The amino acid pool of Hansenula holstil: characterisation, and changes mediated by environment.

Amino acid pools extracted from Hansenula holstii grown in continuous culture with either ammonia or nitrate as sole source of nitrogen, under a variety of substrate limitations, were characterised and quantified. Pools from corresponding cultures were shown to be similar in size and composition, regardless of whether ammonia or nitrate was the nitrogen source. Large changes in pools (both quantitative and qualitative) occurred when cultures were grown under different substrate limitations. Such changes were particularly large in glutamate, glutamine, alanine, lysine and arginine; the possible significance of such environment-mediated changes is discussed.