L-malic acid production by an albino strain of Monascus araneosus.

An albino mutant was isolated after treating Monascus araneosus AHU9087 with N-methyl-N'-nitro-N-nitrosoguanidine. All other physiological and biochemical characteristics were retained. The mutant did not produce any pigment but produced L-malic acid at 28 g/l, compared with 20 g/l by the parent strain, in media containing 10% (w/v) glucose after incubation under aerobic conditions for 5 days at 37°C.