Hydroxy-Al and cell-surface negativity are responsible for the enhanced sensitivity of Rhodotorula taiwanensis to aluminum by increased medium pH.

Aluminum (Al) is ubiquitous and toxic to microbes. High Al concentration and low pH are two key factors responsible for Al toxicity, but our present results contradict this idea. Here, an Al-tolerant yeast strain Rhodotorula taiwanensis RS1 was incubated in glucose media containing Al with a continuous pH gradient from pH 3.

A potential contribution of the less negatively charged cell wall to the high aluminum tolerance of Rhodotorula taiwanensis RS1.

Rhodotorula taiwanensis RS1 (Rt) is a high-aluminum (Al)-tolerant yeast that can survive Al at concentrations up to 200 mM. In this study, we compared Rt with an Al-sensitive congeneric strain, R. mucilaginosa AKU 4812 (Rm) and Al sensitive mutant 1 (alsm1) of Rt, to explore the Al tolerance mechanisms of Rt.