“…Se\'eral yeasts are able to assimilate tiitrate as a nitrogen source, and the physiology and enzytnology of nitrate assimilation of some species, in genera such as Candida, Hansenula and Rhodotorula, is well understood (see reviews by Hipkin, 1989Hipkin, , 1990. Nitrite, an intermediate in the reductive assimilation of nitratc-nitrogen into ammonium-nitrogen, is also a potential source of nitrogen for these organisms and appears to play an important role in the regulation of nitrate assimilation (Gonzalez et al, 1994). However, although nitrite uptake has been studied in cyanobacteria and algae (Cresswell &: Syrett, 1982;Flores, Herrero & Guerrero.…”