incubated at an initial pH 3.3 in liquid medium containing 100 ppm aluminum, the pH of the medium increased steeply with time, and the medium reached pH 4.4 after 10 days. The bacterium is considered to be useful to improve acidified soils by decreasing the ionic aluminum concentration, while preserving indigenous terrestrial ecosystems.